git/revision.c

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#include "cache.h"
#include "object-store.h"
#include "tag.h"
#include "blob.h"
#include "tree.h"
#include "commit.h"
#include "diff.h"
#include "diff-merges.h"
#include "refs.h"
#include "revision.h"
#include "repository.h"
#include "graph.h"
#include "grep.h"
#include "reflog-walk.h"
#include "patch-ids.h"
#include "decorate.h"
#include "log-tree.h"
#include "string-list.h"
Implement line-history search (git log -L) This is a rewrite of much of Bo's work, mainly in an effort to split it into smaller, easier to understand routines. The algorithm is built around the struct range_set, which encodes a series of line ranges as intervals [a,b). This is used in two contexts: * A set of lines we are tracking (which will change as we dig through history). * To encode diffs, as pairs of ranges. The main routine is range_set_map_across_diff(). It processes the diff between a commit C and some parent P. It determines which diff hunks are relevant to the ranges tracked in C, and computes the new ranges for P. The algorithm is then simply to process history in topological order from newest to oldest, computing ranges and (partial) diffs. At branch points, we need to merge the ranges we are watching. We will find that many commits do not affect the chosen ranges, and mark them TREESAME (in addition to those already filtered by pathspec limiting). Another pass of history simplification then gets rid of such commits. This is wired as an extra filtering pass in the log machinery. This currently only reduces code duplication, but should allow for other simplifications and options to be used. Finally, we hook a diff printer into the output chain. Ideally we would wire directly into the diff logic, to optionally use features like word diff. However, that will require some major reworking of the diff chain, so we completely replace the output with our own diff for now. As this was a GSoC project, and has quite some history by now, many people have helped. In no particular order, thanks go to Jakub Narebski <jnareb@gmail.com> Jens Lehmann <Jens.Lehmann@web.de> Jonathan Nieder <jrnieder@gmail.com> Junio C Hamano <gitster@pobox.com> Ramsay Jones <ramsay@ramsay1.demon.co.uk> Will Palmer <wmpalmer@gmail.com> Apologies to everyone I forgot. Signed-off-by: Bo Yang <struggleyb.nku@gmail.com> Signed-off-by: Thomas Rast <trast@student.ethz.ch> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-03-28 16:47:32 +00:00
#include "line-log.h"
#include "mailmap.h"
log: use true parents for diff even when rewriting When using pathspec filtering in combination with diff-based log output, parent simplification happens before the diff is computed. The diff is therefore against the *simplified* parents. This works okay, arguably by accident, in the normal case: simplification reduces to one parent as long as the commit is TREESAME to it. So the simplified parent of any given commit must have the same tree contents on the filtered paths as its true (unfiltered) parent. However, --full-diff breaks this guarantee, and indeed gives pretty spectacular results when comparing the output of git log --graph --stat ... git log --graph --full-diff --stat ... (--graph internally kicks in parent simplification, much like --parents). To fix it, store a copy of the parent list before simplification (in a slab) whenever --full-diff is in effect. Then use the stored parents instead of the simplified ones in the commit display code paths. The latter do not actually check for --full-diff to avoid duplicated code; they just grab the original parents if save_parents() has not been called for this revision walk. For ordinary commits it should be obvious that this is the right thing to do. Merge commits are a bit subtle. Observe that with default simplification, merge simplification is an all-or-nothing decision: either the merge is TREESAME to one parent and disappears, or it is different from all parents and the parent list remains intact. Redundant parents are not pruned, so the existing code also shows them as a merge. So if we do show a merge commit, the parent list just consists of the rewrite result on each parent. Running, e.g., --cc on this in --full-diff mode is not very useful: if any commits were skipped, some hunks will disagree with all sides of the merge (with one side, because commits were skipped; with the others, because they didn't have those changes in the first place). This triggers --cc showing these hunks spuriously. Therefore I believe that even for merge commits it is better to show the diffs wrt. the original parents. Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Helped-by: Junio C Hamano <gitster@pobox.com> Helped-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk> Signed-off-by: Thomas Rast <trast@inf.ethz.ch> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-31 20:13:20 +00:00
#include "commit-slab.h"
#include "dir.h"
#include "cache-tree.h"
#include "bisect.h"
#include "packfile.h"
#include "worktree.h"
#include "strvec.h"
#include "commit-reach.h"
revision.c: begin refactoring --topo-order logic When running 'git rev-list --topo-order' and its kin, the topo_order setting in struct rev_info implies the limited setting. This means that the following things happen during prepare_revision_walk(): * revs->limited implies we run limit_list() to walk the entire reachable set. There are some short-cuts here, such as if we perform a range query like 'git rev-list COMPARE..HEAD' and we can stop limit_list() when all queued commits are uninteresting. * revs->topo_order implies we run sort_in_topological_order(). See the implementation of that method in commit.c. It implies that the full set of commits to order is in the given commit_list. These two methods imply that a 'git rev-list --topo-order HEAD' command must walk the entire reachable set of commits _twice_ before returning a single result. If we have a commit-graph file with generation numbers computed, then there is a better way. This patch introduces some necessary logic redirection when we are in this situation. In v2.18.0, the commit-graph file contains zero-valued bytes in the positions where the generation number is stored in v2.19.0 and later. Thus, we use generation_numbers_enabled() to check if the commit-graph is available and has non-zero generation numbers. When setting revs->limited only because revs->topo_order is true, only do so if generation numbers are not available. There is no reason to use the new logic as it will behave similarly when all generation numbers are INFINITY or ZERO. In prepare_revision_walk(), if we have revs->topo_order but not revs->limited, then we trigger the new logic. It breaks the logic into three pieces, to fit with the existing framework: 1. init_topo_walk() fills a new struct topo_walk_info in the rev_info struct. We use the presence of this struct as a signal to use the new methods during our walk. In this patch, this method simply calls limit_list() and sort_in_topological_order(). In the future, this method will set up a new data structure to perform that logic in-line. 2. next_topo_commit() provides get_revision_1() with the next topo- ordered commit in the list. Currently, this simply pops the commit from revs->commits. 3. expand_topo_walk() provides get_revision_1() with a way to signal walking beyond the latest commit. Currently, this calls add_parents_to_list() exactly like the old logic. While this commit presents method redirection for performing the exact same logic as before, it allows the next commit to focus only on the new logic. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:20 +00:00
#include "commit-graph.h"
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
#include "prio-queue.h"
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
#include "hashmap.h"
#include "utf8.h"
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
#include "bloom.h"
#include "json-writer.h"
volatile show_early_output_fn_t show_early_output;
static const char *term_bad;
static const char *term_good;
implement_shared_commit_slab(revision_sources, char *);
line-log: more responsive, incremental 'git log -L' The current line-level log implementation performs a preprocessing step in prepare_revision_walk(), during which the line_log_filter() function filters and rewrites history to keep only commits modifying the given line range. This preprocessing affects both responsiveness and correctness: - Git doesn't produce any output during this preprocessing step. Checking whether a commit modified the given line range is somewhat expensive, so depending on the size of the given revision range this preprocessing can result in a significant delay before the first commit is shown. - Limiting the number of displayed commits (e.g. 'git log -3 -L...') doesn't limit the amount of work during preprocessing, because that limit is applied during history traversal. Alas, by that point this expensive preprocessing step has already churned through the whole revision range to find all commits modifying the revision range, even though only a few of them need to be shown. - It rewrites parents, with no way to turn it off. Without the user explicitly requesting parent rewriting any parent object ID shown should be that of the immediate parent, just like in case of a pathspec-limited history traversal without parent rewriting. However, after that preprocessing step rewrote history, the subsequent "regular" history traversal (i.e. get_revision() in a loop) only sees commits modifying the given line range. Consequently, it can only show the object ID of the last ancestor that modified the given line range (which might happen to be the immediate parent, but many-many times it isn't). This patch addresses both the correctness and, at least for the common case, the responsiveness issues by integrating line-level log filtering into the regular revision walking machinery: - Make process_ranges_arbitrary_commit(), the static function in 'line-log.c' deciding whether a commit modifies the given line range, public by removing the static keyword and adding the 'line_log_' prefix, so it can be called from other parts of the revision walking machinery. - If the user didn't explicitly ask for parent rewriting (which, I believe, is the most common case): - Call this now-public function during regular history traversal, namely from get_commit_action() to ignore any commits not modifying the given line range. Note that while this check is relatively expensive, it must be performed before other, much cheaper conditions, because the tracked line range must be adjusted even when the commit will end up being ignored by other conditions. - Skip the line_log_filter() call, i.e. the expensive preprocessing step, in prepare_revision_walk(), because, thanks to the above points, the revision walking machinery is now able to filter out commits not modifying the given line range while traversing history. This way the regular history traversal sees the unmodified history, and is therefore able to print the object ids of the immediate parents of the listed commits. The eliminated preprocessing step can greatly reduce the delay before the first commit is shown, see the numbers below. - However, if the user did explicitly ask for parent rewriting via '--parents' or a similar option, then stick with the current implementation for now, i.e. perform that expensive filtering and history rewriting in the preprocessing step just like we did before, leaving the initial delay as long as it was. I tried to integrate line-level log filtering with parent rewriting into the regular history traversal, but, unfortunately, several subtleties resisted... :) Maybe someday we'll figure out how to do that, but until then at least the simple and common (i.e. without parent rewriting) 'git log -L:func:file' commands can benefit from the reduced delay. This change makes the failing 'parent oids without parent rewriting' test in 't4211-line-log.sh' succeed. The reduced delay is most noticable when there's a commit modifying the line range near the tip of a large-ish revision range: # no parent rewriting requested, no commit-graph present $ time git --no-pager log -L:read_alternate_refs:sha1-file.c -1 v2.23.0 Before: real 0m9.570s user 0m9.494s sys 0m0.076s After: real 0m0.718s user 0m0.674s sys 0m0.044s A significant part of the remaining delay is spent reading and parsing commit objects in limit_list(). With the help of the commit-graph we can eliminate most of that reading and parsing overhead, so here are the timing results of the same command as above, but this time using the commit-graph: Before: real 0m8.874s user 0m8.816s sys 0m0.057s After: real 0m0.107s user 0m0.091s sys 0m0.013s The next patch will further reduce the remaining delay. To be clear: this patch doesn't actually optimize the line-level log, but merely moves most of the work from the preprocessing step to the history traversal, so the commits modifying the line range can be shown as soon as they are processed, and the traversal can be terminated as soon as the given number of commits are shown. Consequently, listing the full history of a line range, potentially all the way to the root commit, will take the same time as before (but at least the user might start reading the output earlier). Furthermore, if the most recent commit modifying the line range is far away from the starting revision, then that initial delay will still be significant. Additional testing by Derrick Stolee: In the Linux kernel repository, the MAINTAINERS file was changed ~3,500 times across the ~915,000 commits. In addition to that edit frequency, the file itself is quite large (~18,700 lines). This means that a significant portion of the computation is taken up by computing the patch-diff of the file. This patch improves the real time it takes to output the first result quite a bit: Command: git log -L 100,200:MAINTAINERS -n 1 >/dev/null Before: 3.88 s After: 0.71 s If we drop the "-n 1" in the command, then there is no change in end-to-end process time. This is because the command still needs to walk the entire commit history, which negates the point of this patch. This is expected. As a note for future reference, the ~4.3 seconds in the old code spends ~2.6 seconds computing the patch-diffs, and the rest of the time is spent walking commits and computing diffs for which paths changed at each commit. The changed-path Bloom filters could improve the end-to-end computation time (i.e. no "-n 1" in the command). Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-11 11:56:17 +00:00
static inline int want_ancestry(const struct rev_info *revs);
void show_object_with_name(FILE *out, struct object *obj, const char *name)
{
fprintf(out, "%s ", oid_to_hex(&obj->oid));
/*
* This "for (const char *p = ..." is made as a first step towards
* making use of such declarations elsewhere in our codebase. If
* it causes compilation problems on your platform, please report
* it to the Git mailing list at git@vger.kernel.org. In the meantime,
* adding -std=gnu99 to CFLAGS may help if you are with older GCC.
*/
for (const char *p = name; *p && *p != '\n'; p++)
fputc(*p, out);
fputc('\n', out);
}
static void mark_blob_uninteresting(struct blob *blob)
{
if (!blob)
return;
if (blob->object.flags & UNINTERESTING)
return;
blob->object.flags |= UNINTERESTING;
}
static void mark_tree_contents_uninteresting(struct repository *r,
struct tree *tree)
{
struct tree_desc desc;
tree_entry(): new tree-walking helper function This adds a "tree_entry()" function that combines the common operation of doing a "tree_entry_extract()" + "update_tree_entry()". It also has a simplified calling convention, designed for simple loops that traverse over a whole tree: the arguments are pointers to the tree descriptor and a name_entry structure to fill in, and it returns a boolean "true" if there was an entry left to be gotten in the tree. This allows tree traversal with struct tree_desc desc; struct name_entry entry; desc.buf = tree->buffer; desc.size = tree->size; while (tree_entry(&desc, &entry) { ... use "entry.{path, sha1, mode, pathlen}" ... } which is not only shorter than writing it out in full, it's hopefully less error prone too. [ It's actually a tad faster too - we don't need to recalculate the entry pathlength in both extract and update, but need to do it only once. Also, some callers can avoid doing a "strlen()" on the result, since it's returned as part of the name_entry structure. However, by now we're talking just 1% speedup on "git-rev-list --objects --all", and we're definitely at the point where tree walking is no longer the issue any more. ] NOTE! Not everybody wants to use this new helper function, since some of the tree walkers very much on purpose do the descriptor update separately from the entry extraction. So the "extract + update" sequence still remains as the core sequence, this is just a simplified interface. We should probably add a silly two-line inline helper function for initializing the descriptor from the "struct tree" too, just to cut down on the noise from that common "desc" initializer. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-05-30 16:45:45 +00:00
struct name_entry entry;
if (parse_tree_gently(tree, 1) < 0)
return;
init_tree_desc(&desc, tree->buffer, tree->size);
tree_entry(): new tree-walking helper function This adds a "tree_entry()" function that combines the common operation of doing a "tree_entry_extract()" + "update_tree_entry()". It also has a simplified calling convention, designed for simple loops that traverse over a whole tree: the arguments are pointers to the tree descriptor and a name_entry structure to fill in, and it returns a boolean "true" if there was an entry left to be gotten in the tree. This allows tree traversal with struct tree_desc desc; struct name_entry entry; desc.buf = tree->buffer; desc.size = tree->size; while (tree_entry(&desc, &entry) { ... use "entry.{path, sha1, mode, pathlen}" ... } which is not only shorter than writing it out in full, it's hopefully less error prone too. [ It's actually a tad faster too - we don't need to recalculate the entry pathlength in both extract and update, but need to do it only once. Also, some callers can avoid doing a "strlen()" on the result, since it's returned as part of the name_entry structure. However, by now we're talking just 1% speedup on "git-rev-list --objects --all", and we're definitely at the point where tree walking is no longer the issue any more. ] NOTE! Not everybody wants to use this new helper function, since some of the tree walkers very much on purpose do the descriptor update separately from the entry extraction. So the "extract + update" sequence still remains as the core sequence, this is just a simplified interface. We should probably add a silly two-line inline helper function for initializing the descriptor from the "struct tree" too, just to cut down on the noise from that common "desc" initializer. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-05-30 16:45:45 +00:00
while (tree_entry(&desc, &entry)) {
switch (object_type(entry.mode)) {
case OBJ_TREE:
mark_tree_uninteresting(r, lookup_tree(r, &entry.oid));
break;
case OBJ_BLOB:
mark_blob_uninteresting(lookup_blob(r, &entry.oid));
break;
default:
/* Subproject commit - not in this repository */
break;
}
}
/*
* We don't care about the tree any more
* after it has been marked uninteresting.
*/
free_tree_buffer(tree);
}
void mark_tree_uninteresting(struct repository *r, struct tree *tree)
revision: mark contents of an uninteresting tree uninteresting "git rev-list --objects ^A^{tree} B^{tree}" ought to mean "I want a list of objects inside B's tree, but please exclude the objects that appear inside A's tree". we see the top-level tree marked as uninteresting (i.e. ^A^{tree} in the above example) and call mark_tree_uninteresting() on it; this unfortunately prevents us from recursing into the tree and marking the objects in the tree as uninteresting. The reason why "git log ^A A" yields an empty set of commits, i.e. we do not have a similar issue for commits, is because we call mark_parents_uninteresting() after seeing an uninteresting commit. The uninteresting-ness of the commit itself does not prevent its parents from being marked as uninteresting. Introduce mark_tree_contents_uninteresting() and structure the code in handle_commit() in such a way that it makes it the responsibility of the callchain leading to this function to mark commits, trees and blobs as uninteresting, and also make it the responsibility of the helpers called from this function to mark objects that are reachable from them. Note that this is a very old bug that probably dates back to the day when "rev-list --objects" was introduced. The line to clear tree->object.parsed at the end of mark_tree_contents_uninteresting() can be removed when this fix is merged to the codebase after 6e454b9a (clear parsed flag when we free tree buffers, 2013-06-05). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-15 23:38:01 +00:00
{
struct object *obj;
revision: mark contents of an uninteresting tree uninteresting "git rev-list --objects ^A^{tree} B^{tree}" ought to mean "I want a list of objects inside B's tree, but please exclude the objects that appear inside A's tree". we see the top-level tree marked as uninteresting (i.e. ^A^{tree} in the above example) and call mark_tree_uninteresting() on it; this unfortunately prevents us from recursing into the tree and marking the objects in the tree as uninteresting. The reason why "git log ^A A" yields an empty set of commits, i.e. we do not have a similar issue for commits, is because we call mark_parents_uninteresting() after seeing an uninteresting commit. The uninteresting-ness of the commit itself does not prevent its parents from being marked as uninteresting. Introduce mark_tree_contents_uninteresting() and structure the code in handle_commit() in such a way that it makes it the responsibility of the callchain leading to this function to mark commits, trees and blobs as uninteresting, and also make it the responsibility of the helpers called from this function to mark objects that are reachable from them. Note that this is a very old bug that probably dates back to the day when "rev-list --objects" was introduced. The line to clear tree->object.parsed at the end of mark_tree_contents_uninteresting() can be removed when this fix is merged to the codebase after 6e454b9a (clear parsed flag when we free tree buffers, 2013-06-05). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-15 23:38:01 +00:00
if (!tree)
return;
obj = &tree->object;
revision: mark contents of an uninteresting tree uninteresting "git rev-list --objects ^A^{tree} B^{tree}" ought to mean "I want a list of objects inside B's tree, but please exclude the objects that appear inside A's tree". we see the top-level tree marked as uninteresting (i.e. ^A^{tree} in the above example) and call mark_tree_uninteresting() on it; this unfortunately prevents us from recursing into the tree and marking the objects in the tree as uninteresting. The reason why "git log ^A A" yields an empty set of commits, i.e. we do not have a similar issue for commits, is because we call mark_parents_uninteresting() after seeing an uninteresting commit. The uninteresting-ness of the commit itself does not prevent its parents from being marked as uninteresting. Introduce mark_tree_contents_uninteresting() and structure the code in handle_commit() in such a way that it makes it the responsibility of the callchain leading to this function to mark commits, trees and blobs as uninteresting, and also make it the responsibility of the helpers called from this function to mark objects that are reachable from them. Note that this is a very old bug that probably dates back to the day when "rev-list --objects" was introduced. The line to clear tree->object.parsed at the end of mark_tree_contents_uninteresting() can be removed when this fix is merged to the codebase after 6e454b9a (clear parsed flag when we free tree buffers, 2013-06-05). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-15 23:38:01 +00:00
if (obj->flags & UNINTERESTING)
return;
obj->flags |= UNINTERESTING;
mark_tree_contents_uninteresting(r, tree);
}
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
struct path_and_oids_entry {
struct hashmap_entry ent;
char *path;
struct oidset trees;
};
static int path_and_oids_cmp(const void *hashmap_cmp_fn_data,
const struct hashmap_entry *eptr,
const struct hashmap_entry *entry_or_key,
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
const void *keydata)
{
const struct path_and_oids_entry *e1, *e2;
e1 = container_of(eptr, const struct path_and_oids_entry, ent);
e2 = container_of(entry_or_key, const struct path_and_oids_entry, ent);
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
return strcmp(e1->path, e2->path);
}
static void paths_and_oids_clear(struct hashmap *map)
{
struct hashmap_iter iter;
struct path_and_oids_entry *entry;
hashmap_for_each_entry(map, &iter, entry, ent /* member name */) {
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
oidset_clear(&entry->trees);
free(entry->path);
}
hashmap_clear_and_free(map, struct path_and_oids_entry, ent);
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
}
static void paths_and_oids_insert(struct hashmap *map,
const char *path,
const struct object_id *oid)
{
int hash = strhash(path);
struct path_and_oids_entry key;
struct path_and_oids_entry *entry;
hashmap_entry_init(&key.ent, hash);
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
/* use a shallow copy for the lookup */
key.path = (char *)path;
oidset_init(&key.trees, 0);
entry = hashmap_get_entry(map, &key, ent, NULL);
if (!entry) {
CALLOC_ARRAY(entry, 1);
hashmap_entry_init(&entry->ent, hash);
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
entry->path = xstrdup(key.path);
oidset_init(&entry->trees, 16);
hashmap_put(map, &entry->ent);
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
}
oidset_insert(&entry->trees, oid);
}
static void add_children_by_path(struct repository *r,
struct tree *tree,
struct hashmap *map)
{
struct tree_desc desc;
struct name_entry entry;
if (!tree)
return;
if (parse_tree_gently(tree, 1) < 0)
return;
init_tree_desc(&desc, tree->buffer, tree->size);
while (tree_entry(&desc, &entry)) {
switch (object_type(entry.mode)) {
case OBJ_TREE:
paths_and_oids_insert(map, entry.path, &entry.oid);
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
if (tree->object.flags & UNINTERESTING) {
struct tree *child = lookup_tree(r, &entry.oid);
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
if (child)
child->object.flags |= UNINTERESTING;
}
break;
case OBJ_BLOB:
if (tree->object.flags & UNINTERESTING) {
struct blob *child = lookup_blob(r, &entry.oid);
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
if (child)
child->object.flags |= UNINTERESTING;
}
break;
default:
/* Subproject commit - not in this repository */
break;
}
}
free_tree_buffer(tree);
}
void mark_trees_uninteresting_sparse(struct repository *r,
struct oidset *trees)
{
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
unsigned has_interesting = 0, has_uninteresting = 0;
struct hashmap map = HASHMAP_INIT(path_and_oids_cmp, NULL);
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
struct hashmap_iter map_iter;
struct path_and_oids_entry *entry;
struct object_id *oid;
struct oidset_iter iter;
oidset_iter_init(trees, &iter);
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
while ((!has_interesting || !has_uninteresting) &&
(oid = oidset_iter_next(&iter))) {
struct tree *tree = lookup_tree(r, oid);
if (!tree)
continue;
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
if (tree->object.flags & UNINTERESTING)
has_uninteresting = 1;
else
has_interesting = 1;
}
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
/* Do not walk unless we have both types of trees. */
if (!has_uninteresting || !has_interesting)
return;
oidset_iter_init(trees, &iter);
while ((oid = oidset_iter_next(&iter))) {
struct tree *tree = lookup_tree(r, oid);
add_children_by_path(r, tree, &map);
}
hashmap_for_each_entry(&map, &map_iter, entry, ent /* member name */)
revision: implement sparse algorithm When enumerating objects to place in a pack-file during 'git pack-objects --revs', we discover the "frontier" of commits that we care about and the boundary with commit we find uninteresting. From that point, we walk trees to discover which trees and blobs are uninteresting. Finally, we walk trees from the interesting commits to find the interesting objects that are placed in the pack. This commit introduces a new, "sparse" way to discover the uninteresting trees. We use the perspective of a single user trying to push their topic to a large repository. That user likely changed a very small fraction of the paths in their working directory, but we spend a lot of time walking all reachable trees. The way to switch the logic to work in this sparse way is to start caring about which paths introduce new trees. While it is not possible to generate a diff between the frontier boundary and all of the interesting commits, we can simulate that behavior by inspecting all of the root trees as a whole, then recursing down to the set of trees at each path. We already had taken the first step by passing an oidset to mark_trees_uninteresting_sparse(). We now create a dictionary whose keys are paths and values are oidsets. We consider the set of trees that appear at each path. While we inspect a tree, we add its subtrees to the oidsets corresponding to the tree entry's path. We also mark trees as UNINTERESTING if the tree we are parsing is UNINTERESTING. To actually improve the performance, we need to terminate our recursion. If the oidset contains only UNINTERESTING trees, then we do not continue the recursion. This avoids walking trees that are likely to not be reachable from interesting trees. If the oidset contains only interesting trees, then we will walk these trees in the final stage that collects the intersting objects to place in the pack. Thus, we only recurse if the oidset contains both interesting and UNINITERESTING trees. There are a few ways that this is not a universally better option. First, we can pack extra objects. If someone copies a subtree from one tree to another, the first tree will appear UNINTERESTING and we will not recurse to see that the subtree should also be UNINTERESTING. We will walk the new tree and see the subtree as a "new" object and add it to the pack. A test is modified to demonstrate this behavior and to verify that the new logic is being exercised. Second, we can have extra memory pressure. If instead of being a single user pushing a small topic we are a server sending new objects from across the entire working directory, then we will gain very little (the recursion will rarely terminate early) but will spend extra time maintaining the path-oidset dictionaries. Despite these potential drawbacks, the benefits of the algorithm are clear. By adding a counter to 'add_children_by_path' and 'mark_tree_contents_uninteresting', I measured the number of parsed trees for the two algorithms in a variety of repos. For git.git, I used the following input: v2.19.0 ^v2.19.0~10 Objects to pack: 550 Walked (old alg): 282 Walked (new alg): 130 For the Linux repo, I used the following input: v4.18 ^v4.18~10 Objects to pack: 518 Walked (old alg): 4,836 Walked (new alg): 188 The two repos above are rather "wide and flat" compared to other repos that I have used in the past. As a comparison, I tested an old topic branch in the Azure DevOps repo, which has a much deeper folder structure than the Linux repo. Objects to pack: 220 Walked (old alg): 22,804 Walked (new alg): 129 I used the number of walked trees the main metric above because it is consistent across multiple runs. When I ran my tests, the performance of the pack-objects command with the same options could change the end-to-end time by 10x depending on the file system being warm. However, by repeating the same test on repeat I could get more consistent timing results. The git.git and Linux tests were too fast overall (less than 0.5s) to measure an end-to-end difference. The Azure DevOps case was slow enough to see the time improve from 15s to 1s in the warm case. The cold case was 90s to 9s in my testing. These improvements will have even larger benefits in the super- large Windows repository. In our experiments, we see the "Enumerate objects" phase of pack-objects taking 60-80% of the end-to-end time of non-trivial pushes, taking longer than the network time to send the pack and the server time to verify the pack. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-16 18:25:59 +00:00
mark_trees_uninteresting_sparse(r, &entry->trees);
paths_and_oids_clear(&map);
}
struct commit_stack {
struct commit **items;
size_t nr, alloc;
};
#define COMMIT_STACK_INIT { 0 }
static void commit_stack_push(struct commit_stack *stack, struct commit *commit)
{
ALLOC_GROW(stack->items, stack->nr + 1, stack->alloc);
stack->items[stack->nr++] = commit;
}
static struct commit *commit_stack_pop(struct commit_stack *stack)
{
return stack->nr ? stack->items[--stack->nr] : NULL;
}
static void commit_stack_clear(struct commit_stack *stack)
{
FREE_AND_NULL(stack->items);
stack->nr = stack->alloc = 0;
}
static void mark_one_parent_uninteresting(struct rev_info *revs, struct commit *commit,
struct commit_stack *pending)
{
struct commit_list *l;
if (commit->object.flags & UNINTERESTING)
return;
commit->object.flags |= UNINTERESTING;
/*
* Normally we haven't parsed the parent
* yet, so we won't have a parent of a parent
* here. However, it may turn out that we've
* reached this commit some other way (where it
* wasn't uninteresting), in which case we need
* to mark its parents recursively too..
*/
for (l = commit->parents; l; l = l->next) {
commit_stack_push(pending, l->item);
if (revs && revs->exclude_first_parent_only)
break;
}
}
void mark_parents_uninteresting(struct rev_info *revs, struct commit *commit)
{
struct commit_stack pending = COMMIT_STACK_INIT;
struct commit_list *l;
for (l = commit->parents; l; l = l->next) {
mark_one_parent_uninteresting(revs, l->item, &pending);
if (revs && revs->exclude_first_parent_only)
break;
}
while (pending.nr > 0)
mark_one_parent_uninteresting(revs, commit_stack_pop(&pending),
&pending);
commit_stack_clear(&pending);
}
traverse_commit_list: support pending blobs/trees with paths When we call traverse_commit_list, we may have trees and blobs in the pending array. As we process these, we pass the "name" field from the pending entry as the path of the object within the tree (which then becomes the root path if we recurse into subtrees). When we set up the traversal in prepare_revision_walk, though, the "name" field of any pending trees and blobs is likely to be the ref at which we found the object. We would not want to make this part of the path (e.g., doing so would make "git rev-list --objects v2.6.11-tree" in linux.git show paths like "v2.6.11-tree/Makefile", which is nonsensical). Therefore prepare_revision_walk sets the name field of each pending tree and blobs to the empty string. However, this leaves no room for a caller who does know the correct path of a pending object to propagate that information to the revision walker. We can fix this by making two related changes: 1. Use the "path" field as the path instead of the "name" field in traverse_commit_list. If the path is not set, default to "" (which is what we always ended up with in the current code, because of prepare_revision_walk). 2. In prepare_revision_walk, make a complete copy of the entry. This makes the path field available to the walker (if there is one), solving our problem. Leaving the name field intact is now OK, as we do not use it as a path due to point (1) above (and we can use it to make more meaningful error messages if we want). We also make the original "mode" field available to the walker, though it does not actually use it. Note that we still re-add the pending objects and free the old ones (so we may strdup the path and name only to free the old ones). This could be made more efficient by simply copying the object_array entries that we are keeping. However, that would require more restructuring of the code, and is not done here. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-15 22:43:19 +00:00
static void add_pending_object_with_path(struct rev_info *revs,
struct object *obj,
traverse_commit_list: support pending blobs/trees with paths When we call traverse_commit_list, we may have trees and blobs in the pending array. As we process these, we pass the "name" field from the pending entry as the path of the object within the tree (which then becomes the root path if we recurse into subtrees). When we set up the traversal in prepare_revision_walk, though, the "name" field of any pending trees and blobs is likely to be the ref at which we found the object. We would not want to make this part of the path (e.g., doing so would make "git rev-list --objects v2.6.11-tree" in linux.git show paths like "v2.6.11-tree/Makefile", which is nonsensical). Therefore prepare_revision_walk sets the name field of each pending tree and blobs to the empty string. However, this leaves no room for a caller who does know the correct path of a pending object to propagate that information to the revision walker. We can fix this by making two related changes: 1. Use the "path" field as the path instead of the "name" field in traverse_commit_list. If the path is not set, default to "" (which is what we always ended up with in the current code, because of prepare_revision_walk). 2. In prepare_revision_walk, make a complete copy of the entry. This makes the path field available to the walker (if there is one), solving our problem. Leaving the name field intact is now OK, as we do not use it as a path due to point (1) above (and we can use it to make more meaningful error messages if we want). We also make the original "mode" field available to the walker, though it does not actually use it. Note that we still re-add the pending objects and free the old ones (so we may strdup the path and name only to free the old ones). This could be made more efficient by simply copying the object_array entries that we are keeping. However, that would require more restructuring of the code, and is not done here. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-15 22:43:19 +00:00
const char *name, unsigned mode,
const char *path)
{
struct interpret_branch_name_options options = { 0 };
if (!obj)
return;
if (revs->no_walk && (obj->flags & UNINTERESTING))
revs->no_walk = 0;
if (revs->reflog_info && obj->type == OBJ_COMMIT) {
struct strbuf buf = STRBUF_INIT;
size_t namelen = strlen(name);
int len = interpret_branch_name(name, namelen, &buf, &options);
if (0 < len && len < namelen && buf.len)
strbuf_addstr(&buf, name + len);
reflog-walk: stop using fake parents The reflog-walk system works by putting a ref's tip into the pending queue, and then "traversing" the reflog by pretending that the parent of each commit is the previous reflog entry. This causes a number of user-visible oddities, as documented in t1414 (and the commit message which introduced it). We can fix all of them in one go by replacing the fake-reflog system with a much simpler one: just keeping a list of reflogs to show, and walking through them entry by entry. The implementation is fairly straight-forward, but there are a few items to note: 1. We obviously must skip calling add_parents_to_list() when we are traversing reflogs, since we do not want to walk the original parents at all. As a result, we must call try_to_simplify_commit() ourselves. There are other parts of add_parents_to_list() we skip, as well, but none of them should matter for a reflog traversal: - We do not allow UNINTERESTING commits, nor symmetric ranges (and we bail when these are used with "-g"). - Using --source makes no sense, since we aren't traversing. The reflog selector shows the same information with more detail. - Using --first-parent is still sensible, since you may want to see the first-parent diff for each entry. But since we're not traversing, we don't need to cull the parent list here. 2. Since we now just walk the reflog entries themselves, rather than starting with the ref tip, we now look at the "new" field of each entry rather than the "old" (i.e., we are showing entries, not faking parents). This removes all of the tricky logic around skipping past root commits. But note that we have no way to show an entry with the null sha1 in its "new" field (because such a commit obviously does not exist). Normally this would not happen, since we delete reflogs along with refs, but there is one special case. When we rename the currently checked out branch, we write two reflog entries into the HEAD log: one where the commit goes away, and another where it comes back. Prior to this commit, we show both entries with identical reflog messages. After this commit, we show only the "comes back" entry. See the update in t3200 which demonstrates this. Arguably either is fine, as the whole double-entry thing is a bit hacky in the first place. And until a recent fix, we truncated the traversal in such a case anyway, which was _definitely_ wrong. 3. We show individual reflogs in order, but choose which reflog to show at each stage based on which has the most recent timestamp. This interleaves the output from multiple reflogs based on date order, which is probably what you'd want with limiting like "-n 30". Note that the implementation aims for simplicity. It does a linear walk over the reflog queue for each commit it pulls, which may perform badly if you interleave an enormous number of reflogs. That seems like an unlikely use case; if we did want to handle it, we could probably keep a priority queue of reflogs, ordered by the timestamp of their current tip entry. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-07 09:14:07 +00:00
add_reflog_for_walk(revs->reflog_info,
(struct commit *)obj,
buf.buf[0] ? buf.buf: name);
strbuf_release(&buf);
reflog-walk: stop using fake parents The reflog-walk system works by putting a ref's tip into the pending queue, and then "traversing" the reflog by pretending that the parent of each commit is the previous reflog entry. This causes a number of user-visible oddities, as documented in t1414 (and the commit message which introduced it). We can fix all of them in one go by replacing the fake-reflog system with a much simpler one: just keeping a list of reflogs to show, and walking through them entry by entry. The implementation is fairly straight-forward, but there are a few items to note: 1. We obviously must skip calling add_parents_to_list() when we are traversing reflogs, since we do not want to walk the original parents at all. As a result, we must call try_to_simplify_commit() ourselves. There are other parts of add_parents_to_list() we skip, as well, but none of them should matter for a reflog traversal: - We do not allow UNINTERESTING commits, nor symmetric ranges (and we bail when these are used with "-g"). - Using --source makes no sense, since we aren't traversing. The reflog selector shows the same information with more detail. - Using --first-parent is still sensible, since you may want to see the first-parent diff for each entry. But since we're not traversing, we don't need to cull the parent list here. 2. Since we now just walk the reflog entries themselves, rather than starting with the ref tip, we now look at the "new" field of each entry rather than the "old" (i.e., we are showing entries, not faking parents). This removes all of the tricky logic around skipping past root commits. But note that we have no way to show an entry with the null sha1 in its "new" field (because such a commit obviously does not exist). Normally this would not happen, since we delete reflogs along with refs, but there is one special case. When we rename the currently checked out branch, we write two reflog entries into the HEAD log: one where the commit goes away, and another where it comes back. Prior to this commit, we show both entries with identical reflog messages. After this commit, we show only the "comes back" entry. See the update in t3200 which demonstrates this. Arguably either is fine, as the whole double-entry thing is a bit hacky in the first place. And until a recent fix, we truncated the traversal in such a case anyway, which was _definitely_ wrong. 3. We show individual reflogs in order, but choose which reflog to show at each stage based on which has the most recent timestamp. This interleaves the output from multiple reflogs based on date order, which is probably what you'd want with limiting like "-n 30". Note that the implementation aims for simplicity. It does a linear walk over the reflog queue for each commit it pulls, which may perform badly if you interleave an enormous number of reflogs. That seems like an unlikely use case; if we did want to handle it, we could probably keep a priority queue of reflogs, ordered by the timestamp of their current tip entry. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-07 09:14:07 +00:00
return; /* do not add the commit itself */
}
traverse_commit_list: support pending blobs/trees with paths When we call traverse_commit_list, we may have trees and blobs in the pending array. As we process these, we pass the "name" field from the pending entry as the path of the object within the tree (which then becomes the root path if we recurse into subtrees). When we set up the traversal in prepare_revision_walk, though, the "name" field of any pending trees and blobs is likely to be the ref at which we found the object. We would not want to make this part of the path (e.g., doing so would make "git rev-list --objects v2.6.11-tree" in linux.git show paths like "v2.6.11-tree/Makefile", which is nonsensical). Therefore prepare_revision_walk sets the name field of each pending tree and blobs to the empty string. However, this leaves no room for a caller who does know the correct path of a pending object to propagate that information to the revision walker. We can fix this by making two related changes: 1. Use the "path" field as the path instead of the "name" field in traverse_commit_list. If the path is not set, default to "" (which is what we always ended up with in the current code, because of prepare_revision_walk). 2. In prepare_revision_walk, make a complete copy of the entry. This makes the path field available to the walker (if there is one), solving our problem. Leaving the name field intact is now OK, as we do not use it as a path due to point (1) above (and we can use it to make more meaningful error messages if we want). We also make the original "mode" field available to the walker, though it does not actually use it. Note that we still re-add the pending objects and free the old ones (so we may strdup the path and name only to free the old ones). This could be made more efficient by simply copying the object_array entries that we are keeping. However, that would require more restructuring of the code, and is not done here. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-15 22:43:19 +00:00
add_object_array_with_path(obj, name, &revs->pending, mode, path);
}
static void add_pending_object_with_mode(struct rev_info *revs,
struct object *obj,
const char *name, unsigned mode)
{
add_pending_object_with_path(revs, obj, name, mode, NULL);
}
void add_pending_object(struct rev_info *revs,
struct object *obj, const char *name)
{
add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
}
void add_head_to_pending(struct rev_info *revs)
{
struct object_id oid;
struct object *obj;
if (get_oid("HEAD", &oid))
return;
obj = parse_object(revs->repo, &oid);
if (!obj)
return;
add_pending_object(revs, obj, "HEAD");
}
static struct object *get_reference(struct rev_info *revs, const char *name,
const struct object_id *oid,
unsigned int flags)
{
struct object *object;
revision: avoid hitting packfiles when commits are in commit-graph When queueing references in git-rev-list(1), we try to optimize parsing of commits via the commit-graph. To do so, we first look up the object's type, and if it is a commit we call `repo_parse_commit()` instead of `parse_object()`. This is quite inefficient though given that we're always uncompressing the object header in order to determine the type. Instead, we can opportunistically search the commit-graph for the object ID: in case it's found, we know it's a commit and can directly fill in the commit object without having to uncompress the object header. Expose a new function `lookup_commit_in_graph()`, which tries to find a commit in the commit-graph by ID, and convert `get_reference()` to use this function. This provides a big performance win in cases where we load references in a repository with lots of references pointing to commits. The following has been executed in a real-world repository with about 2.2 million refs: Benchmark #1: HEAD~: rev-list --unsorted-input --objects --quiet --not --all --not $newrev Time (mean ± σ): 4.458 s ± 0.044 s [User: 4.115 s, System: 0.342 s] Range (min … max): 4.409 s … 4.534 s 10 runs Benchmark #2: HEAD: rev-list --unsorted-input --objects --quiet --not --all --not $newrev Time (mean ± σ): 3.089 s ± 0.015 s [User: 2.768 s, System: 0.321 s] Range (min … max): 3.061 s … 3.105 s 10 runs Summary 'HEAD: rev-list --unsorted-input --objects --quiet --not --all --not $newrev' ran 1.44 ± 0.02 times faster than 'HEAD~: rev-list --unsorted-input --objects --quiet --not --all --not $newrev' Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-09 08:12:03 +00:00
struct commit *commit;
/*
revision: avoid hitting packfiles when commits are in commit-graph When queueing references in git-rev-list(1), we try to optimize parsing of commits via the commit-graph. To do so, we first look up the object's type, and if it is a commit we call `repo_parse_commit()` instead of `parse_object()`. This is quite inefficient though given that we're always uncompressing the object header in order to determine the type. Instead, we can opportunistically search the commit-graph for the object ID: in case it's found, we know it's a commit and can directly fill in the commit object without having to uncompress the object header. Expose a new function `lookup_commit_in_graph()`, which tries to find a commit in the commit-graph by ID, and convert `get_reference()` to use this function. This provides a big performance win in cases where we load references in a repository with lots of references pointing to commits. The following has been executed in a real-world repository with about 2.2 million refs: Benchmark #1: HEAD~: rev-list --unsorted-input --objects --quiet --not --all --not $newrev Time (mean ± σ): 4.458 s ± 0.044 s [User: 4.115 s, System: 0.342 s] Range (min … max): 4.409 s … 4.534 s 10 runs Benchmark #2: HEAD: rev-list --unsorted-input --objects --quiet --not --all --not $newrev Time (mean ± σ): 3.089 s ± 0.015 s [User: 2.768 s, System: 0.321 s] Range (min … max): 3.061 s … 3.105 s 10 runs Summary 'HEAD: rev-list --unsorted-input --objects --quiet --not --all --not $newrev' ran 1.44 ± 0.02 times faster than 'HEAD~: rev-list --unsorted-input --objects --quiet --not --all --not $newrev' Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-09 08:12:03 +00:00
* If the repository has commit graphs, we try to opportunistically
* look up the object ID in those graphs. Like this, we can avoid
* parsing commit data from disk.
*/
revision: avoid hitting packfiles when commits are in commit-graph When queueing references in git-rev-list(1), we try to optimize parsing of commits via the commit-graph. To do so, we first look up the object's type, and if it is a commit we call `repo_parse_commit()` instead of `parse_object()`. This is quite inefficient though given that we're always uncompressing the object header in order to determine the type. Instead, we can opportunistically search the commit-graph for the object ID: in case it's found, we know it's a commit and can directly fill in the commit object without having to uncompress the object header. Expose a new function `lookup_commit_in_graph()`, which tries to find a commit in the commit-graph by ID, and convert `get_reference()` to use this function. This provides a big performance win in cases where we load references in a repository with lots of references pointing to commits. The following has been executed in a real-world repository with about 2.2 million refs: Benchmark #1: HEAD~: rev-list --unsorted-input --objects --quiet --not --all --not $newrev Time (mean ± σ): 4.458 s ± 0.044 s [User: 4.115 s, System: 0.342 s] Range (min … max): 4.409 s … 4.534 s 10 runs Benchmark #2: HEAD: rev-list --unsorted-input --objects --quiet --not --all --not $newrev Time (mean ± σ): 3.089 s ± 0.015 s [User: 2.768 s, System: 0.321 s] Range (min … max): 3.061 s … 3.105 s 10 runs Summary 'HEAD: rev-list --unsorted-input --objects --quiet --not --all --not $newrev' ran 1.44 ± 0.02 times faster than 'HEAD~: rev-list --unsorted-input --objects --quiet --not --all --not $newrev' Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-09 08:12:03 +00:00
commit = lookup_commit_in_graph(revs->repo, oid);
if (commit)
object = &commit->object;
else
object = parse_object(revs->repo, oid);
if (!object) {
if (revs->ignore_missing)
return object;
if (revs->exclude_promisor_objects && is_promisor_object(oid))
return NULL;
die("bad object %s", name);
}
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
object->flags |= flags;
return object;
}
void add_pending_oid(struct rev_info *revs, const char *name,
const struct object_id *oid, unsigned int flags)
{
struct object *object = get_reference(revs, name, oid, flags);
add_pending_object(revs, object, name);
}
static struct commit *handle_commit(struct rev_info *revs,
traverse_commit_list: support pending blobs/trees with paths When we call traverse_commit_list, we may have trees and blobs in the pending array. As we process these, we pass the "name" field from the pending entry as the path of the object within the tree (which then becomes the root path if we recurse into subtrees). When we set up the traversal in prepare_revision_walk, though, the "name" field of any pending trees and blobs is likely to be the ref at which we found the object. We would not want to make this part of the path (e.g., doing so would make "git rev-list --objects v2.6.11-tree" in linux.git show paths like "v2.6.11-tree/Makefile", which is nonsensical). Therefore prepare_revision_walk sets the name field of each pending tree and blobs to the empty string. However, this leaves no room for a caller who does know the correct path of a pending object to propagate that information to the revision walker. We can fix this by making two related changes: 1. Use the "path" field as the path instead of the "name" field in traverse_commit_list. If the path is not set, default to "" (which is what we always ended up with in the current code, because of prepare_revision_walk). 2. In prepare_revision_walk, make a complete copy of the entry. This makes the path field available to the walker (if there is one), solving our problem. Leaving the name field intact is now OK, as we do not use it as a path due to point (1) above (and we can use it to make more meaningful error messages if we want). We also make the original "mode" field available to the walker, though it does not actually use it. Note that we still re-add the pending objects and free the old ones (so we may strdup the path and name only to free the old ones). This could be made more efficient by simply copying the object_array entries that we are keeping. However, that would require more restructuring of the code, and is not done here. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-15 22:43:19 +00:00
struct object_array_entry *entry)
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
{
traverse_commit_list: support pending blobs/trees with paths When we call traverse_commit_list, we may have trees and blobs in the pending array. As we process these, we pass the "name" field from the pending entry as the path of the object within the tree (which then becomes the root path if we recurse into subtrees). When we set up the traversal in prepare_revision_walk, though, the "name" field of any pending trees and blobs is likely to be the ref at which we found the object. We would not want to make this part of the path (e.g., doing so would make "git rev-list --objects v2.6.11-tree" in linux.git show paths like "v2.6.11-tree/Makefile", which is nonsensical). Therefore prepare_revision_walk sets the name field of each pending tree and blobs to the empty string. However, this leaves no room for a caller who does know the correct path of a pending object to propagate that information to the revision walker. We can fix this by making two related changes: 1. Use the "path" field as the path instead of the "name" field in traverse_commit_list. If the path is not set, default to "" (which is what we always ended up with in the current code, because of prepare_revision_walk). 2. In prepare_revision_walk, make a complete copy of the entry. This makes the path field available to the walker (if there is one), solving our problem. Leaving the name field intact is now OK, as we do not use it as a path due to point (1) above (and we can use it to make more meaningful error messages if we want). We also make the original "mode" field available to the walker, though it does not actually use it. Note that we still re-add the pending objects and free the old ones (so we may strdup the path and name only to free the old ones). This could be made more efficient by simply copying the object_array entries that we are keeping. However, that would require more restructuring of the code, and is not done here. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-15 22:43:19 +00:00
struct object *object = entry->item;
const char *name = entry->name;
const char *path = entry->path;
unsigned int mode = entry->mode;
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
unsigned long flags = object->flags;
/*
* Tag object? Look what it points to..
*/
while (object->type == OBJ_TAG) {
struct tag *tag = (struct tag *) object;
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
if (revs->tag_objects && !(flags & UNINTERESTING))
add_pending_object(revs, object, tag->tag);
object = parse_object(revs->repo, get_tagged_oid(tag));
if (!object) {
if (revs->ignore_missing_links || (flags & UNINTERESTING))
return NULL;
if (revs->exclude_promisor_objects &&
is_promisor_object(&tag->tagged->oid))
return NULL;
die("bad object %s", oid_to_hex(&tag->tagged->oid));
}
object->flags |= flags;
traverse_commit_list: support pending blobs/trees with paths When we call traverse_commit_list, we may have trees and blobs in the pending array. As we process these, we pass the "name" field from the pending entry as the path of the object within the tree (which then becomes the root path if we recurse into subtrees). When we set up the traversal in prepare_revision_walk, though, the "name" field of any pending trees and blobs is likely to be the ref at which we found the object. We would not want to make this part of the path (e.g., doing so would make "git rev-list --objects v2.6.11-tree" in linux.git show paths like "v2.6.11-tree/Makefile", which is nonsensical). Therefore prepare_revision_walk sets the name field of each pending tree and blobs to the empty string. However, this leaves no room for a caller who does know the correct path of a pending object to propagate that information to the revision walker. We can fix this by making two related changes: 1. Use the "path" field as the path instead of the "name" field in traverse_commit_list. If the path is not set, default to "" (which is what we always ended up with in the current code, because of prepare_revision_walk). 2. In prepare_revision_walk, make a complete copy of the entry. This makes the path field available to the walker (if there is one), solving our problem. Leaving the name field intact is now OK, as we do not use it as a path due to point (1) above (and we can use it to make more meaningful error messages if we want). We also make the original "mode" field available to the walker, though it does not actually use it. Note that we still re-add the pending objects and free the old ones (so we may strdup the path and name only to free the old ones). This could be made more efficient by simply copying the object_array entries that we are keeping. However, that would require more restructuring of the code, and is not done here. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-15 22:43:19 +00:00
/*
* We'll handle the tagged object by looping or dropping
* through to the non-tag handlers below. Do not
* propagate path data from the tag's pending entry.
traverse_commit_list: support pending blobs/trees with paths When we call traverse_commit_list, we may have trees and blobs in the pending array. As we process these, we pass the "name" field from the pending entry as the path of the object within the tree (which then becomes the root path if we recurse into subtrees). When we set up the traversal in prepare_revision_walk, though, the "name" field of any pending trees and blobs is likely to be the ref at which we found the object. We would not want to make this part of the path (e.g., doing so would make "git rev-list --objects v2.6.11-tree" in linux.git show paths like "v2.6.11-tree/Makefile", which is nonsensical). Therefore prepare_revision_walk sets the name field of each pending tree and blobs to the empty string. However, this leaves no room for a caller who does know the correct path of a pending object to propagate that information to the revision walker. We can fix this by making two related changes: 1. Use the "path" field as the path instead of the "name" field in traverse_commit_list. If the path is not set, default to "" (which is what we always ended up with in the current code, because of prepare_revision_walk). 2. In prepare_revision_walk, make a complete copy of the entry. This makes the path field available to the walker (if there is one), solving our problem. Leaving the name field intact is now OK, as we do not use it as a path due to point (1) above (and we can use it to make more meaningful error messages if we want). We also make the original "mode" field available to the walker, though it does not actually use it. Note that we still re-add the pending objects and free the old ones (so we may strdup the path and name only to free the old ones). This could be made more efficient by simply copying the object_array entries that we are keeping. However, that would require more restructuring of the code, and is not done here. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-15 22:43:19 +00:00
*/
path = NULL;
mode = 0;
}
/*
* Commit object? Just return it, we'll do all the complex
* reachability crud.
*/
if (object->type == OBJ_COMMIT) {
struct commit *commit = (struct commit *)object;
if (repo_parse_commit(revs->repo, commit) < 0)
die("unable to parse commit %s", name);
if (flags & UNINTERESTING) {
mark_parents_uninteresting(revs, commit);
revision: use generation for A..B --topo-order queries If a commit-graph exists with computed generation numbers, then a 'git rev-list --topo-order -n <N> <rev>' query will use those generation numbers to reduce the number of commits walked before writing N commits. One caveat put in b454241 (revision.c: generation-based topo-order algorithm, 2018-11-01) was to not enable the new algorithm for queries with a revision range "A..B". The logic was placed to walk from "A" and mark those commits as uninteresting, but the performance was actually worse than the existing logic in some cases. The root cause of this performance degradation is that generation numbers _increase_ the number of commits we walk relative to the existing heuristic of walking by commit date. While generation numbers actually guarantee that the algorithm is correct, the existing logic is very rarely wrong and that added requirement is not worth the cost. This motivates the planned "corrected commit date" to replace generation numbers in a future version of Git. The current change enables the logic to use whatever reachability index is currently in the commit-graph (generation numbers or corrected commit date). The limited flag in struct rev_info forces a full walk of the commit history (after discovering the A..B range). Previosuly, it is enabled whenever we see an uninteresting commit. We prevent enabling the parameter when we are planning to use the reachability index for a topo-order. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-05-21 13:14:38 +00:00
if (!revs->topo_order || !generation_numbers_enabled(the_repository))
revs->limited = 1;
}
if (revs->sources) {
char **slot = revision_sources_at(revs->sources, commit);
if (!*slot)
*slot = xstrdup(name);
}
return commit;
}
/*
* Tree object? Either mark it uninteresting, or add it
* to the list of objects to look at later..
*/
if (object->type == OBJ_TREE) {
struct tree *tree = (struct tree *)object;
if (!revs->tree_objects)
return NULL;
if (flags & UNINTERESTING) {
mark_tree_contents_uninteresting(revs->repo, tree);
return NULL;
}
traverse_commit_list: support pending blobs/trees with paths When we call traverse_commit_list, we may have trees and blobs in the pending array. As we process these, we pass the "name" field from the pending entry as the path of the object within the tree (which then becomes the root path if we recurse into subtrees). When we set up the traversal in prepare_revision_walk, though, the "name" field of any pending trees and blobs is likely to be the ref at which we found the object. We would not want to make this part of the path (e.g., doing so would make "git rev-list --objects v2.6.11-tree" in linux.git show paths like "v2.6.11-tree/Makefile", which is nonsensical). Therefore prepare_revision_walk sets the name field of each pending tree and blobs to the empty string. However, this leaves no room for a caller who does know the correct path of a pending object to propagate that information to the revision walker. We can fix this by making two related changes: 1. Use the "path" field as the path instead of the "name" field in traverse_commit_list. If the path is not set, default to "" (which is what we always ended up with in the current code, because of prepare_revision_walk). 2. In prepare_revision_walk, make a complete copy of the entry. This makes the path field available to the walker (if there is one), solving our problem. Leaving the name field intact is now OK, as we do not use it as a path due to point (1) above (and we can use it to make more meaningful error messages if we want). We also make the original "mode" field available to the walker, though it does not actually use it. Note that we still re-add the pending objects and free the old ones (so we may strdup the path and name only to free the old ones). This could be made more efficient by simply copying the object_array entries that we are keeping. However, that would require more restructuring of the code, and is not done here. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-15 22:43:19 +00:00
add_pending_object_with_path(revs, object, name, mode, path);
return NULL;
}
/*
* Blob object? You know the drill by now..
*/
if (object->type == OBJ_BLOB) {
if (!revs->blob_objects)
return NULL;
if (flags & UNINTERESTING)
return NULL;
traverse_commit_list: support pending blobs/trees with paths When we call traverse_commit_list, we may have trees and blobs in the pending array. As we process these, we pass the "name" field from the pending entry as the path of the object within the tree (which then becomes the root path if we recurse into subtrees). When we set up the traversal in prepare_revision_walk, though, the "name" field of any pending trees and blobs is likely to be the ref at which we found the object. We would not want to make this part of the path (e.g., doing so would make "git rev-list --objects v2.6.11-tree" in linux.git show paths like "v2.6.11-tree/Makefile", which is nonsensical). Therefore prepare_revision_walk sets the name field of each pending tree and blobs to the empty string. However, this leaves no room for a caller who does know the correct path of a pending object to propagate that information to the revision walker. We can fix this by making two related changes: 1. Use the "path" field as the path instead of the "name" field in traverse_commit_list. If the path is not set, default to "" (which is what we always ended up with in the current code, because of prepare_revision_walk). 2. In prepare_revision_walk, make a complete copy of the entry. This makes the path field available to the walker (if there is one), solving our problem. Leaving the name field intact is now OK, as we do not use it as a path due to point (1) above (and we can use it to make more meaningful error messages if we want). We also make the original "mode" field available to the walker, though it does not actually use it. Note that we still re-add the pending objects and free the old ones (so we may strdup the path and name only to free the old ones). This could be made more efficient by simply copying the object_array entries that we are keeping. However, that would require more restructuring of the code, and is not done here. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-15 22:43:19 +00:00
add_pending_object_with_path(revs, object, name, mode, path);
return NULL;
}
die("%s is unknown object", name);
}
limit_list: avoid quadratic behavior from still_interesting When we are limiting a rev-list traversal due to UNINTERESTING refs, we have to walk down the tips (both interesting and uninteresting) to find where they intersect. We keep a queue of commits to examine, pop commits off the queue one by one, and potentially add their parents. The size of the queue will naturally fluctuate based on the "width" of the history graph; i.e., the number of simultaneous lines of development. But for the most part it will stay in the same ballpark as the initial number of tips we fed, shrinking over time (as we hit common ancestors of the tips). So roughly speaking, if we start with `N` tips, we'll spend much of the time with a queue around `N` items. For each UNINTERESTING commit we pop, we call still_interesting to check whether marking its parents as UNINTERESTING has made the whole queue uninteresting (in which case we can quit early). Because the queue is stored as a linked list, this is `O(N)`, where `N` is the number of items in the queue. So processing a queue with `N` commits marked UNINTERESTING (and one or more interesting commits) will take `O(N^2)`. If you feed a lot of positive tips, this isn't a problem. They aren't UNINTERESTING, so they don't incur the still_interesting check. It also isn't a problem if you traverse from an interesting tip to some UNINTERESTING bases. We order the queue by recency, so the interesting commits stay at the front of the queue as we walk down them. The linear check can exit early as soon as it sees one interesting commit left in the queue. But if you want to know whether an older commit is reachable from a set of newer tips, we end up processing in the opposite direction: from the UNINTERESTING ones down to the interesting one. This may happen when we call: git rev-list $commits --not --all in check_everything_connected after a fetch. If we fetched something much older than most of our refs, and if we have a large number of refs, the traversal cost is dominated by the quadratic behavior. These commands simulate the connectivity check of such a fetch, when you have `$n` distinct refs in the receiver: # positive ref is 100,000 commits deep git rev-list --all | head -100000 | tail -1 >input # huge number of more recent negative refs git rev-list --all | head -$n | sed s/^/^/ >>input time git rev-list --stdin <input Here are timings for various `n` on the linux.git repository. The `n=1` case provides a baseline for just walking the commits, which lets us see the still_interesting overhead. The times marked with `+` subtract that baseline to show just the extra time growth due to the large number of refs. The `x` numbers show the slowdown of the adjusted time versus the prior trial. n | before | after -------------------------------------------------------- 1 | 0.991s | 0.848s 10000 | 1.120s (+0.129s) | 0.885s (+0.037s) 20000 | 1.451s (+0.460s, 3.5x) | 0.923s (+0.075s, 2.0x) 40000 | 2.731s (+1.740s, 3.8x) | 0.994s (+0.146s, 1.9x) 80000 | 8.235s (+7.244s, 4.2x) | 1.123s (+0.275s, 1.9x) Each trial doubles `n`, so you can see the quadratic (`4x`) behavior before this patch. Afterwards, we have a roughly linear relationship. The implementation is fairly straightforward. Whenever we do the linear search, we cache the interesting commit we find, and next time check it before doing another linear search. If that commit is removed from the list or becomes UNINTERESTING itself, then we fall back to the linear search. This is very similar to the trick used by fce87ae (Fix quadratic performance in rewrite_one., 2008-07-12). I considered and rejected several possible alternatives: 1. Keep a count of UNINTERESTING commits in the queue. This requires managing the count not only when removing an item from the queue, but also when marking an item as UNINTERESTING. That requires touching the other functions which mark commits, and would require knowing quickly which commits are in the queue (lookup in the queue is linear, so we would need an auxiliary structure or to also maintain an IN_QUEUE flag in each commit object). 2. Keep a separate list of interesting commits. Drop items from it when they are dropped from the queue, or if they become UNINTERESTING. This again suffers from extra complexity to maintain the list, not to mention CPU and memory. 3. Use a better data structure for the queue. This is something that could help the fix in fce87ae, because we order the queue by recency, and it is about inserting quickly in recency order. So a normal priority queue would help there. But here, we cannot disturb the order of the queue, which makes things harder. We really do need an auxiliary index to track the flag we care about, which is basically option (2) above. The "cache" trick is simple, and the numbers above show that it works well in practice. This is because the length of time it takes to find an interesting commit is proportional to the length of time it will remain cached (i.e., if we have to walk a long way to find it, it also means we have to pop a lot of elements in the queue until we get rid of it and have to find another interesting commit). The worst case is still quadratic, though. We could have `N` uninteresting commits at the front of the queue, followed by `N` interesting commits, where commit `i` has parent `i+N`. When we pop commit `i`, we will notice that the parent of the next commit, `i+1+N` is still interesting and cache it. But then handling commit `i+1`, we will mark its parent `i+1+N` uninteresting, and immediately invalidate our cache. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-17 22:11:04 +00:00
static int everybody_uninteresting(struct commit_list *orig,
struct commit **interesting_cache)
{
struct commit_list *list = orig;
limit_list: avoid quadratic behavior from still_interesting When we are limiting a rev-list traversal due to UNINTERESTING refs, we have to walk down the tips (both interesting and uninteresting) to find where they intersect. We keep a queue of commits to examine, pop commits off the queue one by one, and potentially add their parents. The size of the queue will naturally fluctuate based on the "width" of the history graph; i.e., the number of simultaneous lines of development. But for the most part it will stay in the same ballpark as the initial number of tips we fed, shrinking over time (as we hit common ancestors of the tips). So roughly speaking, if we start with `N` tips, we'll spend much of the time with a queue around `N` items. For each UNINTERESTING commit we pop, we call still_interesting to check whether marking its parents as UNINTERESTING has made the whole queue uninteresting (in which case we can quit early). Because the queue is stored as a linked list, this is `O(N)`, where `N` is the number of items in the queue. So processing a queue with `N` commits marked UNINTERESTING (and one or more interesting commits) will take `O(N^2)`. If you feed a lot of positive tips, this isn't a problem. They aren't UNINTERESTING, so they don't incur the still_interesting check. It also isn't a problem if you traverse from an interesting tip to some UNINTERESTING bases. We order the queue by recency, so the interesting commits stay at the front of the queue as we walk down them. The linear check can exit early as soon as it sees one interesting commit left in the queue. But if you want to know whether an older commit is reachable from a set of newer tips, we end up processing in the opposite direction: from the UNINTERESTING ones down to the interesting one. This may happen when we call: git rev-list $commits --not --all in check_everything_connected after a fetch. If we fetched something much older than most of our refs, and if we have a large number of refs, the traversal cost is dominated by the quadratic behavior. These commands simulate the connectivity check of such a fetch, when you have `$n` distinct refs in the receiver: # positive ref is 100,000 commits deep git rev-list --all | head -100000 | tail -1 >input # huge number of more recent negative refs git rev-list --all | head -$n | sed s/^/^/ >>input time git rev-list --stdin <input Here are timings for various `n` on the linux.git repository. The `n=1` case provides a baseline for just walking the commits, which lets us see the still_interesting overhead. The times marked with `+` subtract that baseline to show just the extra time growth due to the large number of refs. The `x` numbers show the slowdown of the adjusted time versus the prior trial. n | before | after -------------------------------------------------------- 1 | 0.991s | 0.848s 10000 | 1.120s (+0.129s) | 0.885s (+0.037s) 20000 | 1.451s (+0.460s, 3.5x) | 0.923s (+0.075s, 2.0x) 40000 | 2.731s (+1.740s, 3.8x) | 0.994s (+0.146s, 1.9x) 80000 | 8.235s (+7.244s, 4.2x) | 1.123s (+0.275s, 1.9x) Each trial doubles `n`, so you can see the quadratic (`4x`) behavior before this patch. Afterwards, we have a roughly linear relationship. The implementation is fairly straightforward. Whenever we do the linear search, we cache the interesting commit we find, and next time check it before doing another linear search. If that commit is removed from the list or becomes UNINTERESTING itself, then we fall back to the linear search. This is very similar to the trick used by fce87ae (Fix quadratic performance in rewrite_one., 2008-07-12). I considered and rejected several possible alternatives: 1. Keep a count of UNINTERESTING commits in the queue. This requires managing the count not only when removing an item from the queue, but also when marking an item as UNINTERESTING. That requires touching the other functions which mark commits, and would require knowing quickly which commits are in the queue (lookup in the queue is linear, so we would need an auxiliary structure or to also maintain an IN_QUEUE flag in each commit object). 2. Keep a separate list of interesting commits. Drop items from it when they are dropped from the queue, or if they become UNINTERESTING. This again suffers from extra complexity to maintain the list, not to mention CPU and memory. 3. Use a better data structure for the queue. This is something that could help the fix in fce87ae, because we order the queue by recency, and it is about inserting quickly in recency order. So a normal priority queue would help there. But here, we cannot disturb the order of the queue, which makes things harder. We really do need an auxiliary index to track the flag we care about, which is basically option (2) above. The "cache" trick is simple, and the numbers above show that it works well in practice. This is because the length of time it takes to find an interesting commit is proportional to the length of time it will remain cached (i.e., if we have to walk a long way to find it, it also means we have to pop a lot of elements in the queue until we get rid of it and have to find another interesting commit). The worst case is still quadratic, though. We could have `N` uninteresting commits at the front of the queue, followed by `N` interesting commits, where commit `i` has parent `i+N`. When we pop commit `i`, we will notice that the parent of the next commit, `i+1+N` is still interesting and cache it. But then handling commit `i+1`, we will mark its parent `i+1+N` uninteresting, and immediately invalidate our cache. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-17 22:11:04 +00:00
if (*interesting_cache) {
struct commit *commit = *interesting_cache;
if (!(commit->object.flags & UNINTERESTING))
return 0;
}
while (list) {
struct commit *commit = list->item;
list = list->next;
if (commit->object.flags & UNINTERESTING)
continue;
*interesting_cache = commit;
return 0;
}
return 1;
}
/*
* A definition of "relevant" commit that we can use to simplify limited graphs
* by eliminating side branches.
*
* A "relevant" commit is one that is !UNINTERESTING (ie we are including it
* in our list), or that is a specified BOTTOM commit. Then after computing
* a limited list, during processing we can generally ignore boundary merges
* coming from outside the graph, (ie from irrelevant parents), and treat
* those merges as if they were single-parent. TREESAME is defined to consider
* only relevant parents, if any. If we are TREESAME to our on-graph parents,
* we don't care if we were !TREESAME to non-graph parents.
*
* Treating bottom commits as relevant ensures that a limited graph's
* connection to the actual bottom commit is not viewed as a side branch, but
* treated as part of the graph. For example:
*
* ....Z...A---X---o---o---B
* . /
* W---Y
*
* When computing "A..B", the A-X connection is at least as important as
* Y-X, despite A being flagged UNINTERESTING.
*
* And when computing --ancestry-path "A..B", the A-X connection is more
* important than Y-X, despite both A and Y being flagged UNINTERESTING.
*/
static inline int relevant_commit(struct commit *commit)
{
return (commit->object.flags & (UNINTERESTING | BOTTOM)) != UNINTERESTING;
}
/*
* Return a single relevant commit from a parent list. If we are a TREESAME
* commit, and this selects one of our parents, then we can safely simplify to
* that parent.
*/
static struct commit *one_relevant_parent(const struct rev_info *revs,
struct commit_list *orig)
{
struct commit_list *list = orig;
struct commit *relevant = NULL;
if (!orig)
return NULL;
/*
* For 1-parent commits, or if first-parent-only, then return that
* first parent (even if not "relevant" by the above definition).
* TREESAME will have been set purely on that parent.
*/
if (revs->first_parent_only || !orig->next)
return orig->item;
/*
* For multi-parent commits, identify a sole relevant parent, if any.
* If we have only one relevant parent, then TREESAME will be set purely
* with regard to that parent, and we can simplify accordingly.
*
* If we have more than one relevant parent, or no relevant parents
* (and multiple irrelevant ones), then we can't select a parent here
* and return NULL.
*/
while (list) {
struct commit *commit = list->item;
list = list->next;
if (relevant_commit(commit)) {
if (relevant)
return NULL;
relevant = commit;
}
}
return relevant;
}
/*
* The goal is to get REV_TREE_NEW as the result only if the
* diff consists of all '+' (and no other changes), REV_TREE_OLD
* if the whole diff is removal of old data, and otherwise
* REV_TREE_DIFFERENT (of course if the trees are the same we
* want REV_TREE_SAME).
revision: quit pruning diff more quickly when possible When the revision traversal machinery is given a pathspec, we must compute the parent-diff for each commit to determine which ones are TREESAME. We set the QUICK diff flag to avoid looking at more entries than we need; we really just care whether there are any changes at all. But there is one case where we want to know a bit more: if --remove-empty is set, we care about finding cases where the change consists only of added entries (in which case we may prune the parent in try_to_simplify_commit()). To cover that case, our file_add_remove() callback does not quit the diff upon seeing an added entry; it keeps looking for other types of entries. But this means when --remove-empty is not set (and it is not by default), we compute more of the diff than is necessary. You can see this in a pathological case where a commit adds a very large number of entries, and we limit based on a broad pathspec. E.g.: perl -e ' chomp(my $blob = `git hash-object -w --stdin </dev/null`); for my $a (1..1000) { for my $b (1..1000) { print "100644 $blob\t$a/$b\n"; } } ' | git update-index --index-info git commit -qm add git rev-list HEAD -- . This case takes about 100ms now, but after this patch only needs 6ms. That's not a huge improvement, but it's easy to get and it protects us against even more pathological cases (e.g., going from 1 million to 10 million files would take ten times as long with the current code, but not increase at all after this patch). This is reported to minorly speed-up pathspec limiting in real world repositories (like the 100-million-file Windows repository), but probably won't make a noticeable difference outside of pathological setups. This patch actually covers the case without --remove-empty, and the case where we see only deletions. See the in-code comment for details. Note that we have to add a new member to the diff_options struct so that our callback can see the value of revs->remove_empty_trees. This callback parameter could be passed to the "add_remove" and "change" callbacks, but there's not much point. They already receive the diff_options struct, and doing it this way avoids having to update the function signature of the other callbacks (arguably the format_callback and output_prefix functions could benefit from the same simplification). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-13 15:27:45 +00:00
*
* The only time we care about the distinction is when
* remove_empty_trees is in effect, in which case we care only about
* whether the whole change is REV_TREE_NEW, or if there's another type
* of change. Which means we can stop the diff early in either of these
* cases:
*
* 1. We're not using remove_empty_trees at all.
*
* 2. We saw anything except REV_TREE_NEW.
*/
static int tree_difference = REV_TREE_SAME;
static void file_add_remove(struct diff_options *options,
int addremove, unsigned mode,
const struct object_id *oid,
int oid_valid,
const char *fullpath, unsigned dirty_submodule)
{
int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
revision: quit pruning diff more quickly when possible When the revision traversal machinery is given a pathspec, we must compute the parent-diff for each commit to determine which ones are TREESAME. We set the QUICK diff flag to avoid looking at more entries than we need; we really just care whether there are any changes at all. But there is one case where we want to know a bit more: if --remove-empty is set, we care about finding cases where the change consists only of added entries (in which case we may prune the parent in try_to_simplify_commit()). To cover that case, our file_add_remove() callback does not quit the diff upon seeing an added entry; it keeps looking for other types of entries. But this means when --remove-empty is not set (and it is not by default), we compute more of the diff than is necessary. You can see this in a pathological case where a commit adds a very large number of entries, and we limit based on a broad pathspec. E.g.: perl -e ' chomp(my $blob = `git hash-object -w --stdin </dev/null`); for my $a (1..1000) { for my $b (1..1000) { print "100644 $blob\t$a/$b\n"; } } ' | git update-index --index-info git commit -qm add git rev-list HEAD -- . This case takes about 100ms now, but after this patch only needs 6ms. That's not a huge improvement, but it's easy to get and it protects us against even more pathological cases (e.g., going from 1 million to 10 million files would take ten times as long with the current code, but not increase at all after this patch). This is reported to minorly speed-up pathspec limiting in real world repositories (like the 100-million-file Windows repository), but probably won't make a noticeable difference outside of pathological setups. This patch actually covers the case without --remove-empty, and the case where we see only deletions. See the in-code comment for details. Note that we have to add a new member to the diff_options struct so that our callback can see the value of revs->remove_empty_trees. This callback parameter could be passed to the "add_remove" and "change" callbacks, but there's not much point. They already receive the diff_options struct, and doing it this way avoids having to update the function signature of the other callbacks (arguably the format_callback and output_prefix functions could benefit from the same simplification). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-13 15:27:45 +00:00
struct rev_info *revs = options->change_fn_data;
tree_difference |= diff;
revision: quit pruning diff more quickly when possible When the revision traversal machinery is given a pathspec, we must compute the parent-diff for each commit to determine which ones are TREESAME. We set the QUICK diff flag to avoid looking at more entries than we need; we really just care whether there are any changes at all. But there is one case where we want to know a bit more: if --remove-empty is set, we care about finding cases where the change consists only of added entries (in which case we may prune the parent in try_to_simplify_commit()). To cover that case, our file_add_remove() callback does not quit the diff upon seeing an added entry; it keeps looking for other types of entries. But this means when --remove-empty is not set (and it is not by default), we compute more of the diff than is necessary. You can see this in a pathological case where a commit adds a very large number of entries, and we limit based on a broad pathspec. E.g.: perl -e ' chomp(my $blob = `git hash-object -w --stdin </dev/null`); for my $a (1..1000) { for my $b (1..1000) { print "100644 $blob\t$a/$b\n"; } } ' | git update-index --index-info git commit -qm add git rev-list HEAD -- . This case takes about 100ms now, but after this patch only needs 6ms. That's not a huge improvement, but it's easy to get and it protects us against even more pathological cases (e.g., going from 1 million to 10 million files would take ten times as long with the current code, but not increase at all after this patch). This is reported to minorly speed-up pathspec limiting in real world repositories (like the 100-million-file Windows repository), but probably won't make a noticeable difference outside of pathological setups. This patch actually covers the case without --remove-empty, and the case where we see only deletions. See the in-code comment for details. Note that we have to add a new member to the diff_options struct so that our callback can see the value of revs->remove_empty_trees. This callback parameter could be passed to the "add_remove" and "change" callbacks, but there's not much point. They already receive the diff_options struct, and doing it this way avoids having to update the function signature of the other callbacks (arguably the format_callback and output_prefix functions could benefit from the same simplification). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-13 15:27:45 +00:00
if (!revs->remove_empty_trees || tree_difference != REV_TREE_NEW)
diff: make struct diff_flags members lowercase Now that the flags stored in struct diff_flags are being accessed directly and not through macros, change all struct members from being uppercase to lowercase. This conversion is done using the following semantic patch: @@ expression E; @@ - E.RECURSIVE + E.recursive @@ expression E; @@ - E.TREE_IN_RECURSIVE + E.tree_in_recursive @@ expression E; @@ - E.BINARY + E.binary @@ expression E; @@ - E.TEXT + E.text @@ expression E; @@ - E.FULL_INDEX + E.full_index @@ expression E; @@ - E.SILENT_ON_REMOVE + E.silent_on_remove @@ expression E; @@ - E.FIND_COPIES_HARDER + E.find_copies_harder @@ expression E; @@ - E.FOLLOW_RENAMES + E.follow_renames @@ expression E; @@ - E.RENAME_EMPTY + E.rename_empty @@ expression E; @@ - E.HAS_CHANGES + E.has_changes @@ expression E; @@ - E.QUICK + E.quick @@ expression E; @@ - E.NO_INDEX + E.no_index @@ expression E; @@ - E.ALLOW_EXTERNAL + E.allow_external @@ expression E; @@ - E.EXIT_WITH_STATUS + E.exit_with_status @@ expression E; @@ - E.REVERSE_DIFF + E.reverse_diff @@ expression E; @@ - E.CHECK_FAILED + E.check_failed @@ expression E; @@ - E.RELATIVE_NAME + E.relative_name @@ expression E; @@ - E.IGNORE_SUBMODULES + E.ignore_submodules @@ expression E; @@ - E.DIRSTAT_CUMULATIVE + E.dirstat_cumulative @@ expression E; @@ - E.DIRSTAT_BY_FILE + E.dirstat_by_file @@ expression E; @@ - E.ALLOW_TEXTCONV + E.allow_textconv @@ expression E; @@ - E.TEXTCONV_SET_VIA_CMDLINE + E.textconv_set_via_cmdline @@ expression E; @@ - E.DIFF_FROM_CONTENTS + E.diff_from_contents @@ expression E; @@ - E.DIRTY_SUBMODULES + E.dirty_submodules @@ expression E; @@ - E.IGNORE_UNTRACKED_IN_SUBMODULES + E.ignore_untracked_in_submodules @@ expression E; @@ - E.IGNORE_DIRTY_SUBMODULES + E.ignore_dirty_submodules @@ expression E; @@ - E.OVERRIDE_SUBMODULE_CONFIG + E.override_submodule_config @@ expression E; @@ - E.DIRSTAT_BY_LINE + E.dirstat_by_line @@ expression E; @@ - E.FUNCCONTEXT + E.funccontext @@ expression E; @@ - E.PICKAXE_IGNORE_CASE + E.pickaxe_ignore_case @@ expression E; @@ - E.DEFAULT_FOLLOW_RENAMES + E.default_follow_renames Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-31 18:19:11 +00:00
options->flags.has_changes = 1;
}
static void file_change(struct diff_options *options,
unsigned old_mode, unsigned new_mode,
const struct object_id *old_oid,
const struct object_id *new_oid,
int old_oid_valid, int new_oid_valid,
const char *fullpath,
unsigned old_dirty_submodule, unsigned new_dirty_submodule)
{
tree_difference = REV_TREE_DIFFERENT;
diff: make struct diff_flags members lowercase Now that the flags stored in struct diff_flags are being accessed directly and not through macros, change all struct members from being uppercase to lowercase. This conversion is done using the following semantic patch: @@ expression E; @@ - E.RECURSIVE + E.recursive @@ expression E; @@ - E.TREE_IN_RECURSIVE + E.tree_in_recursive @@ expression E; @@ - E.BINARY + E.binary @@ expression E; @@ - E.TEXT + E.text @@ expression E; @@ - E.FULL_INDEX + E.full_index @@ expression E; @@ - E.SILENT_ON_REMOVE + E.silent_on_remove @@ expression E; @@ - E.FIND_COPIES_HARDER + E.find_copies_harder @@ expression E; @@ - E.FOLLOW_RENAMES + E.follow_renames @@ expression E; @@ - E.RENAME_EMPTY + E.rename_empty @@ expression E; @@ - E.HAS_CHANGES + E.has_changes @@ expression E; @@ - E.QUICK + E.quick @@ expression E; @@ - E.NO_INDEX + E.no_index @@ expression E; @@ - E.ALLOW_EXTERNAL + E.allow_external @@ expression E; @@ - E.EXIT_WITH_STATUS + E.exit_with_status @@ expression E; @@ - E.REVERSE_DIFF + E.reverse_diff @@ expression E; @@ - E.CHECK_FAILED + E.check_failed @@ expression E; @@ - E.RELATIVE_NAME + E.relative_name @@ expression E; @@ - E.IGNORE_SUBMODULES + E.ignore_submodules @@ expression E; @@ - E.DIRSTAT_CUMULATIVE + E.dirstat_cumulative @@ expression E; @@ - E.DIRSTAT_BY_FILE + E.dirstat_by_file @@ expression E; @@ - E.ALLOW_TEXTCONV + E.allow_textconv @@ expression E; @@ - E.TEXTCONV_SET_VIA_CMDLINE + E.textconv_set_via_cmdline @@ expression E; @@ - E.DIFF_FROM_CONTENTS + E.diff_from_contents @@ expression E; @@ - E.DIRTY_SUBMODULES + E.dirty_submodules @@ expression E; @@ - E.IGNORE_UNTRACKED_IN_SUBMODULES + E.ignore_untracked_in_submodules @@ expression E; @@ - E.IGNORE_DIRTY_SUBMODULES + E.ignore_dirty_submodules @@ expression E; @@ - E.OVERRIDE_SUBMODULE_CONFIG + E.override_submodule_config @@ expression E; @@ - E.DIRSTAT_BY_LINE + E.dirstat_by_line @@ expression E; @@ - E.FUNCCONTEXT + E.funccontext @@ expression E; @@ - E.PICKAXE_IGNORE_CASE + E.pickaxe_ignore_case @@ expression E; @@ - E.DEFAULT_FOLLOW_RENAMES + E.default_follow_renames Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-31 18:19:11 +00:00
options->flags.has_changes = 1;
}
static int bloom_filter_atexit_registered;
static unsigned int count_bloom_filter_maybe;
static unsigned int count_bloom_filter_definitely_not;
static unsigned int count_bloom_filter_false_positive;
static unsigned int count_bloom_filter_not_present;
static void trace2_bloom_filter_statistics_atexit(void)
{
struct json_writer jw = JSON_WRITER_INIT;
jw_object_begin(&jw, 0);
jw_object_intmax(&jw, "filter_not_present", count_bloom_filter_not_present);
jw_object_intmax(&jw, "maybe", count_bloom_filter_maybe);
jw_object_intmax(&jw, "definitely_not", count_bloom_filter_definitely_not);
jw_object_intmax(&jw, "false_positive", count_bloom_filter_false_positive);
jw_end(&jw);
trace2_data_json("bloom", the_repository, "statistics", &jw);
jw_release(&jw);
}
static int forbid_bloom_filters(struct pathspec *spec)
{
if (spec->has_wildcard)
return 1;
if (spec->nr > 1)
return 1;
if (spec->magic & ~PATHSPEC_LITERAL)
return 1;
if (spec->nr && (spec->items[0].magic & ~PATHSPEC_LITERAL))
return 1;
return 0;
}
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
static void prepare_to_use_bloom_filter(struct rev_info *revs)
{
struct pathspec_item *pi;
char *path_alloc = NULL;
commit-graph: check all leading directories in changed path Bloom filters The file 'dir/subdir/file' can only be modified if its leading directories 'dir' and 'dir/subdir' are modified as well. So when checking modified path Bloom filters looking for commits modifying a path with multiple path components, then check not only the full path in the Bloom filters, but all its leading directories as well. Take care to check these paths in "deepest first" order, because it's the full path that is least likely to be modified, and the Bloom filter queries can short circuit sooner. This can significantly reduce the average false positive rate, by about an order of magnitude or three(!), and can further speed up pathspec-limited revision walks. The table below compares the average false positive rate and runtime of git rev-list HEAD -- "$path" before and after this change for 5000+ randomly* selected paths from each repository: Average false Average Average positive rate runtime runtime before after before after difference ------------------------------------------------------------------ git 3.220% 0.7853% 0.0558s 0.0387s -30.6% linux 2.453% 0.0296% 0.1046s 0.0766s -26.8% tensorflow 2.536% 0.6977% 0.0594s 0.0420s -29.2% *Path selection was done with the following pipeline: git ls-tree -r --name-only HEAD | sort -R | head -n 5000 The improvements in runtime are much smaller than the improvements in average false positive rate, as we are clearly reaching diminishing returns here. However, all these timings depend on that accessing tree objects is reasonably fast (warm caches). If we had a partial clone and the tree objects had to be fetched from a promisor remote, e.g.: $ git clone --filter=tree:0 --bare file://.../webkit.git webkit.notrees.git $ git -C webkit.git -c core.modifiedPathBloomFilters=1 \ commit-graph write --reachable $ cp webkit.git/objects/info/commit-graph webkit.notrees.git/objects/info/ $ git -C webkit.notrees.git -c core.modifiedPathBloomFilters=1 \ rev-list HEAD -- "$path" then checking all leading path component can reduce the runtime from over an hour to a few seconds (and this is with the clone and the promisor on the same machine). This adjusts the tracing values in t4216-log-bloom.sh, which provides a concrete way to notice the improvement. Helped-by: Taylor Blau <me@ttaylorr.com> Helped-by: René Scharfe <l.s.r@web.de> Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-01 13:27:30 +00:00
const char *path, *p;
size_t len;
int path_component_nr = 1;
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
if (!revs->commits)
return;
if (forbid_bloom_filters(&revs->prune_data))
return;
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
repo_parse_commit(revs->repo, revs->commits->item);
commit-graph: introduce 'get_bloom_filter_settings()' Many places in the code often need a pointer to the commit-graph's 'struct bloom_filter_settings', in which case they often take the value from the top-most commit-graph. In the non-split case, this works as expected. In the split case, however, things get a little tricky. Not all layers in a chain of incremental commit-graphs are required to themselves have Bloom data, and so whether or not some part of the code uses Bloom filters depends entirely on whether or not the top-most level of the commit-graph chain has Bloom filters. This has been the behavior since Bloom filters were introduced, and has been codified into the tests since a759bfa9ee (t4216: add end to end tests for git log with Bloom filters, 2020-04-06). In fact, t4216.130 requires that Bloom filters are not used in exactly the case described earlier. There is no reason that this needs to be the case, since it is perfectly valid for commits in an earlier layer to have Bloom filters when commits in a newer layer do not. Since Bloom settings are guaranteed in practice to be the same for any layer in a chain that has Bloom data, it is sufficient to traverse the '->base_graph' pointer until either (1) a non-null 'struct bloom_filter_settings *' is found, or (2) until we are at the root of the commit-graph chain. Introduce a 'get_bloom_filter_settings()' function that does just this, and use it instead of purely dereferencing the top-most graph's '->bloom_filter_settings' pointer. While we're at it, add an additional test in t5324 to guard against code in the commit-graph writing machinery that doesn't correctly handle a NULL 'struct bloom_filter *'. Co-authored-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-09 15:22:44 +00:00
revs->bloom_filter_settings = get_bloom_filter_settings(revs->repo);
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
if (!revs->bloom_filter_settings)
return;
line-log: integrate with changed-path Bloom filters The previous changes to the line-log machinery focused on making the first result appear faster. This was achieved by no longer walking the entire commit history before returning the early results. There is still another way to improve the performance: walk most commits much faster. Let's use the changed-path Bloom filters to reduce time spent computing diffs. Since the line-log computation requires opening blobs and checking the content-diff, there is still a lot of necessary computation that cannot be replaced with changed-path Bloom filters. The part that we can reduce is most effective when checking the history of a file that is deep in several directories and those directories are modified frequently. In this case, the computation to check if a commit is TREESAME to its first parent takes a large fraction of the time. That is ripe for improvement with changed-path Bloom filters. We must ensure that prepare_to_use_bloom_filters() is called in revision.c so that the bloom_filter_settings are loaded into the struct rev_info from the commit-graph. Of course, some cases are still forbidden, but in the line-log case the pathspec is provided in a different way than normal. Since multiple paths and segments could be requested, we compute the struct bloom_key data dynamically during the commit walk. This could likely be improved, but adds code complexity that is not valuable at this time. There are two cases to care about: merge commits and "ordinary" commits. Merge commits have multiple parents, but if we are TREESAME to our first parent in every range, then pass the blame for all ranges to the first parent. Ordinary commits have the same condition, but each is done slightly differently in the process_ranges_[merge|ordinary]_commit() methods. By checking if the changed-path Bloom filter can guarantee TREESAME, we can avoid that tree-diff cost. If the filter says "probably changed", then we need to run the tree-diff and then the blob-diff if there was a real edit. The Linux kernel repository is a good testing ground for the performance improvements claimed here. There are two different cases to test. The first is the "entire history" case, where we output the entire history to /dev/null to see how long it would take to compute the full line-log history. The second is the "first result" case, where we find how long it takes to show the first value, which is an indicator of how quickly a user would see responses when waiting at a terminal. To test, I selected the paths that were changed most frequently in the top 10,000 commits using this command (stolen from StackOverflow [1]): git log --pretty=format: --name-only -n 10000 | sort | \ uniq -c | sort -rg | head -10 which results in 121 MAINTAINERS 63 fs/namei.c 60 arch/x86/kvm/cpuid.c 59 fs/io_uring.c 58 arch/x86/kvm/vmx/vmx.c 51 arch/x86/kvm/x86.c 45 arch/x86/kvm/svm.c 42 fs/btrfs/disk-io.c 42 Documentation/scsi/index.rst (along with a bogus first result). It appears that the path arch/x86/kvm/svm.c was renamed, so we ignore that entry. This leaves the following results for the real command time: | | Entire History | First Result | | Path | Before | After | Before | After | |------------------------------|--------|--------|--------|--------| | MAINTAINERS | 4.26 s | 3.87 s | 0.41 s | 0.39 s | | fs/namei.c | 1.99 s | 0.99 s | 0.42 s | 0.21 s | | arch/x86/kvm/cpuid.c | 5.28 s | 1.12 s | 0.16 s | 0.09 s | | fs/io_uring.c | 4.34 s | 0.99 s | 0.94 s | 0.27 s | | arch/x86/kvm/vmx/vmx.c | 5.01 s | 1.34 s | 0.21 s | 0.12 s | | arch/x86/kvm/x86.c | 2.24 s | 1.18 s | 0.21 s | 0.14 s | | fs/btrfs/disk-io.c | 1.82 s | 1.01 s | 0.06 s | 0.05 s | | Documentation/scsi/index.rst | 3.30 s | 0.89 s | 1.46 s | 0.03 s | It is worth noting that the least speedup comes for the MAINTAINERS file which is * edited frequently, * low in the directory heirarchy, and * quite a large file. All of those points lead to spending more time doing the blob diff and less time doing the tree diff. Still, we see some improvement in that case and significant improvement in other cases. A 2-4x speedup is likely the more typical case as opposed to the small 5% change for that file. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-11 11:56:19 +00:00
if (!revs->pruning.pathspec.nr)
return;
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
pi = &revs->pruning.pathspec.items[0];
/* remove single trailing slash from path, if needed */
revision: avoid out-of-bounds read/write on empty pathspec Running t4216 with ASan results in it complaining of an out-of-bounds read in prepare_to_use_bloom_filter(). The issue is this code to strip a trailing slash: last_index = pi->len - 1; if (pi->match[last_index] == '/') { because we have no guarantee that pi->len isn't zero. This can happen if the pathspec is ".", as we translate that to an empty string. And if that read of random memory does trigger the conditional, we'd then do an out-of-bounds write: path_alloc = xstrdup(pi->match); path_alloc[last_index] = '\0'; Let's make sure to check the length before subtracting. Note that for an empty pathspec, we'd end up bailing from the function a few lines later, which makes it tempting to just: if (!pi->len) return; early here. But our code here is stripping a trailing slash, and we need to check for emptiness after stripping that slash, too. So we'd have two blocks, which would require repeating some cleanup code. Instead, just skip the trailing-slash for an empty string. Setting last_index at all in the case is awkward since it will have a nonsense value (and it uses an "int", which is a too-small type for a string anyway). So while we're here, let's: - drop last_index entirely; it's only used in two spots right next to each other and writing out "pi->len - 1" in both is actually easier to follow - use xmemdupz() to duplicate the string. This is slightly more efficient, but more importantly makes the intent more clear by allocating the correct-sized substring in the first place. It also eliminates any question of whether path_alloc is as long as pi->match (which it would not be if pi->match has any embedded NULs, though in practice this is probably impossible). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-04 07:46:52 +00:00
if (pi->len > 0 && pi->match[pi->len - 1] == '/') {
path_alloc = xmemdupz(pi->match, pi->len - 1);
path = path_alloc;
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
} else
path = pi->match;
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
len = strlen(path);
if (!len) {
revs->bloom_filter_settings = NULL;
free(path_alloc);
return;
}
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
commit-graph: check all leading directories in changed path Bloom filters The file 'dir/subdir/file' can only be modified if its leading directories 'dir' and 'dir/subdir' are modified as well. So when checking modified path Bloom filters looking for commits modifying a path with multiple path components, then check not only the full path in the Bloom filters, but all its leading directories as well. Take care to check these paths in "deepest first" order, because it's the full path that is least likely to be modified, and the Bloom filter queries can short circuit sooner. This can significantly reduce the average false positive rate, by about an order of magnitude or three(!), and can further speed up pathspec-limited revision walks. The table below compares the average false positive rate and runtime of git rev-list HEAD -- "$path" before and after this change for 5000+ randomly* selected paths from each repository: Average false Average Average positive rate runtime runtime before after before after difference ------------------------------------------------------------------ git 3.220% 0.7853% 0.0558s 0.0387s -30.6% linux 2.453% 0.0296% 0.1046s 0.0766s -26.8% tensorflow 2.536% 0.6977% 0.0594s 0.0420s -29.2% *Path selection was done with the following pipeline: git ls-tree -r --name-only HEAD | sort -R | head -n 5000 The improvements in runtime are much smaller than the improvements in average false positive rate, as we are clearly reaching diminishing returns here. However, all these timings depend on that accessing tree objects is reasonably fast (warm caches). If we had a partial clone and the tree objects had to be fetched from a promisor remote, e.g.: $ git clone --filter=tree:0 --bare file://.../webkit.git webkit.notrees.git $ git -C webkit.git -c core.modifiedPathBloomFilters=1 \ commit-graph write --reachable $ cp webkit.git/objects/info/commit-graph webkit.notrees.git/objects/info/ $ git -C webkit.notrees.git -c core.modifiedPathBloomFilters=1 \ rev-list HEAD -- "$path" then checking all leading path component can reduce the runtime from over an hour to a few seconds (and this is with the clone and the promisor on the same machine). This adjusts the tracing values in t4216-log-bloom.sh, which provides a concrete way to notice the improvement. Helped-by: Taylor Blau <me@ttaylorr.com> Helped-by: René Scharfe <l.s.r@web.de> Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-01 13:27:30 +00:00
p = path;
while (*p) {
/*
* At this point, the path is normalized to use Unix-style
* path separators. This is required due to how the
* changed-path Bloom filters store the paths.
*/
if (*p == '/')
path_component_nr++;
p++;
}
revs->bloom_keys_nr = path_component_nr;
ALLOC_ARRAY(revs->bloom_keys, revs->bloom_keys_nr);
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
commit-graph: check all leading directories in changed path Bloom filters The file 'dir/subdir/file' can only be modified if its leading directories 'dir' and 'dir/subdir' are modified as well. So when checking modified path Bloom filters looking for commits modifying a path with multiple path components, then check not only the full path in the Bloom filters, but all its leading directories as well. Take care to check these paths in "deepest first" order, because it's the full path that is least likely to be modified, and the Bloom filter queries can short circuit sooner. This can significantly reduce the average false positive rate, by about an order of magnitude or three(!), and can further speed up pathspec-limited revision walks. The table below compares the average false positive rate and runtime of git rev-list HEAD -- "$path" before and after this change for 5000+ randomly* selected paths from each repository: Average false Average Average positive rate runtime runtime before after before after difference ------------------------------------------------------------------ git 3.220% 0.7853% 0.0558s 0.0387s -30.6% linux 2.453% 0.0296% 0.1046s 0.0766s -26.8% tensorflow 2.536% 0.6977% 0.0594s 0.0420s -29.2% *Path selection was done with the following pipeline: git ls-tree -r --name-only HEAD | sort -R | head -n 5000 The improvements in runtime are much smaller than the improvements in average false positive rate, as we are clearly reaching diminishing returns here. However, all these timings depend on that accessing tree objects is reasonably fast (warm caches). If we had a partial clone and the tree objects had to be fetched from a promisor remote, e.g.: $ git clone --filter=tree:0 --bare file://.../webkit.git webkit.notrees.git $ git -C webkit.git -c core.modifiedPathBloomFilters=1 \ commit-graph write --reachable $ cp webkit.git/objects/info/commit-graph webkit.notrees.git/objects/info/ $ git -C webkit.notrees.git -c core.modifiedPathBloomFilters=1 \ rev-list HEAD -- "$path" then checking all leading path component can reduce the runtime from over an hour to a few seconds (and this is with the clone and the promisor on the same machine). This adjusts the tracing values in t4216-log-bloom.sh, which provides a concrete way to notice the improvement. Helped-by: Taylor Blau <me@ttaylorr.com> Helped-by: René Scharfe <l.s.r@web.de> Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-01 13:27:30 +00:00
fill_bloom_key(path, len, &revs->bloom_keys[0],
revs->bloom_filter_settings);
path_component_nr = 1;
p = path + len - 1;
while (p > path) {
if (*p == '/')
fill_bloom_key(path, p - path,
&revs->bloom_keys[path_component_nr++],
revs->bloom_filter_settings);
p--;
}
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
if (trace2_is_enabled() && !bloom_filter_atexit_registered) {
atexit(trace2_bloom_filter_statistics_atexit);
bloom_filter_atexit_registered = 1;
}
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
free(path_alloc);
}
static int check_maybe_different_in_bloom_filter(struct rev_info *revs,
struct commit *commit)
{
struct bloom_filter *filter;
commit-graph: check all leading directories in changed path Bloom filters The file 'dir/subdir/file' can only be modified if its leading directories 'dir' and 'dir/subdir' are modified as well. So when checking modified path Bloom filters looking for commits modifying a path with multiple path components, then check not only the full path in the Bloom filters, but all its leading directories as well. Take care to check these paths in "deepest first" order, because it's the full path that is least likely to be modified, and the Bloom filter queries can short circuit sooner. This can significantly reduce the average false positive rate, by about an order of magnitude or three(!), and can further speed up pathspec-limited revision walks. The table below compares the average false positive rate and runtime of git rev-list HEAD -- "$path" before and after this change for 5000+ randomly* selected paths from each repository: Average false Average Average positive rate runtime runtime before after before after difference ------------------------------------------------------------------ git 3.220% 0.7853% 0.0558s 0.0387s -30.6% linux 2.453% 0.0296% 0.1046s 0.0766s -26.8% tensorflow 2.536% 0.6977% 0.0594s 0.0420s -29.2% *Path selection was done with the following pipeline: git ls-tree -r --name-only HEAD | sort -R | head -n 5000 The improvements in runtime are much smaller than the improvements in average false positive rate, as we are clearly reaching diminishing returns here. However, all these timings depend on that accessing tree objects is reasonably fast (warm caches). If we had a partial clone and the tree objects had to be fetched from a promisor remote, e.g.: $ git clone --filter=tree:0 --bare file://.../webkit.git webkit.notrees.git $ git -C webkit.git -c core.modifiedPathBloomFilters=1 \ commit-graph write --reachable $ cp webkit.git/objects/info/commit-graph webkit.notrees.git/objects/info/ $ git -C webkit.notrees.git -c core.modifiedPathBloomFilters=1 \ rev-list HEAD -- "$path" then checking all leading path component can reduce the runtime from over an hour to a few seconds (and this is with the clone and the promisor on the same machine). This adjusts the tracing values in t4216-log-bloom.sh, which provides a concrete way to notice the improvement. Helped-by: Taylor Blau <me@ttaylorr.com> Helped-by: René Scharfe <l.s.r@web.de> Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-01 13:27:30 +00:00
int result = 1, j;
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
if (!revs->repo->objects->commit_graph)
return -1;
if (commit_graph_generation(commit) == GENERATION_NUMBER_INFINITY)
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
return -1;
filter = get_bloom_filter(revs->repo, commit);
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
if (!filter) {
count_bloom_filter_not_present++;
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
return -1;
}
commit-graph: check all leading directories in changed path Bloom filters The file 'dir/subdir/file' can only be modified if its leading directories 'dir' and 'dir/subdir' are modified as well. So when checking modified path Bloom filters looking for commits modifying a path with multiple path components, then check not only the full path in the Bloom filters, but all its leading directories as well. Take care to check these paths in "deepest first" order, because it's the full path that is least likely to be modified, and the Bloom filter queries can short circuit sooner. This can significantly reduce the average false positive rate, by about an order of magnitude or three(!), and can further speed up pathspec-limited revision walks. The table below compares the average false positive rate and runtime of git rev-list HEAD -- "$path" before and after this change for 5000+ randomly* selected paths from each repository: Average false Average Average positive rate runtime runtime before after before after difference ------------------------------------------------------------------ git 3.220% 0.7853% 0.0558s 0.0387s -30.6% linux 2.453% 0.0296% 0.1046s 0.0766s -26.8% tensorflow 2.536% 0.6977% 0.0594s 0.0420s -29.2% *Path selection was done with the following pipeline: git ls-tree -r --name-only HEAD | sort -R | head -n 5000 The improvements in runtime are much smaller than the improvements in average false positive rate, as we are clearly reaching diminishing returns here. However, all these timings depend on that accessing tree objects is reasonably fast (warm caches). If we had a partial clone and the tree objects had to be fetched from a promisor remote, e.g.: $ git clone --filter=tree:0 --bare file://.../webkit.git webkit.notrees.git $ git -C webkit.git -c core.modifiedPathBloomFilters=1 \ commit-graph write --reachable $ cp webkit.git/objects/info/commit-graph webkit.notrees.git/objects/info/ $ git -C webkit.notrees.git -c core.modifiedPathBloomFilters=1 \ rev-list HEAD -- "$path" then checking all leading path component can reduce the runtime from over an hour to a few seconds (and this is with the clone and the promisor on the same machine). This adjusts the tracing values in t4216-log-bloom.sh, which provides a concrete way to notice the improvement. Helped-by: Taylor Blau <me@ttaylorr.com> Helped-by: René Scharfe <l.s.r@web.de> Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-01 13:27:30 +00:00
for (j = 0; result && j < revs->bloom_keys_nr; j++) {
result = bloom_filter_contains(filter,
&revs->bloom_keys[j],
revs->bloom_filter_settings);
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
}
if (result)
count_bloom_filter_maybe++;
else
count_bloom_filter_definitely_not++;
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
return result;
}
static int rev_compare_tree(struct rev_info *revs,
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
struct commit *parent, struct commit *commit, int nth_parent)
{
struct tree *t1 = get_commit_tree(parent);
struct tree *t2 = get_commit_tree(commit);
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
int bloom_ret = 1;
if (!t1)
return REV_TREE_NEW;
if (!t2)
return REV_TREE_OLD;
if (revs->simplify_by_decoration) {
/*
* If we are simplifying by decoration, then the commit
* is worth showing if it has a tag pointing at it.
*/
if (get_name_decoration(&commit->object))
return REV_TREE_DIFFERENT;
/*
* A commit that is not pointed by a tag is uninteresting
* if we are not limited by path. This means that you will
* see the usual "commits that touch the paths" plus any
* tagged commit by specifying both --simplify-by-decoration
* and pathspec.
*/
if (!revs->prune_data.nr)
return REV_TREE_SAME;
}
commit-graph: check all leading directories in changed path Bloom filters The file 'dir/subdir/file' can only be modified if its leading directories 'dir' and 'dir/subdir' are modified as well. So when checking modified path Bloom filters looking for commits modifying a path with multiple path components, then check not only the full path in the Bloom filters, but all its leading directories as well. Take care to check these paths in "deepest first" order, because it's the full path that is least likely to be modified, and the Bloom filter queries can short circuit sooner. This can significantly reduce the average false positive rate, by about an order of magnitude or three(!), and can further speed up pathspec-limited revision walks. The table below compares the average false positive rate and runtime of git rev-list HEAD -- "$path" before and after this change for 5000+ randomly* selected paths from each repository: Average false Average Average positive rate runtime runtime before after before after difference ------------------------------------------------------------------ git 3.220% 0.7853% 0.0558s 0.0387s -30.6% linux 2.453% 0.0296% 0.1046s 0.0766s -26.8% tensorflow 2.536% 0.6977% 0.0594s 0.0420s -29.2% *Path selection was done with the following pipeline: git ls-tree -r --name-only HEAD | sort -R | head -n 5000 The improvements in runtime are much smaller than the improvements in average false positive rate, as we are clearly reaching diminishing returns here. However, all these timings depend on that accessing tree objects is reasonably fast (warm caches). If we had a partial clone and the tree objects had to be fetched from a promisor remote, e.g.: $ git clone --filter=tree:0 --bare file://.../webkit.git webkit.notrees.git $ git -C webkit.git -c core.modifiedPathBloomFilters=1 \ commit-graph write --reachable $ cp webkit.git/objects/info/commit-graph webkit.notrees.git/objects/info/ $ git -C webkit.notrees.git -c core.modifiedPathBloomFilters=1 \ rev-list HEAD -- "$path" then checking all leading path component can reduce the runtime from over an hour to a few seconds (and this is with the clone and the promisor on the same machine). This adjusts the tracing values in t4216-log-bloom.sh, which provides a concrete way to notice the improvement. Helped-by: Taylor Blau <me@ttaylorr.com> Helped-by: René Scharfe <l.s.r@web.de> Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-01 13:27:30 +00:00
if (revs->bloom_keys_nr && !nth_parent) {
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
bloom_ret = check_maybe_different_in_bloom_filter(revs, commit);
if (bloom_ret == 0)
return REV_TREE_SAME;
}
tree_difference = REV_TREE_SAME;
diff: make struct diff_flags members lowercase Now that the flags stored in struct diff_flags are being accessed directly and not through macros, change all struct members from being uppercase to lowercase. This conversion is done using the following semantic patch: @@ expression E; @@ - E.RECURSIVE + E.recursive @@ expression E; @@ - E.TREE_IN_RECURSIVE + E.tree_in_recursive @@ expression E; @@ - E.BINARY + E.binary @@ expression E; @@ - E.TEXT + E.text @@ expression E; @@ - E.FULL_INDEX + E.full_index @@ expression E; @@ - E.SILENT_ON_REMOVE + E.silent_on_remove @@ expression E; @@ - E.FIND_COPIES_HARDER + E.find_copies_harder @@ expression E; @@ - E.FOLLOW_RENAMES + E.follow_renames @@ expression E; @@ - E.RENAME_EMPTY + E.rename_empty @@ expression E; @@ - E.HAS_CHANGES + E.has_changes @@ expression E; @@ - E.QUICK + E.quick @@ expression E; @@ - E.NO_INDEX + E.no_index @@ expression E; @@ - E.ALLOW_EXTERNAL + E.allow_external @@ expression E; @@ - E.EXIT_WITH_STATUS + E.exit_with_status @@ expression E; @@ - E.REVERSE_DIFF + E.reverse_diff @@ expression E; @@ - E.CHECK_FAILED + E.check_failed @@ expression E; @@ - E.RELATIVE_NAME + E.relative_name @@ expression E; @@ - E.IGNORE_SUBMODULES + E.ignore_submodules @@ expression E; @@ - E.DIRSTAT_CUMULATIVE + E.dirstat_cumulative @@ expression E; @@ - E.DIRSTAT_BY_FILE + E.dirstat_by_file @@ expression E; @@ - E.ALLOW_TEXTCONV + E.allow_textconv @@ expression E; @@ - E.TEXTCONV_SET_VIA_CMDLINE + E.textconv_set_via_cmdline @@ expression E; @@ - E.DIFF_FROM_CONTENTS + E.diff_from_contents @@ expression E; @@ - E.DIRTY_SUBMODULES + E.dirty_submodules @@ expression E; @@ - E.IGNORE_UNTRACKED_IN_SUBMODULES + E.ignore_untracked_in_submodules @@ expression E; @@ - E.IGNORE_DIRTY_SUBMODULES + E.ignore_dirty_submodules @@ expression E; @@ - E.OVERRIDE_SUBMODULE_CONFIG + E.override_submodule_config @@ expression E; @@ - E.DIRSTAT_BY_LINE + E.dirstat_by_line @@ expression E; @@ - E.FUNCCONTEXT + E.funccontext @@ expression E; @@ - E.PICKAXE_IGNORE_CASE + E.pickaxe_ignore_case @@ expression E; @@ - E.DEFAULT_FOLLOW_RENAMES + E.default_follow_renames Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-31 18:19:11 +00:00
revs->pruning.flags.has_changes = 0;
diff_tree_oid(&t1->object.oid, &t2->object.oid, "", &revs->pruning);
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
if (!nth_parent)
if (bloom_ret == 1 && tree_difference == REV_TREE_SAME)
count_bloom_filter_false_positive++;
return tree_difference;
}
static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
{
struct tree *t1 = get_commit_tree(commit);
if (!t1)
return 0;
tree_difference = REV_TREE_SAME;
diff: make struct diff_flags members lowercase Now that the flags stored in struct diff_flags are being accessed directly and not through macros, change all struct members from being uppercase to lowercase. This conversion is done using the following semantic patch: @@ expression E; @@ - E.RECURSIVE + E.recursive @@ expression E; @@ - E.TREE_IN_RECURSIVE + E.tree_in_recursive @@ expression E; @@ - E.BINARY + E.binary @@ expression E; @@ - E.TEXT + E.text @@ expression E; @@ - E.FULL_INDEX + E.full_index @@ expression E; @@ - E.SILENT_ON_REMOVE + E.silent_on_remove @@ expression E; @@ - E.FIND_COPIES_HARDER + E.find_copies_harder @@ expression E; @@ - E.FOLLOW_RENAMES + E.follow_renames @@ expression E; @@ - E.RENAME_EMPTY + E.rename_empty @@ expression E; @@ - E.HAS_CHANGES + E.has_changes @@ expression E; @@ - E.QUICK + E.quick @@ expression E; @@ - E.NO_INDEX + E.no_index @@ expression E; @@ - E.ALLOW_EXTERNAL + E.allow_external @@ expression E; @@ - E.EXIT_WITH_STATUS + E.exit_with_status @@ expression E; @@ - E.REVERSE_DIFF + E.reverse_diff @@ expression E; @@ - E.CHECK_FAILED + E.check_failed @@ expression E; @@ - E.RELATIVE_NAME + E.relative_name @@ expression E; @@ - E.IGNORE_SUBMODULES + E.ignore_submodules @@ expression E; @@ - E.DIRSTAT_CUMULATIVE + E.dirstat_cumulative @@ expression E; @@ - E.DIRSTAT_BY_FILE + E.dirstat_by_file @@ expression E; @@ - E.ALLOW_TEXTCONV + E.allow_textconv @@ expression E; @@ - E.TEXTCONV_SET_VIA_CMDLINE + E.textconv_set_via_cmdline @@ expression E; @@ - E.DIFF_FROM_CONTENTS + E.diff_from_contents @@ expression E; @@ - E.DIRTY_SUBMODULES + E.dirty_submodules @@ expression E; @@ - E.IGNORE_UNTRACKED_IN_SUBMODULES + E.ignore_untracked_in_submodules @@ expression E; @@ - E.IGNORE_DIRTY_SUBMODULES + E.ignore_dirty_submodules @@ expression E; @@ - E.OVERRIDE_SUBMODULE_CONFIG + E.override_submodule_config @@ expression E; @@ - E.DIRSTAT_BY_LINE + E.dirstat_by_line @@ expression E; @@ - E.FUNCCONTEXT + E.funccontext @@ expression E; @@ - E.PICKAXE_IGNORE_CASE + E.pickaxe_ignore_case @@ expression E; @@ - E.DEFAULT_FOLLOW_RENAMES + E.default_follow_renames Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-31 18:19:11 +00:00
revs->pruning.flags.has_changes = 0;
diff_tree_oid(NULL, &t1->object.oid, "", &revs->pruning);
return tree_difference == REV_TREE_SAME;
}
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
struct treesame_state {
unsigned int nparents;
unsigned char treesame[FLEX_ARRAY];
};
static struct treesame_state *initialise_treesame(struct rev_info *revs, struct commit *commit)
{
unsigned n = commit_list_count(commit->parents);
struct treesame_state *st = xcalloc(1, st_add(sizeof(*st), n));
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
st->nparents = n;
add_decoration(&revs->treesame, &commit->object, st);
return st;
}
/*
* Must be called immediately after removing the nth_parent from a commit's
* parent list, if we are maintaining the per-parent treesame[] decoration.
* This does not recalculate the master TREESAME flag - update_treesame()
* should be called to update it after a sequence of treesame[] modifications
* that may have affected it.
*/
static int compact_treesame(struct rev_info *revs, struct commit *commit, unsigned nth_parent)
{
struct treesame_state *st;
int old_same;
if (!commit->parents) {
/*
* Have just removed the only parent from a non-merge.
* Different handling, as we lack decoration.
*/
if (nth_parent != 0)
die("compact_treesame %u", nth_parent);
old_same = !!(commit->object.flags & TREESAME);
if (rev_same_tree_as_empty(revs, commit))
commit->object.flags |= TREESAME;
else
commit->object.flags &= ~TREESAME;
return old_same;
}
st = lookup_decoration(&revs->treesame, &commit->object);
if (!st || nth_parent >= st->nparents)
die("compact_treesame %u", nth_parent);
old_same = st->treesame[nth_parent];
memmove(st->treesame + nth_parent,
st->treesame + nth_parent + 1,
st->nparents - nth_parent - 1);
/*
* If we've just become a non-merge commit, update TREESAME
* immediately, and remove the no-longer-needed decoration.
* If still a merge, defer update until update_treesame().
*/
if (--st->nparents == 1) {
if (commit->parents->next)
die("compact_treesame parents mismatch");
if (st->treesame[0] && revs->dense)
commit->object.flags |= TREESAME;
else
commit->object.flags &= ~TREESAME;
free(add_decoration(&revs->treesame, &commit->object, NULL));
}
return old_same;
}
static unsigned update_treesame(struct rev_info *revs, struct commit *commit)
{
if (commit->parents && commit->parents->next) {
unsigned n;
struct treesame_state *st;
struct commit_list *p;
unsigned relevant_parents;
unsigned relevant_change, irrelevant_change;
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
st = lookup_decoration(&revs->treesame, &commit->object);
if (!st)
die("update_treesame %s", oid_to_hex(&commit->object.oid));
relevant_parents = 0;
relevant_change = irrelevant_change = 0;
for (p = commit->parents, n = 0; p; n++, p = p->next) {
if (relevant_commit(p->item)) {
relevant_change |= !st->treesame[n];
relevant_parents++;
} else
irrelevant_change |= !st->treesame[n];
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
}
if (relevant_parents ? relevant_change : irrelevant_change)
commit->object.flags &= ~TREESAME;
else
commit->object.flags |= TREESAME;
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
}
return commit->object.flags & TREESAME;
}
static inline int limiting_can_increase_treesame(const struct rev_info *revs)
{
/*
* TREESAME is irrelevant unless prune && dense;
* if simplify_history is set, we can't have a mixture of TREESAME and
* !TREESAME INTERESTING parents (and we don't have treesame[]
* decoration anyway);
* if first_parent_only is set, then the TREESAME flag is locked
* against the first parent (and again we lack treesame[] decoration).
*/
return revs->prune && revs->dense &&
!revs->simplify_history &&
!revs->first_parent_only;
}
static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
{
struct commit_list **pp, *parent;
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
struct treesame_state *ts = NULL;
int relevant_change = 0, irrelevant_change = 0;
int relevant_parents, nth_parent;
/*
* If we don't do pruning, everything is interesting
*/
if (!revs->prune)
return;
if (!get_commit_tree(commit))
return;
if (!commit->parents) {
if (rev_same_tree_as_empty(revs, commit))
commit->object.flags |= TREESAME;
return;
}
/*
* Normal non-merge commit? If we don't want to make the
* history dense, we consider it always to be a change..
*/
if (!revs->dense && !commit->parents->next)
return;
for (pp = &commit->parents, nth_parent = 0, relevant_parents = 0;
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
(parent = *pp) != NULL;
pp = &parent->next, nth_parent++) {
struct commit *p = parent->item;
if (relevant_commit(p))
relevant_parents++;
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
if (nth_parent == 1) {
/*
* This our second loop iteration - so we now know
* we're dealing with a merge.
*
* Do not compare with later parents when we care only about
* the first parent chain, in order to avoid derailing the
* traversal to follow a side branch that brought everything
* in the path we are limited to by the pathspec.
*/
if (revs->first_parent_only)
break;
/*
* If this will remain a potentially-simplifiable
* merge, remember per-parent treesame if needed.
* Initialise the array with the comparison from our
* first iteration.
*/
if (revs->treesame.name &&
!revs->simplify_history &&
!(commit->object.flags & UNINTERESTING)) {
ts = initialise_treesame(revs, commit);
if (!(irrelevant_change || relevant_change))
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
ts->treesame[0] = 1;
}
}
if (repo_parse_commit(revs->repo, p) < 0)
die("cannot simplify commit %s (because of %s)",
oid_to_hex(&commit->object.oid),
oid_to_hex(&p->object.oid));
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
switch (rev_compare_tree(revs, p, commit, nth_parent)) {
case REV_TREE_SAME:
if (!revs->simplify_history || !relevant_commit(p)) {
/* Even if a merge with an uninteresting
* side branch brought the entire change
* we are interested in, we do not want
* to lose the other branches of this
* merge, so we just keep going.
*/
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
if (ts)
ts->treesame[nth_parent] = 1;
continue;
}
parent->next = NULL;
commit->parents = parent;
revision: --show-pulls adds helpful merges The default file history simplification of "git log -- <path>" or "git rev-list -- <path>" focuses on providing the smallest set of commits that first contributed a change. The revision walk greatly restricts the set of walked commits by visiting only the first TREESAME parent of a merge commit, when one exists. This means that portions of the commit-graph are not walked, which can be a performance benefit, but can also "hide" commits that added changes but were ignored by a merge resolution. The --full-history option modifies this by walking all commits and reporting a merge commit as "interesting" if it has _any_ parent that is not TREESAME. This tends to be an over-representation of important commits, especially in an environment where most merge commits are created by pull request completion. Suppose we have a commit A and we create a commit B on top that changes our file. When we merge the pull request, we create a merge commit M. If no one else changed the file in the first-parent history between M and A, then M will not be TREESAME to its first parent, but will be TREESAME to B. Thus, the simplified history will be "B". However, M will appear in the --full-history mode. However, suppose that a number of topics T1, T2, ..., Tn were created based on commits C1, C2, ..., Cn between A and M as follows: A----C1----C2--- ... ---Cn----M------P1---P2--- ... ---Pn \ \ \ \ / / / / \ \__.. \ \/ ..__T1 / Tn \ \__.. /\ ..__T2 / \_____________________B \____________________/ If the commits T1, T2, ... Tn did not change the file, then all of P1 through Pn will be TREESAME to their first parent, but not TREESAME to their second. This means that all of those merge commits appear in the --full-history view, with edges that immediately collapse into the lower history without introducing interesting single-parent commits. The --simplify-merges option was introduced to remove these extra merge commits. By noticing that the rewritten parents are reachable from their first parents, those edges can be simplified away. Finally, the commits now look like single-parent commits that are TREESAME to their "only" parent. Thus, they are removed and this issue does not cause issues anymore. However, this also ends up removing the commit M from the history view! Even worse, the --simplify-merges option requires walking the entire history before returning a single result. Many Git users are using Git alongside a Git service that provides code storage alongside a code review tool commonly called "Pull Requests" or "Merge Requests" against a target branch. When these requests are accepted and merged, they typically create a merge commit whose first parent is the previous branch tip and the second parent is the tip of the topic branch used for the request. This presents a valuable order to the parents, but also makes that merge commit slightly special. Users may want to see not only which commits changed a file, but which pull requests merged those commits into their branch. In the previous example, this would mean the users want to see the merge commit "M" in addition to the single- parent commit "C". Users are even more likely to want these merge commits when they use pull requests to merge into a feature branch before merging that feature branch into their trunk. In some sense, users are asking for the "first" merge commit to bring in the change to their branch. As long as the parent order is consistent, this can be handled with the following rule: Include a merge commit if it is not TREESAME to its first parent, but is TREESAME to a later parent. These merges look like the merge commits that would result from running "git pull <topic>" on a main branch. Thus, the option to show these commits is called "--show-pulls". This has the added benefit of showing the commits created by closing a pull request or merge request on any of the Git hosting and code review platforms. To test these options, extend the standard test example to include a merge commit that is not TREESAME to its first parent. It is surprising that that option was not already in the example, as it is instructive. In particular, this extension demonstrates a common issue with file history simplification. When a user resolves a merge conflict using "-Xours" or otherwise ignoring one side of the conflict, they create a TREESAME edge that probably should not be TREESAME. This leads users to become frustrated and complain that "my change disappeared!" In my experience, showing them history with --full-history and --simplify-merges quickly reveals the problematic merge. As mentioned, this option is expensive to compute. The --show-pulls option _might_ show the merge commit (usually titled "resolving conflicts") more quickly. Of course, this depends on the user having the correct parent order, which is backwards when using "git pull master" from a topic branch. There are some special considerations when combining the --show-pulls option with --simplify-merges. This requires adding a new PULL_MERGE object flag to store the information from the initial TREESAME comparisons. This helps avoid dropping those commits in later filters. This is covered by a test, including how the parents can be simplified. Since "struct object" has already ruined its 32-bit alignment by using 33 bits across parsed, type, and flags member, let's not make it worse. PULL_MERGE is used in revision.c with the same value (1u<<15) as REACHABLE in commit-graph.c. The REACHABLE flag is only used when writing a commit-graph file, and a revision walk using --show-pulls does not happen in the same process. Care must be taken in the future to ensure this remains the case. Update Documentation/rev-list-options.txt with significant details around this option. This requires updating the example in the History Simplification section to demonstrate some of the problems with TREESAME second parents. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-10 12:19:43 +00:00
/*
* A merge commit is a "diversion" if it is not
* TREESAME to its first parent but is TREESAME
* to a later parent. In the simplified history,
* we "divert" the history walk to the later
* parent. These commits are shown when "show_pulls"
* is enabled, so do not mark the object as
* TREESAME here.
*/
if (!revs->show_pulls || !nth_parent)
commit->object.flags |= TREESAME;
return;
case REV_TREE_NEW:
if (revs->remove_empty_trees &&
rev_same_tree_as_empty(revs, p)) {
/* We are adding all the specified
* paths from this parent, so the
* history beyond this parent is not
* interesting. Remove its parents
* (they are grandparents for us).
* IOW, we pretend this parent is a
* "root" commit.
*/
if (repo_parse_commit(revs->repo, p) < 0)
die("cannot simplify commit %s (invalid %s)",
oid_to_hex(&commit->object.oid),
oid_to_hex(&p->object.oid));
p->parents = NULL;
}
/* fallthrough */
case REV_TREE_OLD:
case REV_TREE_DIFFERENT:
if (relevant_commit(p))
relevant_change = 1;
else
irrelevant_change = 1;
revision: --show-pulls adds helpful merges The default file history simplification of "git log -- <path>" or "git rev-list -- <path>" focuses on providing the smallest set of commits that first contributed a change. The revision walk greatly restricts the set of walked commits by visiting only the first TREESAME parent of a merge commit, when one exists. This means that portions of the commit-graph are not walked, which can be a performance benefit, but can also "hide" commits that added changes but were ignored by a merge resolution. The --full-history option modifies this by walking all commits and reporting a merge commit as "interesting" if it has _any_ parent that is not TREESAME. This tends to be an over-representation of important commits, especially in an environment where most merge commits are created by pull request completion. Suppose we have a commit A and we create a commit B on top that changes our file. When we merge the pull request, we create a merge commit M. If no one else changed the file in the first-parent history between M and A, then M will not be TREESAME to its first parent, but will be TREESAME to B. Thus, the simplified history will be "B". However, M will appear in the --full-history mode. However, suppose that a number of topics T1, T2, ..., Tn were created based on commits C1, C2, ..., Cn between A and M as follows: A----C1----C2--- ... ---Cn----M------P1---P2--- ... ---Pn \ \ \ \ / / / / \ \__.. \ \/ ..__T1 / Tn \ \__.. /\ ..__T2 / \_____________________B \____________________/ If the commits T1, T2, ... Tn did not change the file, then all of P1 through Pn will be TREESAME to their first parent, but not TREESAME to their second. This means that all of those merge commits appear in the --full-history view, with edges that immediately collapse into the lower history without introducing interesting single-parent commits. The --simplify-merges option was introduced to remove these extra merge commits. By noticing that the rewritten parents are reachable from their first parents, those edges can be simplified away. Finally, the commits now look like single-parent commits that are TREESAME to their "only" parent. Thus, they are removed and this issue does not cause issues anymore. However, this also ends up removing the commit M from the history view! Even worse, the --simplify-merges option requires walking the entire history before returning a single result. Many Git users are using Git alongside a Git service that provides code storage alongside a code review tool commonly called "Pull Requests" or "Merge Requests" against a target branch. When these requests are accepted and merged, they typically create a merge commit whose first parent is the previous branch tip and the second parent is the tip of the topic branch used for the request. This presents a valuable order to the parents, but also makes that merge commit slightly special. Users may want to see not only which commits changed a file, but which pull requests merged those commits into their branch. In the previous example, this would mean the users want to see the merge commit "M" in addition to the single- parent commit "C". Users are even more likely to want these merge commits when they use pull requests to merge into a feature branch before merging that feature branch into their trunk. In some sense, users are asking for the "first" merge commit to bring in the change to their branch. As long as the parent order is consistent, this can be handled with the following rule: Include a merge commit if it is not TREESAME to its first parent, but is TREESAME to a later parent. These merges look like the merge commits that would result from running "git pull <topic>" on a main branch. Thus, the option to show these commits is called "--show-pulls". This has the added benefit of showing the commits created by closing a pull request or merge request on any of the Git hosting and code review platforms. To test these options, extend the standard test example to include a merge commit that is not TREESAME to its first parent. It is surprising that that option was not already in the example, as it is instructive. In particular, this extension demonstrates a common issue with file history simplification. When a user resolves a merge conflict using "-Xours" or otherwise ignoring one side of the conflict, they create a TREESAME edge that probably should not be TREESAME. This leads users to become frustrated and complain that "my change disappeared!" In my experience, showing them history with --full-history and --simplify-merges quickly reveals the problematic merge. As mentioned, this option is expensive to compute. The --show-pulls option _might_ show the merge commit (usually titled "resolving conflicts") more quickly. Of course, this depends on the user having the correct parent order, which is backwards when using "git pull master" from a topic branch. There are some special considerations when combining the --show-pulls option with --simplify-merges. This requires adding a new PULL_MERGE object flag to store the information from the initial TREESAME comparisons. This helps avoid dropping those commits in later filters. This is covered by a test, including how the parents can be simplified. Since "struct object" has already ruined its 32-bit alignment by using 33 bits across parsed, type, and flags member, let's not make it worse. PULL_MERGE is used in revision.c with the same value (1u<<15) as REACHABLE in commit-graph.c. The REACHABLE flag is only used when writing a commit-graph file, and a revision walk using --show-pulls does not happen in the same process. Care must be taken in the future to ensure this remains the case. Update Documentation/rev-list-options.txt with significant details around this option. This requires updating the example in the History Simplification section to demonstrate some of the problems with TREESAME second parents. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-10 12:19:43 +00:00
if (!nth_parent)
commit->object.flags |= PULL_MERGE;
continue;
}
die("bad tree compare for commit %s", oid_to_hex(&commit->object.oid));
}
/*
* TREESAME is straightforward for single-parent commits. For merge
* commits, it is most useful to define it so that "irrelevant"
* parents cannot make us !TREESAME - if we have any relevant
* parents, then we only consider TREESAMEness with respect to them,
* allowing irrelevant merges from uninteresting branches to be
* simplified away. Only if we have only irrelevant parents do we
* base TREESAME on them. Note that this logic is replicated in
* update_treesame, which should be kept in sync.
*/
if (relevant_parents ? !relevant_change : !irrelevant_change)
commit->object.flags |= TREESAME;
}
static int process_parents(struct rev_info *revs, struct commit *commit,
revision: use a prio_queue to hold rewritten parents This patch fixes a quadratic list insertion in rewrite_one() when pathspec limiting is combined with --parents. What happens is something like this: 1. We see that some commit X touches the path, so we try to rewrite its parents. 2. rewrite_one() loops forever, rewriting parents, until it finds a relevant parent (or hits the root and decides there are none). The heavy lifting is done by process_parent(), which uses try_to_simplify_commit() to drop parents. 3. process_parent() puts any intermediate parents into the &revs->commits list, inserting by commit date as usual. So if commit X is recent, and then there's a large chunk of history that doesn't touch the path, we may add a lot of commits to &revs->commits. And insertion by commit date is O(n) in the worst case, making the whole thing quadratic. We tried to deal with this long ago in fce87ae538 (Fix quadratic performance in rewrite_one., 2008-07-12). In that scheme, we cache the oldest commit in the list; if the new commit to be added is older, we can start our linear traversal there. This often works well in practice because parents are older than their descendants, and thus we tend to add older and older commits as we traverse. But this isn't guaranteed, and in fact there's a simple case where it is not: merges. Imagine we look at the first parent of a merge and see a very old commit (let's say 3 years old). And on the second parent, as we go back 3 years in history, we might have many commits. That one first-parent commit has polluted our oldest-commit cache; it will remain the oldest while we traverse a huge chunk of history, during which we have to fall back to the slow, linear method of adding to the list. Naively, one might imagine that instead of caching the oldest commit, we'd start at the last-added one. But that just makes some cases faster while making others slower (and indeed, while it made a real-world test case much faster, it does quite poorly in the perf test include here). Fundamentally, these are just heuristics; our worst case is still quadratic, and some cases will approach that. Instead, let's use a data structure with better worst-case performance. Swapping out revs->commits for something else would have repercussions all over the code base, but we can take advantage of one fact: for the rewrite_one() case, nobody actually needs to see those commits in revs->commits until we've finished generating the whole list. That leaves us with two obvious options: 1. We can generate the list _unordered_, which should be O(n), and then sort it afterwards, which would be O(n log n) total. This is "sort-after" below. 2. We can insert the commits into a separate data structure, like a priority queue. This is "prio-queue" below. I expected that sort-after would be the fastest (since it saves us the extra step of copying the items into the linked list), but surprisingly the prio-queue seems to be a bit faster. Here are timings for the new p0001.6 for all three techniques across a few repositories, as compared to master: master cache-last sort-after prio-queue -------------------------------------------------------------------------------------------- GIT_PERF_REPO=git.git 0.52(0.50+0.02) 0.53(0.51+0.02) +1.9% 0.37(0.33+0.03) -28.8% 0.37(0.32+0.04) -28.8% GIT_PERF_REPO=linux.git 20.81(20.74+0.07) 20.31(20.24+0.07) -2.4% 0.94(0.86+0.07) -95.5% 0.91(0.82+0.09) -95.6% GIT_PERF_REPO=llvm-project.git 83.67(83.57+0.09) 4.23(4.15+0.08) -94.9% 3.21(3.15+0.06) -96.2% 2.98(2.91+0.07) -96.4% A few items to note: - the cache-list tweak does improve the bad case for llvm-project.git that started my digging into this problem. But it performs terribly on linux.git, barely helping at all. - the sort-after and prio-queue techniques work well. They approach the timing for running without --parents at all, which is what you'd expect (see below for more data). - prio-queue just barely outperforms sort-after. As I said, I'm not really sure why this is the case, but it is. You can see it even more prominently in this real-world case on llvm-project.git: git rev-list --parents 07ef786652e7 -- llvm/test/CodeGen/Generic/bswap.ll where prio-queue routinely outperforms sort-after by about 7%. One guess is that the prio-queue may just be more efficient because it uses a compact array. There are three new perf tests: - "rev-list --parents" gives us a baseline for running with --parents. This isn't sped up meaningfully here, because the bad case is triggered only with simplification. But it's good to make sure we don't screw it up (now, or in the future). - "rev-list -- dummy" gives us a baseline for just traversing with pathspec limiting. This gives a lower bound for the next test (and it's also a good thing for us to be checking in general for regressions, since we don't seem to have any existing tests). - "rev-list --parents -- dummy" shows off the problem (and our fix) Here are the timings for those three on llvm-project.git, before and after the fix: Test master prio-queue ------------------------------------------------------------------------------ 0001.3: rev-list --parents 2.24(2.12+0.12) 2.22(2.11+0.11) -0.9% 0001.5: rev-list -- dummy 2.89(2.82+0.07) 2.92(2.89+0.03) +1.0% 0001.6: rev-list --parents -- dummy 83.67(83.57+0.09) 2.98(2.91+0.07) -96.4% Changes in the first two are basically noise, and you can see we approach our lower bound in the final one. Note that we can't fully get rid of the list argument from process_parents(). Other callers do have lists, and it would be hard to convert them. They also don't seem to have this problem (probably because they actually remove items from the list as they loop, meaning it doesn't grow so large in the first place). So this basically just drops the "cache_ptr" parameter (which was used only by the one caller we're fixing here) and replaces it with a prio_queue. Callers are free to use either data structure, depending on what they're prepared to handle. Reported-by: Björn Pettersson A <bjorn.a.pettersson@ericsson.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-04 01:41:09 +00:00
struct commit_list **list, struct prio_queue *queue)
{
struct commit_list *parent = commit->parents;
unsigned left_flag;
if (commit->object.flags & ADDED)
return 0;
commit->object.flags |= ADDED;
if (revs->include_check &&
!revs->include_check(commit, revs->include_check_data))
return 0;
/*
* If the commit is uninteresting, don't try to
* prune parents - we want the maximal uninteresting
* set.
*
* Normally we haven't parsed the parent
* yet, so we won't have a parent of a parent
* here. However, it may turn out that we've
* reached this commit some other way (where it
* wasn't uninteresting), in which case we need
* to mark its parents recursively too..
*/
if (commit->object.flags & UNINTERESTING) {
while (parent) {
struct commit *p = parent->item;
parent = parent->next;
if (p)
p->object.flags |= UNINTERESTING;
if (repo_parse_commit_gently(revs->repo, p, 1) < 0)
continue;
if (p->parents)
mark_parents_uninteresting(revs, p);
if (p->object.flags & SEEN)
continue;
p->object.flags |= (SEEN | NOT_USER_GIVEN);
if (list)
revision: use a prio_queue to hold rewritten parents This patch fixes a quadratic list insertion in rewrite_one() when pathspec limiting is combined with --parents. What happens is something like this: 1. We see that some commit X touches the path, so we try to rewrite its parents. 2. rewrite_one() loops forever, rewriting parents, until it finds a relevant parent (or hits the root and decides there are none). The heavy lifting is done by process_parent(), which uses try_to_simplify_commit() to drop parents. 3. process_parent() puts any intermediate parents into the &revs->commits list, inserting by commit date as usual. So if commit X is recent, and then there's a large chunk of history that doesn't touch the path, we may add a lot of commits to &revs->commits. And insertion by commit date is O(n) in the worst case, making the whole thing quadratic. We tried to deal with this long ago in fce87ae538 (Fix quadratic performance in rewrite_one., 2008-07-12). In that scheme, we cache the oldest commit in the list; if the new commit to be added is older, we can start our linear traversal there. This often works well in practice because parents are older than their descendants, and thus we tend to add older and older commits as we traverse. But this isn't guaranteed, and in fact there's a simple case where it is not: merges. Imagine we look at the first parent of a merge and see a very old commit (let's say 3 years old). And on the second parent, as we go back 3 years in history, we might have many commits. That one first-parent commit has polluted our oldest-commit cache; it will remain the oldest while we traverse a huge chunk of history, during which we have to fall back to the slow, linear method of adding to the list. Naively, one might imagine that instead of caching the oldest commit, we'd start at the last-added one. But that just makes some cases faster while making others slower (and indeed, while it made a real-world test case much faster, it does quite poorly in the perf test include here). Fundamentally, these are just heuristics; our worst case is still quadratic, and some cases will approach that. Instead, let's use a data structure with better worst-case performance. Swapping out revs->commits for something else would have repercussions all over the code base, but we can take advantage of one fact: for the rewrite_one() case, nobody actually needs to see those commits in revs->commits until we've finished generating the whole list. That leaves us with two obvious options: 1. We can generate the list _unordered_, which should be O(n), and then sort it afterwards, which would be O(n log n) total. This is "sort-after" below. 2. We can insert the commits into a separate data structure, like a priority queue. This is "prio-queue" below. I expected that sort-after would be the fastest (since it saves us the extra step of copying the items into the linked list), but surprisingly the prio-queue seems to be a bit faster. Here are timings for the new p0001.6 for all three techniques across a few repositories, as compared to master: master cache-last sort-after prio-queue -------------------------------------------------------------------------------------------- GIT_PERF_REPO=git.git 0.52(0.50+0.02) 0.53(0.51+0.02) +1.9% 0.37(0.33+0.03) -28.8% 0.37(0.32+0.04) -28.8% GIT_PERF_REPO=linux.git 20.81(20.74+0.07) 20.31(20.24+0.07) -2.4% 0.94(0.86+0.07) -95.5% 0.91(0.82+0.09) -95.6% GIT_PERF_REPO=llvm-project.git 83.67(83.57+0.09) 4.23(4.15+0.08) -94.9% 3.21(3.15+0.06) -96.2% 2.98(2.91+0.07) -96.4% A few items to note: - the cache-list tweak does improve the bad case for llvm-project.git that started my digging into this problem. But it performs terribly on linux.git, barely helping at all. - the sort-after and prio-queue techniques work well. They approach the timing for running without --parents at all, which is what you'd expect (see below for more data). - prio-queue just barely outperforms sort-after. As I said, I'm not really sure why this is the case, but it is. You can see it even more prominently in this real-world case on llvm-project.git: git rev-list --parents 07ef786652e7 -- llvm/test/CodeGen/Generic/bswap.ll where prio-queue routinely outperforms sort-after by about 7%. One guess is that the prio-queue may just be more efficient because it uses a compact array. There are three new perf tests: - "rev-list --parents" gives us a baseline for running with --parents. This isn't sped up meaningfully here, because the bad case is triggered only with simplification. But it's good to make sure we don't screw it up (now, or in the future). - "rev-list -- dummy" gives us a baseline for just traversing with pathspec limiting. This gives a lower bound for the next test (and it's also a good thing for us to be checking in general for regressions, since we don't seem to have any existing tests). - "rev-list --parents -- dummy" shows off the problem (and our fix) Here are the timings for those three on llvm-project.git, before and after the fix: Test master prio-queue ------------------------------------------------------------------------------ 0001.3: rev-list --parents 2.24(2.12+0.12) 2.22(2.11+0.11) -0.9% 0001.5: rev-list -- dummy 2.89(2.82+0.07) 2.92(2.89+0.03) +1.0% 0001.6: rev-list --parents -- dummy 83.67(83.57+0.09) 2.98(2.91+0.07) -96.4% Changes in the first two are basically noise, and you can see we approach our lower bound in the final one. Note that we can't fully get rid of the list argument from process_parents(). Other callers do have lists, and it would be hard to convert them. They also don't seem to have this problem (probably because they actually remove items from the list as they loop, meaning it doesn't grow so large in the first place). So this basically just drops the "cache_ptr" parameter (which was used only by the one caller we're fixing here) and replaces it with a prio_queue. Callers are free to use either data structure, depending on what they're prepared to handle. Reported-by: Björn Pettersson A <bjorn.a.pettersson@ericsson.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-04 01:41:09 +00:00
commit_list_insert_by_date(p, list);
if (queue)
prio_queue_put(queue, p);
if (revs->exclude_first_parent_only)
break;
}
return 0;
}
/*
* Ok, the commit wasn't uninteresting. Try to
* simplify the commit history and find the parent
* that has no differences in the path set if one exists.
*/
try_to_simplify_commit(revs, commit);
if (revs->no_walk)
return 0;
left_flag = (commit->object.flags & SYMMETRIC_LEFT);
for (parent = commit->parents; parent; parent = parent->next) {
struct commit *p = parent->item;
int gently = revs->ignore_missing_links ||
revs->exclude_promisor_objects;
if (repo_parse_commit_gently(revs->repo, p, gently) < 0) {
if (revs->exclude_promisor_objects &&
is_promisor_object(&p->object.oid)) {
if (revs->first_parent_only)
break;
continue;
}
return -1;
}
if (revs->sources) {
char **slot = revision_sources_at(revs->sources, p);
if (!*slot)
*slot = *revision_sources_at(revs->sources, commit);
}
p->object.flags |= left_flag;
if (!(p->object.flags & SEEN)) {
p->object.flags |= (SEEN | NOT_USER_GIVEN);
if (list)
revision: use a prio_queue to hold rewritten parents This patch fixes a quadratic list insertion in rewrite_one() when pathspec limiting is combined with --parents. What happens is something like this: 1. We see that some commit X touches the path, so we try to rewrite its parents. 2. rewrite_one() loops forever, rewriting parents, until it finds a relevant parent (or hits the root and decides there are none). The heavy lifting is done by process_parent(), which uses try_to_simplify_commit() to drop parents. 3. process_parent() puts any intermediate parents into the &revs->commits list, inserting by commit date as usual. So if commit X is recent, and then there's a large chunk of history that doesn't touch the path, we may add a lot of commits to &revs->commits. And insertion by commit date is O(n) in the worst case, making the whole thing quadratic. We tried to deal with this long ago in fce87ae538 (Fix quadratic performance in rewrite_one., 2008-07-12). In that scheme, we cache the oldest commit in the list; if the new commit to be added is older, we can start our linear traversal there. This often works well in practice because parents are older than their descendants, and thus we tend to add older and older commits as we traverse. But this isn't guaranteed, and in fact there's a simple case where it is not: merges. Imagine we look at the first parent of a merge and see a very old commit (let's say 3 years old). And on the second parent, as we go back 3 years in history, we might have many commits. That one first-parent commit has polluted our oldest-commit cache; it will remain the oldest while we traverse a huge chunk of history, during which we have to fall back to the slow, linear method of adding to the list. Naively, one might imagine that instead of caching the oldest commit, we'd start at the last-added one. But that just makes some cases faster while making others slower (and indeed, while it made a real-world test case much faster, it does quite poorly in the perf test include here). Fundamentally, these are just heuristics; our worst case is still quadratic, and some cases will approach that. Instead, let's use a data structure with better worst-case performance. Swapping out revs->commits for something else would have repercussions all over the code base, but we can take advantage of one fact: for the rewrite_one() case, nobody actually needs to see those commits in revs->commits until we've finished generating the whole list. That leaves us with two obvious options: 1. We can generate the list _unordered_, which should be O(n), and then sort it afterwards, which would be O(n log n) total. This is "sort-after" below. 2. We can insert the commits into a separate data structure, like a priority queue. This is "prio-queue" below. I expected that sort-after would be the fastest (since it saves us the extra step of copying the items into the linked list), but surprisingly the prio-queue seems to be a bit faster. Here are timings for the new p0001.6 for all three techniques across a few repositories, as compared to master: master cache-last sort-after prio-queue -------------------------------------------------------------------------------------------- GIT_PERF_REPO=git.git 0.52(0.50+0.02) 0.53(0.51+0.02) +1.9% 0.37(0.33+0.03) -28.8% 0.37(0.32+0.04) -28.8% GIT_PERF_REPO=linux.git 20.81(20.74+0.07) 20.31(20.24+0.07) -2.4% 0.94(0.86+0.07) -95.5% 0.91(0.82+0.09) -95.6% GIT_PERF_REPO=llvm-project.git 83.67(83.57+0.09) 4.23(4.15+0.08) -94.9% 3.21(3.15+0.06) -96.2% 2.98(2.91+0.07) -96.4% A few items to note: - the cache-list tweak does improve the bad case for llvm-project.git that started my digging into this problem. But it performs terribly on linux.git, barely helping at all. - the sort-after and prio-queue techniques work well. They approach the timing for running without --parents at all, which is what you'd expect (see below for more data). - prio-queue just barely outperforms sort-after. As I said, I'm not really sure why this is the case, but it is. You can see it even more prominently in this real-world case on llvm-project.git: git rev-list --parents 07ef786652e7 -- llvm/test/CodeGen/Generic/bswap.ll where prio-queue routinely outperforms sort-after by about 7%. One guess is that the prio-queue may just be more efficient because it uses a compact array. There are three new perf tests: - "rev-list --parents" gives us a baseline for running with --parents. This isn't sped up meaningfully here, because the bad case is triggered only with simplification. But it's good to make sure we don't screw it up (now, or in the future). - "rev-list -- dummy" gives us a baseline for just traversing with pathspec limiting. This gives a lower bound for the next test (and it's also a good thing for us to be checking in general for regressions, since we don't seem to have any existing tests). - "rev-list --parents -- dummy" shows off the problem (and our fix) Here are the timings for those three on llvm-project.git, before and after the fix: Test master prio-queue ------------------------------------------------------------------------------ 0001.3: rev-list --parents 2.24(2.12+0.12) 2.22(2.11+0.11) -0.9% 0001.5: rev-list -- dummy 2.89(2.82+0.07) 2.92(2.89+0.03) +1.0% 0001.6: rev-list --parents -- dummy 83.67(83.57+0.09) 2.98(2.91+0.07) -96.4% Changes in the first two are basically noise, and you can see we approach our lower bound in the final one. Note that we can't fully get rid of the list argument from process_parents(). Other callers do have lists, and it would be hard to convert them. They also don't seem to have this problem (probably because they actually remove items from the list as they loop, meaning it doesn't grow so large in the first place). So this basically just drops the "cache_ptr" parameter (which was used only by the one caller we're fixing here) and replaces it with a prio_queue. Callers are free to use either data structure, depending on what they're prepared to handle. Reported-by: Björn Pettersson A <bjorn.a.pettersson@ericsson.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-04 01:41:09 +00:00
commit_list_insert_by_date(p, list);
if (queue)
prio_queue_put(queue, p);
}
if (revs->first_parent_only)
break;
}
return 0;
}
static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
{
struct commit_list *p;
int left_count = 0, right_count = 0;
int left_first;
struct patch_ids ids;
unsigned cherry_flag;
/* First count the commits on the left and on the right */
for (p = list; p; p = p->next) {
struct commit *commit = p->item;
unsigned flags = commit->object.flags;
if (flags & BOUNDARY)
;
else if (flags & SYMMETRIC_LEFT)
left_count++;
else
right_count++;
}
if (!left_count || !right_count)
return;
left_first = left_count < right_count;
init_patch_ids(revs->repo, &ids);
ids.diffopts.pathspec = revs->diffopt.pathspec;
/* Compute patch-ids for one side */
for (p = list; p; p = p->next) {
struct commit *commit = p->item;
unsigned flags = commit->object.flags;
if (flags & BOUNDARY)
continue;
/*
* If we have fewer left, left_first is set and we omit
* commits on the right branch in this loop. If we have
* fewer right, we skip the left ones.
*/
if (left_first != !!(flags & SYMMETRIC_LEFT))
continue;
add_commit_patch_id(commit, &ids);
}
/* either cherry_mark or cherry_pick are true */
cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;
/* Check the other side */
for (p = list; p; p = p->next) {
struct commit *commit = p->item;
struct patch_id *id;
unsigned flags = commit->object.flags;
if (flags & BOUNDARY)
continue;
/*
* If we have fewer left, left_first is set and we omit
* commits on the left branch in this loop.
*/
if (left_first == !!(flags & SYMMETRIC_LEFT))
continue;
/*
* Have we seen the same patch id?
*/
patch-ids: handle duplicate hashmap entries This fixes a bug introduced in dfb7a1b4d0 (patch-ids: stop using a hand-rolled hashmap implementation, 2016-07-29) in which git rev-list --cherry-pick A...B will fail to suppress commits reachable from A even if a commit with matching patch-id appears in B. Around the time of that commit, the algorithm for "--cherry-pick" looked something like this: 0. Traverse all of the commits, marking them as being on the left or right side of the symmetric difference. 1. Iterate over the left-hand commits, inserting a patch-id struct for each into a hashmap, and pointing commit->util to the patch-id struct. 2. Iterate over the right-hand commits, checking which are present in the hashmap. If so, we exclude the commit from the output _and_ we mark the patch-id as "seen". 3. Iterate again over the left-hand commits, checking whether commit->util->seen is set; if so, exclude them from the output. At the end, we'll have eliminated commits from both sides that have a matching patch-id on the other side. But there's a subtle assumption here: for any given patch-id, we must have exactly one struct representing it. If two commits from A both have the same patch-id and we allow duplicates in the hashmap, then we run into a problem: a. In step 1, we insert two patch-id structs into the hashmap. b. In step 2, our lookups will find only one of these structs, so only one "seen" flag is marked. c. In step 3, one of the commits in A will have its commit->util->seen set, but the other will not. We'll erroneously output the latter. Prior to dfb7a1b4d0, our hashmap did not allow duplicates. Afterwards, it used hashmap_add(), which explicitly does allow duplicates. At that point, the solution would have been easy: when we are about to add a duplicate, skip doing so and return the existing entry which matches. But it gets more complicated. In 683f17ec44 (patch-ids: replace the seen indicator with a commit pointer, 2016-07-29), our step 3 goes away entirely. Instead, in step 2, when the right-hand side finds a matching patch_id from the left-hand side, we can directly mark the left-hand patch_id->commit to be omitted. Solving that would be easy, too; there's a one-to-many relationship of patch-ids to commits, so we just need to keep a list. But there's more. Commit b3dfeebb92 (rebase: avoid computing unnecessary patch IDs, 2016-07-29) built on that by lazily computing the full patch-ids. So we don't even know when adding to the hashmap whether two commits truly have the same id. We'd have to tentatively assign them a list, and then possibly split them apart (possibly into N new structs) at the moment we compute the real patch-ids. This could work, but it's complicated and error-prone. Instead, let's accept that we may store duplicates, and teach the lookup side to be more clever. Rather than asking for a single matching patch-id, it will need to iterate over all matching patch-ids. This does mean examining every entry in a single hash bucket, but the worst-case for a hash lookup was already doing that. We'll keep the hashmap details out of the caller by providing a simple iteration interface. We can retain the simple has_commit_patch_id() interface for the other callers, but we'll simplify its return value into an integer, rather than returning the patch_id struct. That way they won't be tempted to look at the "commit" field of the return value without iterating. Reported-by: Arnaud Morin <arnaud.morin@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12 15:52:32 +00:00
id = patch_id_iter_first(commit, &ids);
if (!id)
continue;
commit->object.flags |= cherry_flag;
patch-ids: handle duplicate hashmap entries This fixes a bug introduced in dfb7a1b4d0 (patch-ids: stop using a hand-rolled hashmap implementation, 2016-07-29) in which git rev-list --cherry-pick A...B will fail to suppress commits reachable from A even if a commit with matching patch-id appears in B. Around the time of that commit, the algorithm for "--cherry-pick" looked something like this: 0. Traverse all of the commits, marking them as being on the left or right side of the symmetric difference. 1. Iterate over the left-hand commits, inserting a patch-id struct for each into a hashmap, and pointing commit->util to the patch-id struct. 2. Iterate over the right-hand commits, checking which are present in the hashmap. If so, we exclude the commit from the output _and_ we mark the patch-id as "seen". 3. Iterate again over the left-hand commits, checking whether commit->util->seen is set; if so, exclude them from the output. At the end, we'll have eliminated commits from both sides that have a matching patch-id on the other side. But there's a subtle assumption here: for any given patch-id, we must have exactly one struct representing it. If two commits from A both have the same patch-id and we allow duplicates in the hashmap, then we run into a problem: a. In step 1, we insert two patch-id structs into the hashmap. b. In step 2, our lookups will find only one of these structs, so only one "seen" flag is marked. c. In step 3, one of the commits in A will have its commit->util->seen set, but the other will not. We'll erroneously output the latter. Prior to dfb7a1b4d0, our hashmap did not allow duplicates. Afterwards, it used hashmap_add(), which explicitly does allow duplicates. At that point, the solution would have been easy: when we are about to add a duplicate, skip doing so and return the existing entry which matches. But it gets more complicated. In 683f17ec44 (patch-ids: replace the seen indicator with a commit pointer, 2016-07-29), our step 3 goes away entirely. Instead, in step 2, when the right-hand side finds a matching patch_id from the left-hand side, we can directly mark the left-hand patch_id->commit to be omitted. Solving that would be easy, too; there's a one-to-many relationship of patch-ids to commits, so we just need to keep a list. But there's more. Commit b3dfeebb92 (rebase: avoid computing unnecessary patch IDs, 2016-07-29) built on that by lazily computing the full patch-ids. So we don't even know when adding to the hashmap whether two commits truly have the same id. We'd have to tentatively assign them a list, and then possibly split them apart (possibly into N new structs) at the moment we compute the real patch-ids. This could work, but it's complicated and error-prone. Instead, let's accept that we may store duplicates, and teach the lookup side to be more clever. Rather than asking for a single matching patch-id, it will need to iterate over all matching patch-ids. This does mean examining every entry in a single hash bucket, but the worst-case for a hash lookup was already doing that. We'll keep the hashmap details out of the caller by providing a simple iteration interface. We can retain the simple has_commit_patch_id() interface for the other callers, but we'll simplify its return value into an integer, rather than returning the patch_id struct. That way they won't be tempted to look at the "commit" field of the return value without iterating. Reported-by: Arnaud Morin <arnaud.morin@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12 15:52:32 +00:00
do {
id->commit->object.flags |= cherry_flag;
} while ((id = patch_id_iter_next(id, &ids)));
}
free_patch_ids(&ids);
}
/* How many extra uninteresting commits we want to see.. */
#define SLOP 5
static int still_interesting(struct commit_list *src, timestamp_t date, int slop,
limit_list: avoid quadratic behavior from still_interesting When we are limiting a rev-list traversal due to UNINTERESTING refs, we have to walk down the tips (both interesting and uninteresting) to find where they intersect. We keep a queue of commits to examine, pop commits off the queue one by one, and potentially add their parents. The size of the queue will naturally fluctuate based on the "width" of the history graph; i.e., the number of simultaneous lines of development. But for the most part it will stay in the same ballpark as the initial number of tips we fed, shrinking over time (as we hit common ancestors of the tips). So roughly speaking, if we start with `N` tips, we'll spend much of the time with a queue around `N` items. For each UNINTERESTING commit we pop, we call still_interesting to check whether marking its parents as UNINTERESTING has made the whole queue uninteresting (in which case we can quit early). Because the queue is stored as a linked list, this is `O(N)`, where `N` is the number of items in the queue. So processing a queue with `N` commits marked UNINTERESTING (and one or more interesting commits) will take `O(N^2)`. If you feed a lot of positive tips, this isn't a problem. They aren't UNINTERESTING, so they don't incur the still_interesting check. It also isn't a problem if you traverse from an interesting tip to some UNINTERESTING bases. We order the queue by recency, so the interesting commits stay at the front of the queue as we walk down them. The linear check can exit early as soon as it sees one interesting commit left in the queue. But if you want to know whether an older commit is reachable from a set of newer tips, we end up processing in the opposite direction: from the UNINTERESTING ones down to the interesting one. This may happen when we call: git rev-list $commits --not --all in check_everything_connected after a fetch. If we fetched something much older than most of our refs, and if we have a large number of refs, the traversal cost is dominated by the quadratic behavior. These commands simulate the connectivity check of such a fetch, when you have `$n` distinct refs in the receiver: # positive ref is 100,000 commits deep git rev-list --all | head -100000 | tail -1 >input # huge number of more recent negative refs git rev-list --all | head -$n | sed s/^/^/ >>input time git rev-list --stdin <input Here are timings for various `n` on the linux.git repository. The `n=1` case provides a baseline for just walking the commits, which lets us see the still_interesting overhead. The times marked with `+` subtract that baseline to show just the extra time growth due to the large number of refs. The `x` numbers show the slowdown of the adjusted time versus the prior trial. n | before | after -------------------------------------------------------- 1 | 0.991s | 0.848s 10000 | 1.120s (+0.129s) | 0.885s (+0.037s) 20000 | 1.451s (+0.460s, 3.5x) | 0.923s (+0.075s, 2.0x) 40000 | 2.731s (+1.740s, 3.8x) | 0.994s (+0.146s, 1.9x) 80000 | 8.235s (+7.244s, 4.2x) | 1.123s (+0.275s, 1.9x) Each trial doubles `n`, so you can see the quadratic (`4x`) behavior before this patch. Afterwards, we have a roughly linear relationship. The implementation is fairly straightforward. Whenever we do the linear search, we cache the interesting commit we find, and next time check it before doing another linear search. If that commit is removed from the list or becomes UNINTERESTING itself, then we fall back to the linear search. This is very similar to the trick used by fce87ae (Fix quadratic performance in rewrite_one., 2008-07-12). I considered and rejected several possible alternatives: 1. Keep a count of UNINTERESTING commits in the queue. This requires managing the count not only when removing an item from the queue, but also when marking an item as UNINTERESTING. That requires touching the other functions which mark commits, and would require knowing quickly which commits are in the queue (lookup in the queue is linear, so we would need an auxiliary structure or to also maintain an IN_QUEUE flag in each commit object). 2. Keep a separate list of interesting commits. Drop items from it when they are dropped from the queue, or if they become UNINTERESTING. This again suffers from extra complexity to maintain the list, not to mention CPU and memory. 3. Use a better data structure for the queue. This is something that could help the fix in fce87ae, because we order the queue by recency, and it is about inserting quickly in recency order. So a normal priority queue would help there. But here, we cannot disturb the order of the queue, which makes things harder. We really do need an auxiliary index to track the flag we care about, which is basically option (2) above. The "cache" trick is simple, and the numbers above show that it works well in practice. This is because the length of time it takes to find an interesting commit is proportional to the length of time it will remain cached (i.e., if we have to walk a long way to find it, it also means we have to pop a lot of elements in the queue until we get rid of it and have to find another interesting commit). The worst case is still quadratic, though. We could have `N` uninteresting commits at the front of the queue, followed by `N` interesting commits, where commit `i` has parent `i+N`. When we pop commit `i`, we will notice that the parent of the next commit, `i+1+N` is still interesting and cache it. But then handling commit `i+1`, we will mark its parent `i+1+N` uninteresting, and immediately invalidate our cache. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-17 22:11:04 +00:00
struct commit **interesting_cache)
Add "--show-all" revision walker flag for debugging It's really not very easy to visualize the commit walker, because - on purpose - it obvously doesn't show the uninteresting commits! This adds a "--show-all" flag to the revision walker, which will make it show uninteresting commits too, and they'll have a '^' in front of them (it also fixes a logic error for !verbose_header for boundary commits - we should show the '-' even if left_right isn't shown). A separate patch to gitk to teach it the new '^' was sent to paulus. With the change in place, it actually is interesting even for the cases that git doesn't have any problems with, ie for the kernel you can do: gitk -d --show-all v2.6.24.. and you see just how far down it has to parse things to see it all. The use of "-d" is a good idea, since the date-ordered toposort is much better at showing why it goes deep down (ie the date of some of those commits after 2.6.24 is much older, because they were merged from trees that weren't rebased). So I think this is a useful feature even for non-debugging - just to visualize what git does internally more. When it actually breaks out due to the "everybody_uninteresting()" case, it adds the uninteresting commits (both the one it's looking at now, and the list of pending ones) to the list This way, we really list *all* the commits we've looked at. Because we now end up listing commits we may not even have been parsed at all "show_log" and "show_commit" need to protect against commits that don't have a commit buffer entry. That second part is debatable just how it should work. Maybe we shouldn't show such entries at all (with this patch those entries do get shown, they just don't get any message shown with them). But I think this is a useful case. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-09 22:02:07 +00:00
{
/*
* No source list at all? We're definitely done..
*/
if (!src)
return 0;
/*
* Does the destination list contain entries with a date
* before the source list? Definitely _not_ done.
*/
if (date <= src->item->date)
return SLOP;
/*
* Does the source list still have interesting commits in
* it? Definitely not done..
*/
limit_list: avoid quadratic behavior from still_interesting When we are limiting a rev-list traversal due to UNINTERESTING refs, we have to walk down the tips (both interesting and uninteresting) to find where they intersect. We keep a queue of commits to examine, pop commits off the queue one by one, and potentially add their parents. The size of the queue will naturally fluctuate based on the "width" of the history graph; i.e., the number of simultaneous lines of development. But for the most part it will stay in the same ballpark as the initial number of tips we fed, shrinking over time (as we hit common ancestors of the tips). So roughly speaking, if we start with `N` tips, we'll spend much of the time with a queue around `N` items. For each UNINTERESTING commit we pop, we call still_interesting to check whether marking its parents as UNINTERESTING has made the whole queue uninteresting (in which case we can quit early). Because the queue is stored as a linked list, this is `O(N)`, where `N` is the number of items in the queue. So processing a queue with `N` commits marked UNINTERESTING (and one or more interesting commits) will take `O(N^2)`. If you feed a lot of positive tips, this isn't a problem. They aren't UNINTERESTING, so they don't incur the still_interesting check. It also isn't a problem if you traverse from an interesting tip to some UNINTERESTING bases. We order the queue by recency, so the interesting commits stay at the front of the queue as we walk down them. The linear check can exit early as soon as it sees one interesting commit left in the queue. But if you want to know whether an older commit is reachable from a set of newer tips, we end up processing in the opposite direction: from the UNINTERESTING ones down to the interesting one. This may happen when we call: git rev-list $commits --not --all in check_everything_connected after a fetch. If we fetched something much older than most of our refs, and if we have a large number of refs, the traversal cost is dominated by the quadratic behavior. These commands simulate the connectivity check of such a fetch, when you have `$n` distinct refs in the receiver: # positive ref is 100,000 commits deep git rev-list --all | head -100000 | tail -1 >input # huge number of more recent negative refs git rev-list --all | head -$n | sed s/^/^/ >>input time git rev-list --stdin <input Here are timings for various `n` on the linux.git repository. The `n=1` case provides a baseline for just walking the commits, which lets us see the still_interesting overhead. The times marked with `+` subtract that baseline to show just the extra time growth due to the large number of refs. The `x` numbers show the slowdown of the adjusted time versus the prior trial. n | before | after -------------------------------------------------------- 1 | 0.991s | 0.848s 10000 | 1.120s (+0.129s) | 0.885s (+0.037s) 20000 | 1.451s (+0.460s, 3.5x) | 0.923s (+0.075s, 2.0x) 40000 | 2.731s (+1.740s, 3.8x) | 0.994s (+0.146s, 1.9x) 80000 | 8.235s (+7.244s, 4.2x) | 1.123s (+0.275s, 1.9x) Each trial doubles `n`, so you can see the quadratic (`4x`) behavior before this patch. Afterwards, we have a roughly linear relationship. The implementation is fairly straightforward. Whenever we do the linear search, we cache the interesting commit we find, and next time check it before doing another linear search. If that commit is removed from the list or becomes UNINTERESTING itself, then we fall back to the linear search. This is very similar to the trick used by fce87ae (Fix quadratic performance in rewrite_one., 2008-07-12). I considered and rejected several possible alternatives: 1. Keep a count of UNINTERESTING commits in the queue. This requires managing the count not only when removing an item from the queue, but also when marking an item as UNINTERESTING. That requires touching the other functions which mark commits, and would require knowing quickly which commits are in the queue (lookup in the queue is linear, so we would need an auxiliary structure or to also maintain an IN_QUEUE flag in each commit object). 2. Keep a separate list of interesting commits. Drop items from it when they are dropped from the queue, or if they become UNINTERESTING. This again suffers from extra complexity to maintain the list, not to mention CPU and memory. 3. Use a better data structure for the queue. This is something that could help the fix in fce87ae, because we order the queue by recency, and it is about inserting quickly in recency order. So a normal priority queue would help there. But here, we cannot disturb the order of the queue, which makes things harder. We really do need an auxiliary index to track the flag we care about, which is basically option (2) above. The "cache" trick is simple, and the numbers above show that it works well in practice. This is because the length of time it takes to find an interesting commit is proportional to the length of time it will remain cached (i.e., if we have to walk a long way to find it, it also means we have to pop a lot of elements in the queue until we get rid of it and have to find another interesting commit). The worst case is still quadratic, though. We could have `N` uninteresting commits at the front of the queue, followed by `N` interesting commits, where commit `i` has parent `i+N`. When we pop commit `i`, we will notice that the parent of the next commit, `i+1+N` is still interesting and cache it. But then handling commit `i+1`, we will mark its parent `i+1+N` uninteresting, and immediately invalidate our cache. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-17 22:11:04 +00:00
if (!everybody_uninteresting(src, interesting_cache))
return SLOP;
/* Ok, we're closing in.. */
return slop-1;
Add "--show-all" revision walker flag for debugging It's really not very easy to visualize the commit walker, because - on purpose - it obvously doesn't show the uninteresting commits! This adds a "--show-all" flag to the revision walker, which will make it show uninteresting commits too, and they'll have a '^' in front of them (it also fixes a logic error for !verbose_header for boundary commits - we should show the '-' even if left_right isn't shown). A separate patch to gitk to teach it the new '^' was sent to paulus. With the change in place, it actually is interesting even for the cases that git doesn't have any problems with, ie for the kernel you can do: gitk -d --show-all v2.6.24.. and you see just how far down it has to parse things to see it all. The use of "-d" is a good idea, since the date-ordered toposort is much better at showing why it goes deep down (ie the date of some of those commits after 2.6.24 is much older, because they were merged from trees that weren't rebased). So I think this is a useful feature even for non-debugging - just to visualize what git does internally more. When it actually breaks out due to the "everybody_uninteresting()" case, it adds the uninteresting commits (both the one it's looking at now, and the list of pending ones) to the list This way, we really list *all* the commits we've looked at. Because we now end up listing commits we may not even have been parsed at all "show_log" and "show_commit" need to protect against commits that don't have a commit buffer entry. That second part is debatable just how it should work. Maybe we shouldn't show such entries at all (with this patch those entries do get shown, they just don't get any message shown with them). But I think this is a useful case. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-09 22:02:07 +00:00
}
/*
* "rev-list --ancestry-path A..B" computes commits that are ancestors
* of B but not ancestors of A but further limits the result to those
* that are descendants of A. This takes the list of bottom commits and
* the result of "A..B" without --ancestry-path, and limits the latter
* further to the ones that can reach one of the commits in "bottom".
*/
static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
{
struct commit_list *p;
struct commit_list *rlist = NULL;
int made_progress;
/*
* Reverse the list so that it will be likely that we would
* process parents before children.
*/
for (p = list; p; p = p->next)
commit_list_insert(p->item, &rlist);
for (p = bottom; p; p = p->next)
p->item->object.flags |= TMP_MARK;
/*
* Mark the ones that can reach bottom commits in "list",
* in a bottom-up fashion.
*/
do {
made_progress = 0;
for (p = rlist; p; p = p->next) {
struct commit *c = p->item;
struct commit_list *parents;
if (c->object.flags & (TMP_MARK | UNINTERESTING))
continue;
for (parents = c->parents;
parents;
parents = parents->next) {
if (!(parents->item->object.flags & TMP_MARK))
continue;
c->object.flags |= TMP_MARK;
made_progress = 1;
break;
}
}
} while (made_progress);
/*
* NEEDSWORK: decide if we want to remove parents that are
* not marked with TMP_MARK from commit->parents for commits
* in the resulting list. We may not want to do that, though.
*/
/*
* The ones that are not marked with TMP_MARK are uninteresting
*/
for (p = list; p; p = p->next) {
struct commit *c = p->item;
if (c->object.flags & TMP_MARK)
continue;
c->object.flags |= UNINTERESTING;
}
/* We are done with the TMP_MARK */
for (p = list; p; p = p->next)
p->item->object.flags &= ~TMP_MARK;
for (p = bottom; p; p = p->next)
p->item->object.flags &= ~TMP_MARK;
free_commit_list(rlist);
}
/*
* Before walking the history, keep the set of "negative" refs the
* caller has asked to exclude.
*
* This is used to compute "rev-list --ancestry-path A..B", as we need
* to filter the result of "A..B" further to the ones that can actually
* reach A.
*/
static struct commit_list *collect_bottom_commits(struct commit_list *list)
{
struct commit_list *elem, *bottom = NULL;
for (elem = list; elem; elem = elem->next)
if (elem->item->object.flags & BOTTOM)
commit_list_insert(elem->item, &bottom);
return bottom;
}
/* Assumes either left_only or right_only is set */
static void limit_left_right(struct commit_list *list, struct rev_info *revs)
{
struct commit_list *p;
for (p = list; p; p = p->next) {
struct commit *commit = p->item;
if (revs->right_only) {
if (commit->object.flags & SYMMETRIC_LEFT)
commit->object.flags |= SHOWN;
} else /* revs->left_only is set */
if (!(commit->object.flags & SYMMETRIC_LEFT))
commit->object.flags |= SHOWN;
}
}
static int limit_list(struct rev_info *revs)
{
int slop = SLOP;
timestamp_t date = TIME_MAX;
revision: free remainder of old commit list in limit_list limit_list() iterates over the original revs->commits list, and consumes many of its entries via pop_commit. However we might stop iterating over the list early (e.g. if we realise that the rest of the list is uninteresting). If we do stop iterating early, list will be pointing to the unconsumed portion of revs->commits - and we need to free this list to avoid a leak. (revs->commits itself will be an invalid pointer: it will have been free'd during the first pop_commit.) However the list pointer is later reused to iterate over our new list, but only for the limiting_can_increase_treesame() branch. We therefore need to introduce a new variable for that branch - and while we're here we can rename the original list to original_list as that makes its purpose more obvious. This leak was found while running t0090. It's not likely to be very impactful, but it can happen quite early during some checkout invocations, and hence seems to be worth fixing: Direct leak of 16 byte(s) in 1 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x7175d6 in commit_list_insert commit.c:540:33 #4 0x71800f in commit_list_insert_by_date commit.c:604:9 #5 0x8f8d2e in process_parents revision.c:1128:5 #6 0x8f2f2c in limit_list revision.c:1418:7 #7 0x8f210e in prepare_revision_walk revision.c:3577:7 #8 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #9 0x512f05 in switch_branches builtin/checkout.c:1250:3 #10 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #11 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #12 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #13 0x4cd91d in run_builtin git.c:467:11 #14 0x4cb5f3 in handle_builtin git.c:719:3 #15 0x4ccf47 in run_argv git.c:808:4 #16 0x4caf49 in cmd_main git.c:939:19 #17 0x69dc0e in main common-main.c:52:11 #18 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Indirect leak of 48 byte(s) in 3 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x717de6 in commit_list_append commit.c:1609:35 #4 0x8f1f9b in prepare_revision_walk revision.c:3554:12 #5 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #6 0x512f05 in switch_branches builtin/checkout.c:1250:3 #7 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #8 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #9 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #10 0x4cd91d in run_builtin git.c:467:11 #11 0x4cb5f3 in handle_builtin git.c:719:3 #12 0x4ccf47 in run_argv git.c:808:4 #13 0x4caf49 in cmd_main git.c:939:19 #14 0x69dc0e in main common-main.c:52:11 #15 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Signed-off-by: Andrzej Hunt <ajrhunt@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-25 14:16:08 +00:00
struct commit_list *original_list = revs->commits;
struct commit_list *newlist = NULL;
struct commit_list **p = &newlist;
struct commit_list *bottom = NULL;
limit_list: avoid quadratic behavior from still_interesting When we are limiting a rev-list traversal due to UNINTERESTING refs, we have to walk down the tips (both interesting and uninteresting) to find where they intersect. We keep a queue of commits to examine, pop commits off the queue one by one, and potentially add their parents. The size of the queue will naturally fluctuate based on the "width" of the history graph; i.e., the number of simultaneous lines of development. But for the most part it will stay in the same ballpark as the initial number of tips we fed, shrinking over time (as we hit common ancestors of the tips). So roughly speaking, if we start with `N` tips, we'll spend much of the time with a queue around `N` items. For each UNINTERESTING commit we pop, we call still_interesting to check whether marking its parents as UNINTERESTING has made the whole queue uninteresting (in which case we can quit early). Because the queue is stored as a linked list, this is `O(N)`, where `N` is the number of items in the queue. So processing a queue with `N` commits marked UNINTERESTING (and one or more interesting commits) will take `O(N^2)`. If you feed a lot of positive tips, this isn't a problem. They aren't UNINTERESTING, so they don't incur the still_interesting check. It also isn't a problem if you traverse from an interesting tip to some UNINTERESTING bases. We order the queue by recency, so the interesting commits stay at the front of the queue as we walk down them. The linear check can exit early as soon as it sees one interesting commit left in the queue. But if you want to know whether an older commit is reachable from a set of newer tips, we end up processing in the opposite direction: from the UNINTERESTING ones down to the interesting one. This may happen when we call: git rev-list $commits --not --all in check_everything_connected after a fetch. If we fetched something much older than most of our refs, and if we have a large number of refs, the traversal cost is dominated by the quadratic behavior. These commands simulate the connectivity check of such a fetch, when you have `$n` distinct refs in the receiver: # positive ref is 100,000 commits deep git rev-list --all | head -100000 | tail -1 >input # huge number of more recent negative refs git rev-list --all | head -$n | sed s/^/^/ >>input time git rev-list --stdin <input Here are timings for various `n` on the linux.git repository. The `n=1` case provides a baseline for just walking the commits, which lets us see the still_interesting overhead. The times marked with `+` subtract that baseline to show just the extra time growth due to the large number of refs. The `x` numbers show the slowdown of the adjusted time versus the prior trial. n | before | after -------------------------------------------------------- 1 | 0.991s | 0.848s 10000 | 1.120s (+0.129s) | 0.885s (+0.037s) 20000 | 1.451s (+0.460s, 3.5x) | 0.923s (+0.075s, 2.0x) 40000 | 2.731s (+1.740s, 3.8x) | 0.994s (+0.146s, 1.9x) 80000 | 8.235s (+7.244s, 4.2x) | 1.123s (+0.275s, 1.9x) Each trial doubles `n`, so you can see the quadratic (`4x`) behavior before this patch. Afterwards, we have a roughly linear relationship. The implementation is fairly straightforward. Whenever we do the linear search, we cache the interesting commit we find, and next time check it before doing another linear search. If that commit is removed from the list or becomes UNINTERESTING itself, then we fall back to the linear search. This is very similar to the trick used by fce87ae (Fix quadratic performance in rewrite_one., 2008-07-12). I considered and rejected several possible alternatives: 1. Keep a count of UNINTERESTING commits in the queue. This requires managing the count not only when removing an item from the queue, but also when marking an item as UNINTERESTING. That requires touching the other functions which mark commits, and would require knowing quickly which commits are in the queue (lookup in the queue is linear, so we would need an auxiliary structure or to also maintain an IN_QUEUE flag in each commit object). 2. Keep a separate list of interesting commits. Drop items from it when they are dropped from the queue, or if they become UNINTERESTING. This again suffers from extra complexity to maintain the list, not to mention CPU and memory. 3. Use a better data structure for the queue. This is something that could help the fix in fce87ae, because we order the queue by recency, and it is about inserting quickly in recency order. So a normal priority queue would help there. But here, we cannot disturb the order of the queue, which makes things harder. We really do need an auxiliary index to track the flag we care about, which is basically option (2) above. The "cache" trick is simple, and the numbers above show that it works well in practice. This is because the length of time it takes to find an interesting commit is proportional to the length of time it will remain cached (i.e., if we have to walk a long way to find it, it also means we have to pop a lot of elements in the queue until we get rid of it and have to find another interesting commit). The worst case is still quadratic, though. We could have `N` uninteresting commits at the front of the queue, followed by `N` interesting commits, where commit `i` has parent `i+N`. When we pop commit `i`, we will notice that the parent of the next commit, `i+1+N` is still interesting and cache it. But then handling commit `i+1`, we will mark its parent `i+1+N` uninteresting, and immediately invalidate our cache. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-17 22:11:04 +00:00
struct commit *interesting_cache = NULL;
if (revs->ancestry_path) {
revision: free remainder of old commit list in limit_list limit_list() iterates over the original revs->commits list, and consumes many of its entries via pop_commit. However we might stop iterating over the list early (e.g. if we realise that the rest of the list is uninteresting). If we do stop iterating early, list will be pointing to the unconsumed portion of revs->commits - and we need to free this list to avoid a leak. (revs->commits itself will be an invalid pointer: it will have been free'd during the first pop_commit.) However the list pointer is later reused to iterate over our new list, but only for the limiting_can_increase_treesame() branch. We therefore need to introduce a new variable for that branch - and while we're here we can rename the original list to original_list as that makes its purpose more obvious. This leak was found while running t0090. It's not likely to be very impactful, but it can happen quite early during some checkout invocations, and hence seems to be worth fixing: Direct leak of 16 byte(s) in 1 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x7175d6 in commit_list_insert commit.c:540:33 #4 0x71800f in commit_list_insert_by_date commit.c:604:9 #5 0x8f8d2e in process_parents revision.c:1128:5 #6 0x8f2f2c in limit_list revision.c:1418:7 #7 0x8f210e in prepare_revision_walk revision.c:3577:7 #8 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #9 0x512f05 in switch_branches builtin/checkout.c:1250:3 #10 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #11 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #12 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #13 0x4cd91d in run_builtin git.c:467:11 #14 0x4cb5f3 in handle_builtin git.c:719:3 #15 0x4ccf47 in run_argv git.c:808:4 #16 0x4caf49 in cmd_main git.c:939:19 #17 0x69dc0e in main common-main.c:52:11 #18 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Indirect leak of 48 byte(s) in 3 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x717de6 in commit_list_append commit.c:1609:35 #4 0x8f1f9b in prepare_revision_walk revision.c:3554:12 #5 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #6 0x512f05 in switch_branches builtin/checkout.c:1250:3 #7 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #8 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #9 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #10 0x4cd91d in run_builtin git.c:467:11 #11 0x4cb5f3 in handle_builtin git.c:719:3 #12 0x4ccf47 in run_argv git.c:808:4 #13 0x4caf49 in cmd_main git.c:939:19 #14 0x69dc0e in main common-main.c:52:11 #15 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Signed-off-by: Andrzej Hunt <ajrhunt@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-25 14:16:08 +00:00
bottom = collect_bottom_commits(original_list);
if (!bottom)
die("--ancestry-path given but there are no bottom commits");
}
revision: free remainder of old commit list in limit_list limit_list() iterates over the original revs->commits list, and consumes many of its entries via pop_commit. However we might stop iterating over the list early (e.g. if we realise that the rest of the list is uninteresting). If we do stop iterating early, list will be pointing to the unconsumed portion of revs->commits - and we need to free this list to avoid a leak. (revs->commits itself will be an invalid pointer: it will have been free'd during the first pop_commit.) However the list pointer is later reused to iterate over our new list, but only for the limiting_can_increase_treesame() branch. We therefore need to introduce a new variable for that branch - and while we're here we can rename the original list to original_list as that makes its purpose more obvious. This leak was found while running t0090. It's not likely to be very impactful, but it can happen quite early during some checkout invocations, and hence seems to be worth fixing: Direct leak of 16 byte(s) in 1 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x7175d6 in commit_list_insert commit.c:540:33 #4 0x71800f in commit_list_insert_by_date commit.c:604:9 #5 0x8f8d2e in process_parents revision.c:1128:5 #6 0x8f2f2c in limit_list revision.c:1418:7 #7 0x8f210e in prepare_revision_walk revision.c:3577:7 #8 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #9 0x512f05 in switch_branches builtin/checkout.c:1250:3 #10 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #11 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #12 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #13 0x4cd91d in run_builtin git.c:467:11 #14 0x4cb5f3 in handle_builtin git.c:719:3 #15 0x4ccf47 in run_argv git.c:808:4 #16 0x4caf49 in cmd_main git.c:939:19 #17 0x69dc0e in main common-main.c:52:11 #18 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Indirect leak of 48 byte(s) in 3 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x717de6 in commit_list_append commit.c:1609:35 #4 0x8f1f9b in prepare_revision_walk revision.c:3554:12 #5 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #6 0x512f05 in switch_branches builtin/checkout.c:1250:3 #7 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #8 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #9 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #10 0x4cd91d in run_builtin git.c:467:11 #11 0x4cb5f3 in handle_builtin git.c:719:3 #12 0x4ccf47 in run_argv git.c:808:4 #13 0x4caf49 in cmd_main git.c:939:19 #14 0x69dc0e in main common-main.c:52:11 #15 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Signed-off-by: Andrzej Hunt <ajrhunt@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-25 14:16:08 +00:00
while (original_list) {
struct commit *commit = pop_commit(&original_list);
struct object *obj = &commit->object;
show_early_output_fn_t show;
limit_list: avoid quadratic behavior from still_interesting When we are limiting a rev-list traversal due to UNINTERESTING refs, we have to walk down the tips (both interesting and uninteresting) to find where they intersect. We keep a queue of commits to examine, pop commits off the queue one by one, and potentially add their parents. The size of the queue will naturally fluctuate based on the "width" of the history graph; i.e., the number of simultaneous lines of development. But for the most part it will stay in the same ballpark as the initial number of tips we fed, shrinking over time (as we hit common ancestors of the tips). So roughly speaking, if we start with `N` tips, we'll spend much of the time with a queue around `N` items. For each UNINTERESTING commit we pop, we call still_interesting to check whether marking its parents as UNINTERESTING has made the whole queue uninteresting (in which case we can quit early). Because the queue is stored as a linked list, this is `O(N)`, where `N` is the number of items in the queue. So processing a queue with `N` commits marked UNINTERESTING (and one or more interesting commits) will take `O(N^2)`. If you feed a lot of positive tips, this isn't a problem. They aren't UNINTERESTING, so they don't incur the still_interesting check. It also isn't a problem if you traverse from an interesting tip to some UNINTERESTING bases. We order the queue by recency, so the interesting commits stay at the front of the queue as we walk down them. The linear check can exit early as soon as it sees one interesting commit left in the queue. But if you want to know whether an older commit is reachable from a set of newer tips, we end up processing in the opposite direction: from the UNINTERESTING ones down to the interesting one. This may happen when we call: git rev-list $commits --not --all in check_everything_connected after a fetch. If we fetched something much older than most of our refs, and if we have a large number of refs, the traversal cost is dominated by the quadratic behavior. These commands simulate the connectivity check of such a fetch, when you have `$n` distinct refs in the receiver: # positive ref is 100,000 commits deep git rev-list --all | head -100000 | tail -1 >input # huge number of more recent negative refs git rev-list --all | head -$n | sed s/^/^/ >>input time git rev-list --stdin <input Here are timings for various `n` on the linux.git repository. The `n=1` case provides a baseline for just walking the commits, which lets us see the still_interesting overhead. The times marked with `+` subtract that baseline to show just the extra time growth due to the large number of refs. The `x` numbers show the slowdown of the adjusted time versus the prior trial. n | before | after -------------------------------------------------------- 1 | 0.991s | 0.848s 10000 | 1.120s (+0.129s) | 0.885s (+0.037s) 20000 | 1.451s (+0.460s, 3.5x) | 0.923s (+0.075s, 2.0x) 40000 | 2.731s (+1.740s, 3.8x) | 0.994s (+0.146s, 1.9x) 80000 | 8.235s (+7.244s, 4.2x) | 1.123s (+0.275s, 1.9x) Each trial doubles `n`, so you can see the quadratic (`4x`) behavior before this patch. Afterwards, we have a roughly linear relationship. The implementation is fairly straightforward. Whenever we do the linear search, we cache the interesting commit we find, and next time check it before doing another linear search. If that commit is removed from the list or becomes UNINTERESTING itself, then we fall back to the linear search. This is very similar to the trick used by fce87ae (Fix quadratic performance in rewrite_one., 2008-07-12). I considered and rejected several possible alternatives: 1. Keep a count of UNINTERESTING commits in the queue. This requires managing the count not only when removing an item from the queue, but also when marking an item as UNINTERESTING. That requires touching the other functions which mark commits, and would require knowing quickly which commits are in the queue (lookup in the queue is linear, so we would need an auxiliary structure or to also maintain an IN_QUEUE flag in each commit object). 2. Keep a separate list of interesting commits. Drop items from it when they are dropped from the queue, or if they become UNINTERESTING. This again suffers from extra complexity to maintain the list, not to mention CPU and memory. 3. Use a better data structure for the queue. This is something that could help the fix in fce87ae, because we order the queue by recency, and it is about inserting quickly in recency order. So a normal priority queue would help there. But here, we cannot disturb the order of the queue, which makes things harder. We really do need an auxiliary index to track the flag we care about, which is basically option (2) above. The "cache" trick is simple, and the numbers above show that it works well in practice. This is because the length of time it takes to find an interesting commit is proportional to the length of time it will remain cached (i.e., if we have to walk a long way to find it, it also means we have to pop a lot of elements in the queue until we get rid of it and have to find another interesting commit). The worst case is still quadratic, though. We could have `N` uninteresting commits at the front of the queue, followed by `N` interesting commits, where commit `i` has parent `i+N`. When we pop commit `i`, we will notice that the parent of the next commit, `i+1+N` is still interesting and cache it. But then handling commit `i+1`, we will mark its parent `i+1+N` uninteresting, and immediately invalidate our cache. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-17 22:11:04 +00:00
if (commit == interesting_cache)
interesting_cache = NULL;
if (revs->max_age != -1 && (commit->date < revs->max_age))
obj->flags |= UNINTERESTING;
revision: free remainder of old commit list in limit_list limit_list() iterates over the original revs->commits list, and consumes many of its entries via pop_commit. However we might stop iterating over the list early (e.g. if we realise that the rest of the list is uninteresting). If we do stop iterating early, list will be pointing to the unconsumed portion of revs->commits - and we need to free this list to avoid a leak. (revs->commits itself will be an invalid pointer: it will have been free'd during the first pop_commit.) However the list pointer is later reused to iterate over our new list, but only for the limiting_can_increase_treesame() branch. We therefore need to introduce a new variable for that branch - and while we're here we can rename the original list to original_list as that makes its purpose more obvious. This leak was found while running t0090. It's not likely to be very impactful, but it can happen quite early during some checkout invocations, and hence seems to be worth fixing: Direct leak of 16 byte(s) in 1 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x7175d6 in commit_list_insert commit.c:540:33 #4 0x71800f in commit_list_insert_by_date commit.c:604:9 #5 0x8f8d2e in process_parents revision.c:1128:5 #6 0x8f2f2c in limit_list revision.c:1418:7 #7 0x8f210e in prepare_revision_walk revision.c:3577:7 #8 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #9 0x512f05 in switch_branches builtin/checkout.c:1250:3 #10 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #11 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #12 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #13 0x4cd91d in run_builtin git.c:467:11 #14 0x4cb5f3 in handle_builtin git.c:719:3 #15 0x4ccf47 in run_argv git.c:808:4 #16 0x4caf49 in cmd_main git.c:939:19 #17 0x69dc0e in main common-main.c:52:11 #18 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Indirect leak of 48 byte(s) in 3 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x717de6 in commit_list_append commit.c:1609:35 #4 0x8f1f9b in prepare_revision_walk revision.c:3554:12 #5 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #6 0x512f05 in switch_branches builtin/checkout.c:1250:3 #7 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #8 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #9 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #10 0x4cd91d in run_builtin git.c:467:11 #11 0x4cb5f3 in handle_builtin git.c:719:3 #12 0x4ccf47 in run_argv git.c:808:4 #13 0x4caf49 in cmd_main git.c:939:19 #14 0x69dc0e in main common-main.c:52:11 #15 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Signed-off-by: Andrzej Hunt <ajrhunt@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-25 14:16:08 +00:00
if (process_parents(revs, commit, &original_list, NULL) < 0)
return -1;
if (obj->flags & UNINTERESTING) {
mark_parents_uninteresting(revs, commit);
revision: free remainder of old commit list in limit_list limit_list() iterates over the original revs->commits list, and consumes many of its entries via pop_commit. However we might stop iterating over the list early (e.g. if we realise that the rest of the list is uninteresting). If we do stop iterating early, list will be pointing to the unconsumed portion of revs->commits - and we need to free this list to avoid a leak. (revs->commits itself will be an invalid pointer: it will have been free'd during the first pop_commit.) However the list pointer is later reused to iterate over our new list, but only for the limiting_can_increase_treesame() branch. We therefore need to introduce a new variable for that branch - and while we're here we can rename the original list to original_list as that makes its purpose more obvious. This leak was found while running t0090. It's not likely to be very impactful, but it can happen quite early during some checkout invocations, and hence seems to be worth fixing: Direct leak of 16 byte(s) in 1 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x7175d6 in commit_list_insert commit.c:540:33 #4 0x71800f in commit_list_insert_by_date commit.c:604:9 #5 0x8f8d2e in process_parents revision.c:1128:5 #6 0x8f2f2c in limit_list revision.c:1418:7 #7 0x8f210e in prepare_revision_walk revision.c:3577:7 #8 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #9 0x512f05 in switch_branches builtin/checkout.c:1250:3 #10 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #11 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #12 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #13 0x4cd91d in run_builtin git.c:467:11 #14 0x4cb5f3 in handle_builtin git.c:719:3 #15 0x4ccf47 in run_argv git.c:808:4 #16 0x4caf49 in cmd_main git.c:939:19 #17 0x69dc0e in main common-main.c:52:11 #18 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Indirect leak of 48 byte(s) in 3 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x717de6 in commit_list_append commit.c:1609:35 #4 0x8f1f9b in prepare_revision_walk revision.c:3554:12 #5 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #6 0x512f05 in switch_branches builtin/checkout.c:1250:3 #7 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #8 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #9 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #10 0x4cd91d in run_builtin git.c:467:11 #11 0x4cb5f3 in handle_builtin git.c:719:3 #12 0x4ccf47 in run_argv git.c:808:4 #13 0x4caf49 in cmd_main git.c:939:19 #14 0x69dc0e in main common-main.c:52:11 #15 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Signed-off-by: Andrzej Hunt <ajrhunt@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-25 14:16:08 +00:00
slop = still_interesting(original_list, date, slop, &interesting_cache);
if (slop)
Add "--show-all" revision walker flag for debugging It's really not very easy to visualize the commit walker, because - on purpose - it obvously doesn't show the uninteresting commits! This adds a "--show-all" flag to the revision walker, which will make it show uninteresting commits too, and they'll have a '^' in front of them (it also fixes a logic error for !verbose_header for boundary commits - we should show the '-' even if left_right isn't shown). A separate patch to gitk to teach it the new '^' was sent to paulus. With the change in place, it actually is interesting even for the cases that git doesn't have any problems with, ie for the kernel you can do: gitk -d --show-all v2.6.24.. and you see just how far down it has to parse things to see it all. The use of "-d" is a good idea, since the date-ordered toposort is much better at showing why it goes deep down (ie the date of some of those commits after 2.6.24 is much older, because they were merged from trees that weren't rebased). So I think this is a useful feature even for non-debugging - just to visualize what git does internally more. When it actually breaks out due to the "everybody_uninteresting()" case, it adds the uninteresting commits (both the one it's looking at now, and the list of pending ones) to the list This way, we really list *all* the commits we've looked at. Because we now end up listing commits we may not even have been parsed at all "show_log" and "show_commit" need to protect against commits that don't have a commit buffer entry. That second part is debatable just how it should work. Maybe we shouldn't show such entries at all (with this patch those entries do get shown, they just don't get any message shown with them). But I think this is a useful case. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-09 22:02:07 +00:00
continue;
break;
}
if (revs->min_age != -1 && (commit->date > revs->min_age) &&
!revs->line_level_traverse)
continue;
date = commit->date;
p = &commit_list_insert(commit, p)->next;
show = show_early_output;
if (!show)
continue;
show(revs, newlist);
show_early_output = NULL;
}
if (revs->cherry_pick || revs->cherry_mark)
cherry_pick_list(newlist, revs);
if (revs->left_only || revs->right_only)
limit_left_right(newlist, revs);
if (bottom) {
limit_to_ancestry(bottom, newlist);
free_commit_list(bottom);
}
/*
* Check if any commits have become TREESAME by some of their parents
* becoming UNINTERESTING.
*/
revision: free remainder of old commit list in limit_list limit_list() iterates over the original revs->commits list, and consumes many of its entries via pop_commit. However we might stop iterating over the list early (e.g. if we realise that the rest of the list is uninteresting). If we do stop iterating early, list will be pointing to the unconsumed portion of revs->commits - and we need to free this list to avoid a leak. (revs->commits itself will be an invalid pointer: it will have been free'd during the first pop_commit.) However the list pointer is later reused to iterate over our new list, but only for the limiting_can_increase_treesame() branch. We therefore need to introduce a new variable for that branch - and while we're here we can rename the original list to original_list as that makes its purpose more obvious. This leak was found while running t0090. It's not likely to be very impactful, but it can happen quite early during some checkout invocations, and hence seems to be worth fixing: Direct leak of 16 byte(s) in 1 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x7175d6 in commit_list_insert commit.c:540:33 #4 0x71800f in commit_list_insert_by_date commit.c:604:9 #5 0x8f8d2e in process_parents revision.c:1128:5 #6 0x8f2f2c in limit_list revision.c:1418:7 #7 0x8f210e in prepare_revision_walk revision.c:3577:7 #8 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #9 0x512f05 in switch_branches builtin/checkout.c:1250:3 #10 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #11 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #12 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #13 0x4cd91d in run_builtin git.c:467:11 #14 0x4cb5f3 in handle_builtin git.c:719:3 #15 0x4ccf47 in run_argv git.c:808:4 #16 0x4caf49 in cmd_main git.c:939:19 #17 0x69dc0e in main common-main.c:52:11 #18 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Indirect leak of 48 byte(s) in 3 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x717de6 in commit_list_append commit.c:1609:35 #4 0x8f1f9b in prepare_revision_walk revision.c:3554:12 #5 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #6 0x512f05 in switch_branches builtin/checkout.c:1250:3 #7 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #8 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #9 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #10 0x4cd91d in run_builtin git.c:467:11 #11 0x4cb5f3 in handle_builtin git.c:719:3 #12 0x4ccf47 in run_argv git.c:808:4 #13 0x4caf49 in cmd_main git.c:939:19 #14 0x69dc0e in main common-main.c:52:11 #15 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Signed-off-by: Andrzej Hunt <ajrhunt@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-25 14:16:08 +00:00
if (limiting_can_increase_treesame(revs)) {
struct commit_list *list = NULL;
for (list = newlist; list; list = list->next) {
struct commit *c = list->item;
if (c->object.flags & (UNINTERESTING | TREESAME))
continue;
update_treesame(revs, c);
}
revision: free remainder of old commit list in limit_list limit_list() iterates over the original revs->commits list, and consumes many of its entries via pop_commit. However we might stop iterating over the list early (e.g. if we realise that the rest of the list is uninteresting). If we do stop iterating early, list will be pointing to the unconsumed portion of revs->commits - and we need to free this list to avoid a leak. (revs->commits itself will be an invalid pointer: it will have been free'd during the first pop_commit.) However the list pointer is later reused to iterate over our new list, but only for the limiting_can_increase_treesame() branch. We therefore need to introduce a new variable for that branch - and while we're here we can rename the original list to original_list as that makes its purpose more obvious. This leak was found while running t0090. It's not likely to be very impactful, but it can happen quite early during some checkout invocations, and hence seems to be worth fixing: Direct leak of 16 byte(s) in 1 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x7175d6 in commit_list_insert commit.c:540:33 #4 0x71800f in commit_list_insert_by_date commit.c:604:9 #5 0x8f8d2e in process_parents revision.c:1128:5 #6 0x8f2f2c in limit_list revision.c:1418:7 #7 0x8f210e in prepare_revision_walk revision.c:3577:7 #8 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #9 0x512f05 in switch_branches builtin/checkout.c:1250:3 #10 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #11 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #12 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #13 0x4cd91d in run_builtin git.c:467:11 #14 0x4cb5f3 in handle_builtin git.c:719:3 #15 0x4ccf47 in run_argv git.c:808:4 #16 0x4caf49 in cmd_main git.c:939:19 #17 0x69dc0e in main common-main.c:52:11 #18 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Indirect leak of 48 byte(s) in 3 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x717de6 in commit_list_append commit.c:1609:35 #4 0x8f1f9b in prepare_revision_walk revision.c:3554:12 #5 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #6 0x512f05 in switch_branches builtin/checkout.c:1250:3 #7 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #8 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #9 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #10 0x4cd91d in run_builtin git.c:467:11 #11 0x4cb5f3 in handle_builtin git.c:719:3 #12 0x4ccf47 in run_argv git.c:808:4 #13 0x4caf49 in cmd_main git.c:939:19 #14 0x69dc0e in main common-main.c:52:11 #15 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Signed-off-by: Andrzej Hunt <ajrhunt@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-25 14:16:08 +00:00
}
revision: free remainder of old commit list in limit_list limit_list() iterates over the original revs->commits list, and consumes many of its entries via pop_commit. However we might stop iterating over the list early (e.g. if we realise that the rest of the list is uninteresting). If we do stop iterating early, list will be pointing to the unconsumed portion of revs->commits - and we need to free this list to avoid a leak. (revs->commits itself will be an invalid pointer: it will have been free'd during the first pop_commit.) However the list pointer is later reused to iterate over our new list, but only for the limiting_can_increase_treesame() branch. We therefore need to introduce a new variable for that branch - and while we're here we can rename the original list to original_list as that makes its purpose more obvious. This leak was found while running t0090. It's not likely to be very impactful, but it can happen quite early during some checkout invocations, and hence seems to be worth fixing: Direct leak of 16 byte(s) in 1 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x7175d6 in commit_list_insert commit.c:540:33 #4 0x71800f in commit_list_insert_by_date commit.c:604:9 #5 0x8f8d2e in process_parents revision.c:1128:5 #6 0x8f2f2c in limit_list revision.c:1418:7 #7 0x8f210e in prepare_revision_walk revision.c:3577:7 #8 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #9 0x512f05 in switch_branches builtin/checkout.c:1250:3 #10 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #11 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #12 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #13 0x4cd91d in run_builtin git.c:467:11 #14 0x4cb5f3 in handle_builtin git.c:719:3 #15 0x4ccf47 in run_argv git.c:808:4 #16 0x4caf49 in cmd_main git.c:939:19 #17 0x69dc0e in main common-main.c:52:11 #18 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Indirect leak of 48 byte(s) in 3 object(s) allocated from: #0 0x49a85d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x9ac084 in do_xmalloc wrapper.c:41:8 #2 0x9ac05a in xmalloc wrapper.c:62:9 #3 0x717de6 in commit_list_append commit.c:1609:35 #4 0x8f1f9b in prepare_revision_walk revision.c:3554:12 #5 0x514170 in orphaned_commit_warning builtin/checkout.c:1185:6 #6 0x512f05 in switch_branches builtin/checkout.c:1250:3 #7 0x50f8de in checkout_branch builtin/checkout.c:1646:9 #8 0x50ba12 in checkout_main builtin/checkout.c:2003:9 #9 0x5086c0 in cmd_checkout builtin/checkout.c:2055:8 #10 0x4cd91d in run_builtin git.c:467:11 #11 0x4cb5f3 in handle_builtin git.c:719:3 #12 0x4ccf47 in run_argv git.c:808:4 #13 0x4caf49 in cmd_main git.c:939:19 #14 0x69dc0e in main common-main.c:52:11 #15 0x7faaabd0e349 in __libc_start_main (/lib64/libc.so.6+0x24349) Signed-off-by: Andrzej Hunt <ajrhunt@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-25 14:16:08 +00:00
free_commit_list(original_list);
revs->commits = newlist;
return 0;
}
/*
* Add an entry to refs->cmdline with the specified information.
* *name is copied.
*/
revision: keep track of the end-user input from the command line Given a complex set of revision specifiers on the command line, it is too late to look at the flags of the objects in the initial traversal list at the beginning of limit_list() in order to determine what the objects the end-user explicitly listed on the command line were. The process to move objects from the pending array to the traversal list may have marked objects that are not mentioned as UNINTERESTING, when handle_commit() marked the parents of UNINTERESTING commits mentioned on the command line by calling mark_parents_uninteresting(). This made "rev-list --ancestry-path ^A ..." to mistakenly list commits that are descendants of A's parents but that are not descendants of A itself, as ^A from the command line causes A and its parents marked as UNINTERESTING before coming to limit_list(), and we try to enumerate the commits that are descendants of these commits that are UNINTERESTING before we start walking the history. It actually is too late even if we inspected the pending object array before calling prepare_revision_walk(), as some of the same objects might have been mentioned twice, once as positive and another time as negative. The "rev-list --some-option A --not --all" command may want to notice, even if the resulting set is empty, that the user showed some interest in "A" and do something special about it. Prepare a separate array to keep track of what syntactic element was used to cause each object to appear in the pending array from the command line, and populate it as setup_revisions() parses the command line. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-26 00:35:39 +00:00
static void add_rev_cmdline(struct rev_info *revs,
struct object *item,
const char *name,
int whence,
unsigned flags)
{
struct rev_cmdline_info *info = &revs->cmdline;
unsigned int nr = info->nr;
revision: keep track of the end-user input from the command line Given a complex set of revision specifiers on the command line, it is too late to look at the flags of the objects in the initial traversal list at the beginning of limit_list() in order to determine what the objects the end-user explicitly listed on the command line were. The process to move objects from the pending array to the traversal list may have marked objects that are not mentioned as UNINTERESTING, when handle_commit() marked the parents of UNINTERESTING commits mentioned on the command line by calling mark_parents_uninteresting(). This made "rev-list --ancestry-path ^A ..." to mistakenly list commits that are descendants of A's parents but that are not descendants of A itself, as ^A from the command line causes A and its parents marked as UNINTERESTING before coming to limit_list(), and we try to enumerate the commits that are descendants of these commits that are UNINTERESTING before we start walking the history. It actually is too late even if we inspected the pending object array before calling prepare_revision_walk(), as some of the same objects might have been mentioned twice, once as positive and another time as negative. The "rev-list --some-option A --not --all" command may want to notice, even if the resulting set is empty, that the user showed some interest in "A" and do something special about it. Prepare a separate array to keep track of what syntactic element was used to cause each object to appear in the pending array from the command line, and populate it as setup_revisions() parses the command line. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-26 00:35:39 +00:00
ALLOC_GROW(info->rev, nr + 1, info->alloc);
info->rev[nr].item = item;
info->rev[nr].name = xstrdup(name);
revision: keep track of the end-user input from the command line Given a complex set of revision specifiers on the command line, it is too late to look at the flags of the objects in the initial traversal list at the beginning of limit_list() in order to determine what the objects the end-user explicitly listed on the command line were. The process to move objects from the pending array to the traversal list may have marked objects that are not mentioned as UNINTERESTING, when handle_commit() marked the parents of UNINTERESTING commits mentioned on the command line by calling mark_parents_uninteresting(). This made "rev-list --ancestry-path ^A ..." to mistakenly list commits that are descendants of A's parents but that are not descendants of A itself, as ^A from the command line causes A and its parents marked as UNINTERESTING before coming to limit_list(), and we try to enumerate the commits that are descendants of these commits that are UNINTERESTING before we start walking the history. It actually is too late even if we inspected the pending object array before calling prepare_revision_walk(), as some of the same objects might have been mentioned twice, once as positive and another time as negative. The "rev-list --some-option A --not --all" command may want to notice, even if the resulting set is empty, that the user showed some interest in "A" and do something special about it. Prepare a separate array to keep track of what syntactic element was used to cause each object to appear in the pending array from the command line, and populate it as setup_revisions() parses the command line. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-26 00:35:39 +00:00
info->rev[nr].whence = whence;
info->rev[nr].flags = flags;
info->nr++;
}
static void add_rev_cmdline_list(struct rev_info *revs,
struct commit_list *commit_list,
int whence,
unsigned flags)
{
while (commit_list) {
struct object *object = &commit_list->item->object;
add_rev_cmdline(revs, object, oid_to_hex(&object->oid),
whence, flags);
commit_list = commit_list->next;
}
}
struct all_refs_cb {
int all_flags;
int warned_bad_reflog;
struct rev_info *all_revs;
const char *name_for_errormsg;
struct worktree *wt;
};
int ref_excluded(struct string_list *ref_excludes, const char *path)
{
struct string_list_item *item;
if (!ref_excludes)
return 0;
for_each_string_list_item(item, ref_excludes) {
if (!wildmatch(item->string, path, 0))
return 1;
}
return 0;
}
static int handle_one_ref(const char *path, const struct object_id *oid,
int flag, void *cb_data)
{
struct all_refs_cb *cb = cb_data;
struct object *object;
if (ref_excluded(cb->all_revs->ref_excludes, path))
return 0;
object = get_reference(cb->all_revs, path, oid, cb->all_flags);
revision: keep track of the end-user input from the command line Given a complex set of revision specifiers on the command line, it is too late to look at the flags of the objects in the initial traversal list at the beginning of limit_list() in order to determine what the objects the end-user explicitly listed on the command line were. The process to move objects from the pending array to the traversal list may have marked objects that are not mentioned as UNINTERESTING, when handle_commit() marked the parents of UNINTERESTING commits mentioned on the command line by calling mark_parents_uninteresting(). This made "rev-list --ancestry-path ^A ..." to mistakenly list commits that are descendants of A's parents but that are not descendants of A itself, as ^A from the command line causes A and its parents marked as UNINTERESTING before coming to limit_list(), and we try to enumerate the commits that are descendants of these commits that are UNINTERESTING before we start walking the history. It actually is too late even if we inspected the pending object array before calling prepare_revision_walk(), as some of the same objects might have been mentioned twice, once as positive and another time as negative. The "rev-list --some-option A --not --all" command may want to notice, even if the resulting set is empty, that the user showed some interest in "A" and do something special about it. Prepare a separate array to keep track of what syntactic element was used to cause each object to appear in the pending array from the command line, and populate it as setup_revisions() parses the command line. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-26 00:35:39 +00:00
add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
add_pending_object(cb->all_revs, object, path);
return 0;
}
static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
unsigned flags)
{
cb->all_revs = revs;
cb->all_flags = flags;
revs->rev_input_given = 1;
cb->wt = NULL;
}
void clear_ref_exclusion(struct string_list **ref_excludes_p)
{
if (*ref_excludes_p) {
string_list_clear(*ref_excludes_p, 0);
free(*ref_excludes_p);
}
*ref_excludes_p = NULL;
}
void add_ref_exclusion(struct string_list **ref_excludes_p, const char *exclude)
{
if (!*ref_excludes_p) {
CALLOC_ARRAY(*ref_excludes_p, 1);
(*ref_excludes_p)->strdup_strings = 1;
}
string_list_append(*ref_excludes_p, exclude);
}
static void handle_refs(struct ref_store *refs,
struct rev_info *revs, unsigned flags,
int (*for_each)(struct ref_store *, each_ref_fn, void *))
{
struct all_refs_cb cb;
if (!refs) {
/* this could happen with uninitialized submodules */
return;
}
init_all_refs_cb(&cb, revs, flags);
for_each(refs, handle_one_ref, &cb);
}
static void handle_one_reflog_commit(struct object_id *oid, void *cb_data)
{
struct all_refs_cb *cb = cb_data;
if (!is_null_oid(oid)) {
struct object *o = parse_object(cb->all_revs->repo, oid);
if (o) {
o->flags |= cb->all_flags;
revision: keep track of the end-user input from the command line Given a complex set of revision specifiers on the command line, it is too late to look at the flags of the objects in the initial traversal list at the beginning of limit_list() in order to determine what the objects the end-user explicitly listed on the command line were. The process to move objects from the pending array to the traversal list may have marked objects that are not mentioned as UNINTERESTING, when handle_commit() marked the parents of UNINTERESTING commits mentioned on the command line by calling mark_parents_uninteresting(). This made "rev-list --ancestry-path ^A ..." to mistakenly list commits that are descendants of A's parents but that are not descendants of A itself, as ^A from the command line causes A and its parents marked as UNINTERESTING before coming to limit_list(), and we try to enumerate the commits that are descendants of these commits that are UNINTERESTING before we start walking the history. It actually is too late even if we inspected the pending object array before calling prepare_revision_walk(), as some of the same objects might have been mentioned twice, once as positive and another time as negative. The "rev-list --some-option A --not --all" command may want to notice, even if the resulting set is empty, that the user showed some interest in "A" and do something special about it. Prepare a separate array to keep track of what syntactic element was used to cause each object to appear in the pending array from the command line, and populate it as setup_revisions() parses the command line. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-26 00:35:39 +00:00
/* ??? CMDLINEFLAGS ??? */
add_pending_object(cb->all_revs, o, "");
}
else if (!cb->warned_bad_reflog) {
warning("reflog of '%s' references pruned commits",
cb->name_for_errormsg);
cb->warned_bad_reflog = 1;
}
}
}
static int handle_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
const char *email, timestamp_t timestamp, int tz,
const char *message, void *cb_data)
{
handle_one_reflog_commit(ooid, cb_data);
handle_one_reflog_commit(noid, cb_data);
return 0;
}
static int handle_one_reflog(const char *refname_in_wt,
const struct object_id *oid,
int flag, void *cb_data)
{
struct all_refs_cb *cb = cb_data;
struct strbuf refname = STRBUF_INIT;
cb->warned_bad_reflog = 0;
strbuf_worktree_ref(cb->wt, &refname, refname_in_wt);
cb->name_for_errormsg = refname.buf;
refs_for_each_reflog_ent(get_main_ref_store(the_repository),
refname.buf,
handle_one_reflog_ent, cb_data);
strbuf_release(&refname);
return 0;
}
static void add_other_reflogs_to_pending(struct all_refs_cb *cb)
{
struct worktree **worktrees, **p;
worktrees = get_worktrees();
for (p = worktrees; *p; p++) {
struct worktree *wt = *p;
if (wt->is_current)
continue;
cb->wt = wt;
refs_for_each_reflog(get_worktree_ref_store(wt),
handle_one_reflog,
cb);
}
free_worktrees(worktrees);
}
void add_reflogs_to_pending(struct rev_info *revs, unsigned flags)
{
struct all_refs_cb cb;
cb.all_revs = revs;
cb.all_flags = flags;
cb.wt = NULL;
for_each_reflog(handle_one_reflog, &cb);
if (!revs->single_worktree)
add_other_reflogs_to_pending(&cb);
}
static void add_cache_tree(struct cache_tree *it, struct rev_info *revs,
struct strbuf *path, unsigned int flags)
{
size_t baselen = path->len;
int i;
if (it->entry_count >= 0) {
struct tree *tree = lookup_tree(revs->repo, &it->oid);
tree->object.flags |= flags;
add_pending_object_with_path(revs, &tree->object, "",
040000, path->buf);
}
for (i = 0; i < it->subtree_nr; i++) {
struct cache_tree_sub *sub = it->down[i];
strbuf_addf(path, "%s%s", baselen ? "/" : "", sub->name);
add_cache_tree(sub->cache_tree, revs, path, flags);
strbuf_setlen(path, baselen);
}
}
static void do_add_index_objects_to_pending(struct rev_info *revs,
struct index_state *istate,
unsigned int flags)
{
int i;
/* TODO: audit for interaction with sparse-index. */
ensure_full_index(istate);
for (i = 0; i < istate->cache_nr; i++) {
struct cache_entry *ce = istate->cache[i];
struct blob *blob;
if (S_ISGITLINK(ce->ce_mode))
continue;
blob = lookup_blob(revs->repo, &ce->oid);
if (!blob)
die("unable to add index blob to traversal");
blob->object.flags |= flags;
add_pending_object_with_path(revs, &blob->object, "",
ce->ce_mode, ce->name);
}
if (istate->cache_tree) {
struct strbuf path = STRBUF_INIT;
add_cache_tree(istate->cache_tree, revs, &path, flags);
strbuf_release(&path);
}
}
void add_index_objects_to_pending(struct rev_info *revs, unsigned int flags)
{
struct worktree **worktrees, **p;
repo_read_index(revs->repo);
do_add_index_objects_to_pending(revs, revs->repo->index, flags);
if (revs->single_worktree)
return;
worktrees = get_worktrees();
for (p = worktrees; *p; p++) {
struct worktree *wt = *p;
struct index_state istate = { NULL };
if (wt->is_current)
continue; /* current index already taken care of */
if (read_index_from(&istate,
read-cache: fix reading the shared index for other repos read_index_from() takes a path argument for the location of the index file. For reading the shared index in split index mode however it just ignores that path argument, and reads it from the gitdir of the current repository. This works as long as an index in the_repository is read. Once that changes, such as when we read the index of a submodule, or of a different working tree than the current one, the gitdir of the_repository will no longer contain the appropriate shared index, and git will fail to read it. For example t3007-ls-files-recurse-submodules.sh was broken with GIT_TEST_SPLIT_INDEX set in 188dce131f ("ls-files: use repository object", 2017-06-22), and t7814-grep-recurse-submodules.sh was also broken in a similar manner, probably by introducing struct repository there, although I didn't track down the exact commit for that. be489d02d2 ("revision.c: --indexed-objects add objects from all worktrees", 2017-08-23) breaks with split index mode in a similar manner, not erroring out when it can't read the index, but instead carrying on with pruning, without taking the index of the worktree into account. Fix this by passing an additional gitdir parameter to read_index_from, to indicate where it should look for and read the shared index from. read_cache_from() defaults to using the gitdir of the_repository. As it is mostly a convenience macro, having to pass get_git_dir() for every call seems overkill, and if necessary users can have more control by using read_index_from(). Helped-by: Brandon Williams <bmwill@google.com> Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-01-07 22:30:13 +00:00
worktree_git_path(wt, "index"),
get_worktree_git_dir(wt)) > 0)
do_add_index_objects_to_pending(revs, &istate, flags);
discard_index(&istate);
}
free_worktrees(worktrees);
}
struct add_alternate_refs_data {
struct rev_info *revs;
unsigned int flags;
};
static void add_one_alternate_ref(const struct object_id *oid,
void *vdata)
{
const char *name = ".alternate";
struct add_alternate_refs_data *data = vdata;
struct object *obj;
obj = get_reference(data->revs, name, oid, data->flags);
add_rev_cmdline(data->revs, obj, name, REV_CMD_REV, data->flags);
add_pending_object(data->revs, obj, name);
}
static void add_alternate_refs_to_pending(struct rev_info *revs,
unsigned int flags)
{
struct add_alternate_refs_data data;
data.revs = revs;
data.flags = flags;
for_each_alternate_ref(add_one_alternate_ref, &data);
}
static int add_parents_only(struct rev_info *revs, const char *arg_, int flags,
int exclude_parent)
{
struct object_id oid;
struct object *it;
struct commit *commit;
struct commit_list *parents;
int parent_number;
revision: keep track of the end-user input from the command line Given a complex set of revision specifiers on the command line, it is too late to look at the flags of the objects in the initial traversal list at the beginning of limit_list() in order to determine what the objects the end-user explicitly listed on the command line were. The process to move objects from the pending array to the traversal list may have marked objects that are not mentioned as UNINTERESTING, when handle_commit() marked the parents of UNINTERESTING commits mentioned on the command line by calling mark_parents_uninteresting(). This made "rev-list --ancestry-path ^A ..." to mistakenly list commits that are descendants of A's parents but that are not descendants of A itself, as ^A from the command line causes A and its parents marked as UNINTERESTING before coming to limit_list(), and we try to enumerate the commits that are descendants of these commits that are UNINTERESTING before we start walking the history. It actually is too late even if we inspected the pending object array before calling prepare_revision_walk(), as some of the same objects might have been mentioned twice, once as positive and another time as negative. The "rev-list --some-option A --not --all" command may want to notice, even if the resulting set is empty, that the user showed some interest in "A" and do something special about it. Prepare a separate array to keep track of what syntactic element was used to cause each object to appear in the pending array from the command line, and populate it as setup_revisions() parses the command line. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-26 00:35:39 +00:00
const char *arg = arg_;
if (*arg == '^') {
flags ^= UNINTERESTING | BOTTOM;
arg++;
}
sha1_name: convert get_sha1* to get_oid* Now that all the callers of get_sha1 directly or indirectly use struct object_id, rename the functions starting with get_sha1 to start with get_oid. Convert the internals in sha1_name.c to use struct object_id as well, and eliminate explicit length checks where possible. Convert a use of 40 in get_oid_basic to GIT_SHA1_HEXSZ. Outside of sha1_name.c and cache.h, this transition was made with the following semantic patch: @@ expression E1, E2; @@ - get_sha1(E1, E2.hash) + get_oid(E1, &E2) @@ expression E1, E2; @@ - get_sha1(E1, E2->hash) + get_oid(E1, E2) @@ expression E1, E2; @@ - get_sha1_committish(E1, E2.hash) + get_oid_committish(E1, &E2) @@ expression E1, E2; @@ - get_sha1_committish(E1, E2->hash) + get_oid_committish(E1, E2) @@ expression E1, E2; @@ - get_sha1_treeish(E1, E2.hash) + get_oid_treeish(E1, &E2) @@ expression E1, E2; @@ - get_sha1_treeish(E1, E2->hash) + get_oid_treeish(E1, E2) @@ expression E1, E2; @@ - get_sha1_commit(E1, E2.hash) + get_oid_commit(E1, &E2) @@ expression E1, E2; @@ - get_sha1_commit(E1, E2->hash) + get_oid_commit(E1, E2) @@ expression E1, E2; @@ - get_sha1_tree(E1, E2.hash) + get_oid_tree(E1, &E2) @@ expression E1, E2; @@ - get_sha1_tree(E1, E2->hash) + get_oid_tree(E1, E2) @@ expression E1, E2; @@ - get_sha1_blob(E1, E2.hash) + get_oid_blob(E1, &E2) @@ expression E1, E2; @@ - get_sha1_blob(E1, E2->hash) + get_oid_blob(E1, E2) @@ expression E1, E2, E3, E4; @@ - get_sha1_with_context(E1, E2, E3.hash, E4) + get_oid_with_context(E1, E2, &E3, E4) @@ expression E1, E2, E3, E4; @@ - get_sha1_with_context(E1, E2, E3->hash, E4) + get_oid_with_context(E1, E2, E3, E4) Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-13 23:49:28 +00:00
if (get_oid_committish(arg, &oid))
return 0;
while (1) {
it = get_reference(revs, arg, &oid, 0);
if (!it && revs->ignore_missing)
return 0;
if (it->type != OBJ_TAG)
break;
if (!((struct tag*)it)->tagged)
return 0;
oidcpy(&oid, &((struct tag*)it)->tagged->oid);
}
if (it->type != OBJ_COMMIT)
return 0;
commit = (struct commit *)it;
if (exclude_parent &&
exclude_parent > commit_list_count(commit->parents))
return 0;
for (parents = commit->parents, parent_number = 1;
parents;
parents = parents->next, parent_number++) {
if (exclude_parent && parent_number != exclude_parent)
continue;
it = &parents->item->object;
it->flags |= flags;
revision: keep track of the end-user input from the command line Given a complex set of revision specifiers on the command line, it is too late to look at the flags of the objects in the initial traversal list at the beginning of limit_list() in order to determine what the objects the end-user explicitly listed on the command line were. The process to move objects from the pending array to the traversal list may have marked objects that are not mentioned as UNINTERESTING, when handle_commit() marked the parents of UNINTERESTING commits mentioned on the command line by calling mark_parents_uninteresting(). This made "rev-list --ancestry-path ^A ..." to mistakenly list commits that are descendants of A's parents but that are not descendants of A itself, as ^A from the command line causes A and its parents marked as UNINTERESTING before coming to limit_list(), and we try to enumerate the commits that are descendants of these commits that are UNINTERESTING before we start walking the history. It actually is too late even if we inspected the pending object array before calling prepare_revision_walk(), as some of the same objects might have been mentioned twice, once as positive and another time as negative. The "rev-list --some-option A --not --all" command may want to notice, even if the resulting set is empty, that the user showed some interest in "A" and do something special about it. Prepare a separate array to keep track of what syntactic element was used to cause each object to appear in the pending array from the command line, and populate it as setup_revisions() parses the command line. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-26 00:35:39 +00:00
add_rev_cmdline(revs, it, arg_, REV_CMD_PARENTS_ONLY, flags);
add_pending_object(revs, it, arg);
}
return 1;
}
void repo_init_revisions(struct repository *r,
struct rev_info *revs,
const char *prefix)
{
memset(revs, 0, sizeof(*revs));
revs->repo = r;
revs->abbrev = DEFAULT_ABBREV;
gitweb.cgi history not shown This does: - add a "rev.simplify_history" flag which defaults to on - it turns it off for "git whatchanged" (which thus now has real semantics outside of "git log") - it adds a command line flag ("--full-history") to turn it off for others (ie you can make "git log" and "gitk" etc get the semantics if you want to. Now, just as an example of _why_ you really really really want to simplify history by default, apply this patch, install it, and try these two command lines: gitk --full-history -- git.c gitk -- git.c and compare the output. So with this, you can also now do git whatchanged -p -- gitweb.cgi git log -p --full-history -- gitweb.cgi and it will show the old history of gitweb.cgi, even though it's not relevant to the _current_ state of the name "gitweb.cgi" NOTE NOTE NOTE! It will still actually simplify away merges that didn't change anything at all into either child. That creates these bogus strange discontinuities if you look at it with "gitk" (look at the --full-history gitk output for git.c, and you'll see a few strange cases). So the whole "--parent" thing ends up somewhat bogus with --full-history because of this, but I'm not sure it's worth even worrying about. I don't think you'd ever want to really use "--full-history" with the graphical representation, I just give it as an example exactly to show _why_ doing so would be insane. I think this is trivial enough and useful enough to be worth merging into the stable branch. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-06-11 17:57:35 +00:00
revs->simplify_history = 1;
revs->pruning.repo = r;
diff: make struct diff_flags members lowercase Now that the flags stored in struct diff_flags are being accessed directly and not through macros, change all struct members from being uppercase to lowercase. This conversion is done using the following semantic patch: @@ expression E; @@ - E.RECURSIVE + E.recursive @@ expression E; @@ - E.TREE_IN_RECURSIVE + E.tree_in_recursive @@ expression E; @@ - E.BINARY + E.binary @@ expression E; @@ - E.TEXT + E.text @@ expression E; @@ - E.FULL_INDEX + E.full_index @@ expression E; @@ - E.SILENT_ON_REMOVE + E.silent_on_remove @@ expression E; @@ - E.FIND_COPIES_HARDER + E.find_copies_harder @@ expression E; @@ - E.FOLLOW_RENAMES + E.follow_renames @@ expression E; @@ - E.RENAME_EMPTY + E.rename_empty @@ expression E; @@ - E.HAS_CHANGES + E.has_changes @@ expression E; @@ - E.QUICK + E.quick @@ expression E; @@ - E.NO_INDEX + E.no_index @@ expression E; @@ - E.ALLOW_EXTERNAL + E.allow_external @@ expression E; @@ - E.EXIT_WITH_STATUS + E.exit_with_status @@ expression E; @@ - E.REVERSE_DIFF + E.reverse_diff @@ expression E; @@ - E.CHECK_FAILED + E.check_failed @@ expression E; @@ - E.RELATIVE_NAME + E.relative_name @@ expression E; @@ - E.IGNORE_SUBMODULES + E.ignore_submodules @@ expression E; @@ - E.DIRSTAT_CUMULATIVE + E.dirstat_cumulative @@ expression E; @@ - E.DIRSTAT_BY_FILE + E.dirstat_by_file @@ expression E; @@ - E.ALLOW_TEXTCONV + E.allow_textconv @@ expression E; @@ - E.TEXTCONV_SET_VIA_CMDLINE + E.textconv_set_via_cmdline @@ expression E; @@ - E.DIFF_FROM_CONTENTS + E.diff_from_contents @@ expression E; @@ - E.DIRTY_SUBMODULES + E.dirty_submodules @@ expression E; @@ - E.IGNORE_UNTRACKED_IN_SUBMODULES + E.ignore_untracked_in_submodules @@ expression E; @@ - E.IGNORE_DIRTY_SUBMODULES + E.ignore_dirty_submodules @@ expression E; @@ - E.OVERRIDE_SUBMODULE_CONFIG + E.override_submodule_config @@ expression E; @@ - E.DIRSTAT_BY_LINE + E.dirstat_by_line @@ expression E; @@ - E.FUNCCONTEXT + E.funccontext @@ expression E; @@ - E.PICKAXE_IGNORE_CASE + E.pickaxe_ignore_case @@ expression E; @@ - E.DEFAULT_FOLLOW_RENAMES + E.default_follow_renames Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-31 18:19:11 +00:00
revs->pruning.flags.recursive = 1;
revs->pruning.flags.quick = 1;
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
revs->pruning.add_remove = file_add_remove;
revs->pruning.change = file_change;
revision: quit pruning diff more quickly when possible When the revision traversal machinery is given a pathspec, we must compute the parent-diff for each commit to determine which ones are TREESAME. We set the QUICK diff flag to avoid looking at more entries than we need; we really just care whether there are any changes at all. But there is one case where we want to know a bit more: if --remove-empty is set, we care about finding cases where the change consists only of added entries (in which case we may prune the parent in try_to_simplify_commit()). To cover that case, our file_add_remove() callback does not quit the diff upon seeing an added entry; it keeps looking for other types of entries. But this means when --remove-empty is not set (and it is not by default), we compute more of the diff than is necessary. You can see this in a pathological case where a commit adds a very large number of entries, and we limit based on a broad pathspec. E.g.: perl -e ' chomp(my $blob = `git hash-object -w --stdin </dev/null`); for my $a (1..1000) { for my $b (1..1000) { print "100644 $blob\t$a/$b\n"; } } ' | git update-index --index-info git commit -qm add git rev-list HEAD -- . This case takes about 100ms now, but after this patch only needs 6ms. That's not a huge improvement, but it's easy to get and it protects us against even more pathological cases (e.g., going from 1 million to 10 million files would take ten times as long with the current code, but not increase at all after this patch). This is reported to minorly speed-up pathspec limiting in real world repositories (like the 100-million-file Windows repository), but probably won't make a noticeable difference outside of pathological setups. This patch actually covers the case without --remove-empty, and the case where we see only deletions. See the in-code comment for details. Note that we have to add a new member to the diff_options struct so that our callback can see the value of revs->remove_empty_trees. This callback parameter could be passed to the "add_remove" and "change" callbacks, but there's not much point. They already receive the diff_options struct, and doing it this way avoids having to update the function signature of the other callbacks (arguably the format_callback and output_prefix functions could benefit from the same simplification). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-13 15:27:45 +00:00
revs->pruning.change_fn_data = revs;
toposort: rename "lifo" field The primary invariant of sort_in_topological_order() is that a parent commit is not emitted until all children of it are. When traversing a forked history like this with "git log C E": A----B----C \ D----E we ensure that A is emitted after all of B, C, D, and E are done, B has to wait until C is done, and D has to wait until E is done. In some applications, however, we would further want to control how these child commits B, C, D and E on two parallel ancestry chains are shown. Most of the time, we would want to see C and B emitted together, and then E and D, and finally A (i.e. the --topo-order output). The "lifo" parameter of the sort_in_topological_order() function is used to control this behaviour. We start the traversal by knowing two commits, C and E. While keeping in mind that we also need to inspect E later, we pick C first to inspect, and we notice and record that B needs to be inspected. By structuring the "work to be done" set as a LIFO stack, we ensure that B is inspected next, before other in-flight commits we had known that we will need to inspect, e.g. E. When showing in --date-order, we would want to see commits ordered by timestamps, i.e. show C, E, B and D in this order before showing A, possibly mixing commits from two parallel histories together. When "lifo" parameter is set to false, the function keeps the "work to be done" set sorted in the date order to realize this semantics. After inspecting C, we add B to the "work to be done" set, but the next commit we inspect from the set is E which is newer than B. The name "lifo", however, is too strongly tied to the way how the function implements its behaviour, and does not describe what the behaviour _means_. Replace this field with an enum rev_sort_order, with two possible values: REV_SORT_IN_GRAPH_ORDER and REV_SORT_BY_COMMIT_DATE, and update the existing code. The mechanical replacement rule is: "lifo == 0" is equivalent to "sort_order == REV_SORT_BY_COMMIT_DATE" "lifo == 1" is equivalent to "sort_order == REV_SORT_IN_GRAPH_ORDER" Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-06-06 23:07:14 +00:00
revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
revs->dense = 1;
revs->prefix = prefix;
revs->max_age = -1;
revs->min_age = -1;
revs->skip_count = -1;
revs->max_count = -1;
revs->max_parents = -1;
revs->expand_tabs_in_log = -1;
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
revs->commit_format = CMIT_FMT_DEFAULT;
revs->expand_tabs_in_log_default = 8;
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
built-ins: trust the "prefix" from run_builtin() Change code in "builtin/grep.c" and "builtin/ls-tree.c" to trust the "prefix" passed from "run_builtin()". The "prefix" we get from setup.c is either going to be NULL or a string of length >0, never "". So we can drop the "prefix && *prefix" checks added for "builtin/grep.c" in 0d042fecf2f (git-grep: show pathnames relative to the current directory, 2006-08-11), and for "builtin/ls-tree.c" in a69dd585fca (ls-tree: chomp leading directories when run from a subdirectory, 2005-12-23). As seen in code in revision.c that was added in cd676a51367 (diff --relative: output paths as relative to the current subdirectory, 2008-02-12) we already have existing code that does away with this assertion. This makes it easier to reason about a subsequent change to the "prefix_length" code in grep.c in a subsequent commit, and since we're going to the trouble of doing that let's leave behind an assert() to promise this to any future callers. For "builtin/grep.c" it would be painful to pass the "prefix" down the callchain of: cmd_grep -> grep_tree -> grep_submodule -> grep_cache -> grep_oid -> grep_source_name So for the code that needs it in grep_source_name() let's add a "grep_prefix" variable similar to the existing "ls_tree_prefix". While at it let's move the code in cmd_ls_tree() around so that we assign to the "ls_tree_prefix" right after declaring the variables, and stop assigning to "prefix". We only subsequently used that variable later in the function after clobbering it. Let's just use our own "grep_prefix" instead. Let's also add an assert() in git.c, so that we'll make this promise about the "prefix" to any current and future callers, as well as to any readers of the code. Code history: * The strlen() in "grep.c" hasn't been used since 493b7a08d80 (grep: accept relative paths outside current working directory, 2009-09-05). When that code was added in 0d042fecf2f (git-grep: show pathnames relative to the current directory, 2006-08-11) we used the length. But since 493b7a08d80 we haven't used it for anything except a boolean check that we could have done on the "prefix" member itself. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-02-16 00:00:34 +00:00
grep_init(&revs->grep_filter, revs->repo);
revs->grep_filter.status_only = 1;
repo_diff_setup(revs->repo, &revs->diffopt);
if (prefix && !revs->diffopt.prefix) {
diff --relative: output paths as relative to the current subdirectory This adds --relative option to the diff family. When you start from a subdirectory: $ git diff --relative shows only the diff that is inside your current subdirectory, and without $prefix part. People who usually live in subdirectories may like it. There are a few things I should also mention about the change: - This works not just with diff but also works with the log family of commands, but the history pruning is not affected. In other words, if you go to a subdirectory, you can say: $ git log --relative -p but it will show the log message even for commits that do not touch the current directory. You can limit it by giving pathspec yourself: $ git log --relative -p . This originally was not a conscious design choice, but we have a way to affect diff pathspec and pruning pathspec independently. IOW "git log --full-diff -p ." tells it to prune history to commits that affect the current subdirectory but show the changes with full context. I think it makes more sense to leave pruning independent from --relative than the obvious alternative of always pruning with the current subdirectory, which would break the symmetry. - Because this works also with the log family, you could format-patch a single change, limiting the effect to your subdirectory, like so: $ cd gitk-git $ git format-patch -1 --relative 911f1eb But because that is a special purpose usage, this option will never become the default, with or without repository or user preference configuration. The risk of producing a partial patch and sending it out by mistake is too great if we did so. - This is inherently incompatible with --no-index, which is a bolted-on hack that does not have much to do with git itself. I didn't bother checking and erroring out on the combined use of the options, but probably I should. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-12 22:26:02 +00:00
revs->diffopt.prefix = prefix;
revs->diffopt.prefix_length = strlen(prefix);
}
init_display_notes(&revs->notes_opt);
}
static void add_pending_commit_list(struct rev_info *revs,
struct commit_list *commit_list,
unsigned int flags)
{
while (commit_list) {
struct object *object = &commit_list->item->object;
object->flags |= flags;
add_pending_object(revs, object, oid_to_hex(&object->oid));
commit_list = commit_list->next;
}
}
static void prepare_show_merge(struct rev_info *revs)
{
struct commit_list *bases;
struct commit *head, *other;
struct object_id oid;
const char **prune = NULL;
int i, prune_num = 1; /* counting terminating NULL */
struct index_state *istate = revs->repo->index;
if (get_oid("HEAD", &oid))
die("--merge without HEAD?");
Convert lookup_commit* to struct object_id Convert lookup_commit, lookup_commit_or_die, lookup_commit_reference, and lookup_commit_reference_gently to take struct object_id arguments. Introduce a temporary in parse_object buffer in order to convert this function. This is required since in order to convert parse_object and parse_object_buffer, lookup_commit_reference_gently and lookup_commit_or_die would need to be converted. Not introducing a temporary would therefore require that lookup_commit_or_die take a struct object_id *, but lookup_commit would take unsigned char *, leaving a confusing and hard-to-use interface. parse_object_buffer will lose this temporary in a later patch. This commit was created with manual changes to commit.c, commit.h, and object.c, plus the following semantic patch: @@ expression E1, E2; @@ - lookup_commit_reference_gently(E1.hash, E2) + lookup_commit_reference_gently(&E1, E2) @@ expression E1, E2; @@ - lookup_commit_reference_gently(E1->hash, E2) + lookup_commit_reference_gently(E1, E2) @@ expression E1; @@ - lookup_commit_reference(E1.hash) + lookup_commit_reference(&E1) @@ expression E1; @@ - lookup_commit_reference(E1->hash) + lookup_commit_reference(E1) @@ expression E1; @@ - lookup_commit(E1.hash) + lookup_commit(&E1) @@ expression E1; @@ - lookup_commit(E1->hash) + lookup_commit(E1) @@ expression E1, E2; @@ - lookup_commit_or_die(E1.hash, E2) + lookup_commit_or_die(&E1, E2) @@ expression E1, E2; @@ - lookup_commit_or_die(E1->hash, E2) + lookup_commit_or_die(E1, E2) Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-06 22:10:10 +00:00
head = lookup_commit_or_die(&oid, "HEAD");
if (get_oid("MERGE_HEAD", &oid))
die("--merge without MERGE_HEAD?");
Convert lookup_commit* to struct object_id Convert lookup_commit, lookup_commit_or_die, lookup_commit_reference, and lookup_commit_reference_gently to take struct object_id arguments. Introduce a temporary in parse_object buffer in order to convert this function. This is required since in order to convert parse_object and parse_object_buffer, lookup_commit_reference_gently and lookup_commit_or_die would need to be converted. Not introducing a temporary would therefore require that lookup_commit_or_die take a struct object_id *, but lookup_commit would take unsigned char *, leaving a confusing and hard-to-use interface. parse_object_buffer will lose this temporary in a later patch. This commit was created with manual changes to commit.c, commit.h, and object.c, plus the following semantic patch: @@ expression E1, E2; @@ - lookup_commit_reference_gently(E1.hash, E2) + lookup_commit_reference_gently(&E1, E2) @@ expression E1, E2; @@ - lookup_commit_reference_gently(E1->hash, E2) + lookup_commit_reference_gently(E1, E2) @@ expression E1; @@ - lookup_commit_reference(E1.hash) + lookup_commit_reference(&E1) @@ expression E1; @@ - lookup_commit_reference(E1->hash) + lookup_commit_reference(E1) @@ expression E1; @@ - lookup_commit(E1.hash) + lookup_commit(&E1) @@ expression E1; @@ - lookup_commit(E1->hash) + lookup_commit(E1) @@ expression E1, E2; @@ - lookup_commit_or_die(E1.hash, E2) + lookup_commit_or_die(&E1, E2) @@ expression E1, E2; @@ - lookup_commit_or_die(E1->hash, E2) + lookup_commit_or_die(E1, E2) Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-06 22:10:10 +00:00
other = lookup_commit_or_die(&oid, "MERGE_HEAD");
add_pending_object(revs, &head->object, "HEAD");
add_pending_object(revs, &other->object, "MERGE_HEAD");
bases = get_merge_bases(head, other);
add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING | BOTTOM);
add_pending_commit_list(revs, bases, UNINTERESTING | BOTTOM);
free_commit_list(bases);
head->object.flags |= SYMMETRIC_LEFT;
if (!istate->cache_nr)
repo_read_index(revs->repo);
for (i = 0; i < istate->cache_nr; i++) {
const struct cache_entry *ce = istate->cache[i];
if (!ce_stage(ce))
continue;
if (ce_path_match(istate, ce, &revs->prune_data, NULL)) {
prune_num++;
REALLOC_ARRAY(prune, prune_num);
prune[prune_num-2] = ce->name;
prune[prune_num-1] = NULL;
}
while ((i+1 < istate->cache_nr) &&
ce_same_name(ce, istate->cache[i+1]))
i++;
}
clear_pathspec(&revs->prune_data);
parse_pathspec(&revs->prune_data, PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
PATHSPEC_PREFER_FULL | PATHSPEC_LITERAL_PATH, "", prune);
revs->limited = 1;
}
static int dotdot_missing(const char *arg, char *dotdot,
struct rev_info *revs, int symmetric)
{
if (revs->ignore_missing)
return 0;
/* de-munge so we report the full argument */
*dotdot = '.';
die(symmetric
? "Invalid symmetric difference expression %s"
: "Invalid revision range %s", arg);
}
static int handle_dotdot_1(const char *arg, char *dotdot,
struct rev_info *revs, int flags,
int cant_be_filename,
struct object_context *a_oc,
struct object_context *b_oc)
{
const char *a_name, *b_name;
struct object_id a_oid, b_oid;
struct object *a_obj, *b_obj;
unsigned int a_flags, b_flags;
int symmetric = 0;
unsigned int flags_exclude = flags ^ (UNINTERESTING | BOTTOM);
unsigned int oc_flags = GET_OID_COMMITTISH | GET_OID_RECORD_PATH;
a_name = arg;
if (!*a_name)
a_name = "HEAD";
b_name = dotdot + 2;
if (*b_name == '.') {
symmetric = 1;
b_name++;
}
if (!*b_name)
b_name = "HEAD";
if (get_oid_with_context(revs->repo, a_name, oc_flags, &a_oid, a_oc) ||
get_oid_with_context(revs->repo, b_name, oc_flags, &b_oid, b_oc))
return -1;
if (!cant_be_filename) {
*dotdot = '.';
verify_non_filename(revs->prefix, arg);
*dotdot = '\0';
}
a_obj = parse_object(revs->repo, &a_oid);
b_obj = parse_object(revs->repo, &b_oid);
if (!a_obj || !b_obj)
return dotdot_missing(arg, dotdot, revs, symmetric);
if (!symmetric) {
/* just A..B */
b_flags = flags;
a_flags = flags_exclude;
} else {
/* A...B -- find merge bases between the two */
struct commit *a, *b;
struct commit_list *exclude;
a = lookup_commit_reference(revs->repo, &a_obj->oid);
b = lookup_commit_reference(revs->repo, &b_obj->oid);
if (!a || !b)
return dotdot_missing(arg, dotdot, revs, symmetric);
exclude = get_merge_bases(a, b);
add_rev_cmdline_list(revs, exclude, REV_CMD_MERGE_BASE,
flags_exclude);
add_pending_commit_list(revs, exclude, flags_exclude);
free_commit_list(exclude);
b_flags = flags;
a_flags = flags | SYMMETRIC_LEFT;
}
a_obj->flags |= a_flags;
b_obj->flags |= b_flags;
add_rev_cmdline(revs, a_obj, a_name, REV_CMD_LEFT, a_flags);
add_rev_cmdline(revs, b_obj, b_name, REV_CMD_RIGHT, b_flags);
add_pending_object_with_path(revs, a_obj, a_name, a_oc->mode, a_oc->path);
add_pending_object_with_path(revs, b_obj, b_name, b_oc->mode, b_oc->path);
return 0;
}
static int handle_dotdot(const char *arg,
struct rev_info *revs, int flags,
int cant_be_filename)
{
struct object_context a_oc, b_oc;
char *dotdot = strstr(arg, "..");
int ret;
if (!dotdot)
return -1;
memset(&a_oc, 0, sizeof(a_oc));
memset(&b_oc, 0, sizeof(b_oc));
*dotdot = '\0';
ret = handle_dotdot_1(arg, dotdot, revs, flags, cant_be_filename,
&a_oc, &b_oc);
*dotdot = '.';
free(a_oc.path);
free(b_oc.path);
return ret;
}
revision: set rev_input_given in handle_revision_arg() Commit 7ba826290a (revision: add rev_input_given flag, 2017-08-02) added a flag to rev_info to tell whether we got any revision arguments. As explained there, this is necessary because some revision arguments may not produce any pending traversal objects, but should still inhibit default behaviors (e.g., a glob that matches nothing). However, it only set the flag in the globbing code, but not for revisions we get on the command-line or via stdin. This leads to two problems: - the command-line code keeps its own separate got_rev_arg flag; this isn't wrong, but it's confusing and an extra maintenance burden - even specifically-named rev arguments might end up not adding any pending objects: if --ignore-missing is set, then specifying a missing object is a noop rather than an error. And that leads to some user-visible bugs: - when deciding whether a default rev like "HEAD" should kick in, we check both got_rev_arg and rev_input_given. That means that "--ignore-missing $ZERO_OID" works on the command-line (where we set got_rev_arg) but not on --stdin (where we don't) - when rev-list decides whether it should complain that it wasn't given a starting point, it relies on rev_input_given. So it can't even get the command-line "--ignore-missing $ZERO_OID" right Let's consistently set the flag if we got any revision argument. That lets us clean up the redundant got_rev_arg, and fixes both of those bugs (but note there are three new tests: we'll confirm the already working git-log command-line case). A few implementation notes: - conceptually we want to set the flag whenever handle_revision_arg() finds an actual revision arg ("handles" it, you might say). But it covers a ton of cases with early returns. Rather than annotating each one, we just wrap it and use its success exit-code to set the flag in one spot. - the new rev-list test is in t6018, which is titled to cover globs. This isn't exactly a glob, but it made sense to stick it with the other tests that handle the "even though we got a rev, we have no pending objects" case, which are globs. - the tests check for the oid of a missing object, which it's pretty clear --ignore-missing should ignore. You can see the same behavior with "--ignore-missing a-ref-that-does-not-exist", because --ignore-missing treats them both the same. That's perhaps less clearly correct, and we may want to change that in the future. But the way the code and tests here are written, we'd continue to do the right thing even if it does. Reported-by: Bryan Turner <bturner@atlassian.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-26 20:13:05 +00:00
static int handle_revision_arg_1(const char *arg_, struct rev_info *revs, int flags, unsigned revarg_opt)
{
struct object_context oc;
char *mark;
struct object *object;
struct object_id oid;
int local_flags;
revision: keep track of the end-user input from the command line Given a complex set of revision specifiers on the command line, it is too late to look at the flags of the objects in the initial traversal list at the beginning of limit_list() in order to determine what the objects the end-user explicitly listed on the command line were. The process to move objects from the pending array to the traversal list may have marked objects that are not mentioned as UNINTERESTING, when handle_commit() marked the parents of UNINTERESTING commits mentioned on the command line by calling mark_parents_uninteresting(). This made "rev-list --ancestry-path ^A ..." to mistakenly list commits that are descendants of A's parents but that are not descendants of A itself, as ^A from the command line causes A and its parents marked as UNINTERESTING before coming to limit_list(), and we try to enumerate the commits that are descendants of these commits that are UNINTERESTING before we start walking the history. It actually is too late even if we inspected the pending object array before calling prepare_revision_walk(), as some of the same objects might have been mentioned twice, once as positive and another time as negative. The "rev-list --some-option A --not --all" command may want to notice, even if the resulting set is empty, that the user showed some interest in "A" and do something special about it. Prepare a separate array to keep track of what syntactic element was used to cause each object to appear in the pending array from the command line, and populate it as setup_revisions() parses the command line. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-26 00:35:39 +00:00
const char *arg = arg_;
int cant_be_filename = revarg_opt & REVARG_CANNOT_BE_FILENAME;
unsigned get_sha1_flags = GET_OID_RECORD_PATH;
flags = flags & UNINTERESTING ? flags | BOTTOM : flags & ~BOTTOM;
if (!cant_be_filename && !strcmp(arg, "..")) {
/*
* Just ".."? That is not a range but the
* pathspec for the parent directory.
*/
return -1;
}
if (!handle_dotdot(arg, revs, flags, revarg_opt))
return 0;
mark = strstr(arg, "^@");
if (mark && !mark[2]) {
*mark = 0;
if (add_parents_only(revs, arg, flags, 0))
return 0;
*mark = '^';
}
mark = strstr(arg, "^!");
if (mark && !mark[2]) {
*mark = 0;
if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), 0))
*mark = '^';
}
mark = strstr(arg, "^-");
if (mark) {
int exclude_parent = 1;
if (mark[2]) {
char *end;
exclude_parent = strtoul(mark + 2, &end, 10);
if (*end != '\0' || !exclude_parent)
return -1;
}
*mark = 0;
if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), exclude_parent))
*mark = '^';
}
local_flags = 0;
if (*arg == '^') {
local_flags = UNINTERESTING | BOTTOM;
arg++;
}
if (revarg_opt & REVARG_COMMITTISH)
get_sha1_flags |= GET_OID_COMMITTISH;
if (get_oid_with_context(revs->repo, arg, get_sha1_flags, &oid, &oc))
return revs->ignore_missing ? 0 : -1;
if (!cant_be_filename)
verify_non_filename(revs->prefix, arg);
object = get_reference(revs, arg, &oid, flags ^ local_flags);
if (!object)
return revs->ignore_missing ? 0 : -1;
revision: keep track of the end-user input from the command line Given a complex set of revision specifiers on the command line, it is too late to look at the flags of the objects in the initial traversal list at the beginning of limit_list() in order to determine what the objects the end-user explicitly listed on the command line were. The process to move objects from the pending array to the traversal list may have marked objects that are not mentioned as UNINTERESTING, when handle_commit() marked the parents of UNINTERESTING commits mentioned on the command line by calling mark_parents_uninteresting(). This made "rev-list --ancestry-path ^A ..." to mistakenly list commits that are descendants of A's parents but that are not descendants of A itself, as ^A from the command line causes A and its parents marked as UNINTERESTING before coming to limit_list(), and we try to enumerate the commits that are descendants of these commits that are UNINTERESTING before we start walking the history. It actually is too late even if we inspected the pending object array before calling prepare_revision_walk(), as some of the same objects might have been mentioned twice, once as positive and another time as negative. The "rev-list --some-option A --not --all" command may want to notice, even if the resulting set is empty, that the user showed some interest in "A" and do something special about it. Prepare a separate array to keep track of what syntactic element was used to cause each object to appear in the pending array from the command line, and populate it as setup_revisions() parses the command line. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-26 00:35:39 +00:00
add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
add_pending_object_with_path(revs, object, arg, oc.mode, oc.path);
free(oc.path);
return 0;
}
revision: set rev_input_given in handle_revision_arg() Commit 7ba826290a (revision: add rev_input_given flag, 2017-08-02) added a flag to rev_info to tell whether we got any revision arguments. As explained there, this is necessary because some revision arguments may not produce any pending traversal objects, but should still inhibit default behaviors (e.g., a glob that matches nothing). However, it only set the flag in the globbing code, but not for revisions we get on the command-line or via stdin. This leads to two problems: - the command-line code keeps its own separate got_rev_arg flag; this isn't wrong, but it's confusing and an extra maintenance burden - even specifically-named rev arguments might end up not adding any pending objects: if --ignore-missing is set, then specifying a missing object is a noop rather than an error. And that leads to some user-visible bugs: - when deciding whether a default rev like "HEAD" should kick in, we check both got_rev_arg and rev_input_given. That means that "--ignore-missing $ZERO_OID" works on the command-line (where we set got_rev_arg) but not on --stdin (where we don't) - when rev-list decides whether it should complain that it wasn't given a starting point, it relies on rev_input_given. So it can't even get the command-line "--ignore-missing $ZERO_OID" right Let's consistently set the flag if we got any revision argument. That lets us clean up the redundant got_rev_arg, and fixes both of those bugs (but note there are three new tests: we'll confirm the already working git-log command-line case). A few implementation notes: - conceptually we want to set the flag whenever handle_revision_arg() finds an actual revision arg ("handles" it, you might say). But it covers a ton of cases with early returns. Rather than annotating each one, we just wrap it and use its success exit-code to set the flag in one spot. - the new rev-list test is in t6018, which is titled to cover globs. This isn't exactly a glob, but it made sense to stick it with the other tests that handle the "even though we got a rev, we have no pending objects" case, which are globs. - the tests check for the oid of a missing object, which it's pretty clear --ignore-missing should ignore. You can see the same behavior with "--ignore-missing a-ref-that-does-not-exist", because --ignore-missing treats them both the same. That's perhaps less clearly correct, and we may want to change that in the future. But the way the code and tests here are written, we'd continue to do the right thing even if it does. Reported-by: Bryan Turner <bturner@atlassian.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-26 20:13:05 +00:00
int handle_revision_arg(const char *arg, struct rev_info *revs, int flags, unsigned revarg_opt)
{
int ret = handle_revision_arg_1(arg, revs, flags, revarg_opt);
if (!ret)
revs->rev_input_given = 1;
return ret;
}
static void read_pathspec_from_stdin(struct strbuf *sb,
struct strvec *prune)
{
while (strbuf_getline(sb, stdin) != EOF)
strvec_push(prune, sb->buf);
}
static void read_revisions_from_stdin(struct rev_info *revs,
struct strvec *prune)
{
struct strbuf sb;
int seen_dashdash = 0;
int save_warning;
save_warning = warn_on_object_refname_ambiguity;
warn_on_object_refname_ambiguity = 0;
strbuf_init(&sb, 1000);
while (strbuf_getline(&sb, stdin) != EOF) {
int len = sb.len;
if (!len)
break;
if (sb.buf[0] == '-') {
if (len == 2 && sb.buf[1] == '-') {
seen_dashdash = 1;
break;
}
die("options not supported in --stdin mode");
}
object_array_entry: fix memory handling of the name field Previously, the memory management of the object_array_entry::name field was inconsistent and undocumented. object_array_entries are ultimately created by a single function, add_object_array_with_mode(), which has an argument "const char *name". This function used to simply set the name field to reference the string pointed to by the name parameter, and nobody on the object_array side ever freed the memory. Thus, it assumed that the memory for the name field would be managed by the caller, and that the lifetime of that string would be at least as long as the lifetime of the object_array_entry. But callers were inconsistent: * Some passed pointers to constant strings or argv entries, which was OK. * Some passed pointers to newly-allocated memory, but didn't arrange for the memory ever to be freed. * Some passed the return value of sha1_to_hex(), which is a pointer to a statically-allocated buffer that can be overwritten at any time. * Some passed pointers to refnames that they received from a for_each_ref()-type iteration, but the lifetimes of such refnames is not guaranteed by the refs API. Bring consistency to this mess by changing object_array to make its own copy for the object_array_entry::name field and free this memory when an object_array_entry is deleted from the array. Many callers were passing the empty string as the name parameter, so as a performance optimization, treat the empty string specially. Instead of making a copy, store a pointer to a statically-allocated empty string to object_array_entry::name. When deleting such an entry, skip the free(). Change the callers that were already passing copies to add_object_array_with_mode() to either skip the copy, or (if the memory needed to be allocated anyway) freeing the memory itself. A part of this commit effectively reverts 70d26c6e76 read_revisions_from_stdin: make copies for handle_revision_arg because the copying introduced by that commit (which is still necessary) is now done at a deeper level. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-25 09:08:14 +00:00
if (handle_revision_arg(sb.buf, revs, 0,
REVARG_CANNOT_BE_FILENAME))
die("bad revision '%s'", sb.buf);
}
if (seen_dashdash)
read_pathspec_from_stdin(&sb, prune);
strbuf_release(&sb);
warn_on_object_refname_ambiguity = save_warning;
}
static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
{
append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
}
log --author/--committer: really match only with name part When we tried to find commits done by AUTHOR, the first implementation tried to pattern match a line with "^author .*AUTHOR", which later was enhanced to strip leading caret and look for "^author AUTHOR" when the search pattern was anchored at the left end (i.e. --author="^AUTHOR"). This had a few problems: * When looking for fixed strings (e.g. "git log -F --author=x --grep=y"), the regexp internally used "^author .*x" would never match anything; * To match at the end (e.g. "git log --author='google.com>$'"), the generated regexp has to also match the trailing timestamp part the commit header lines have. Also, in order to determine if the '$' at the end means "match at the end of the line" or just a literal dollar sign (probably backslash-quoted), we would need to parse the regexp ourselves. An earlier alternative tried to make sure that a line matches "^author " (to limit by field name) and the user supplied pattern at the same time. While it solved the -F problem by introducing a special override for matching the "^author ", it did not solve the trailing timestamp nor tail match problem. It also would have matched every commit if --author=author was asked for, not because the author's email part had this string, but because every commit header line that talks about the author begins with that field name, regardleses of who wrote it. Instead of piling more hacks on top of hacks, this rethinks the grep machinery that is used to look for strings in the commit header, and makes sure that (1) field name matches literally at the beginning of the line, followed by a SP, and (2) the user supplied pattern is matched against the remainder of the line, excluding the trailing timestamp data. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-09-05 05:15:02 +00:00
static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
{
log --author/--committer: really match only with name part When we tried to find commits done by AUTHOR, the first implementation tried to pattern match a line with "^author .*AUTHOR", which later was enhanced to strip leading caret and look for "^author AUTHOR" when the search pattern was anchored at the left end (i.e. --author="^AUTHOR"). This had a few problems: * When looking for fixed strings (e.g. "git log -F --author=x --grep=y"), the regexp internally used "^author .*x" would never match anything; * To match at the end (e.g. "git log --author='google.com>$'"), the generated regexp has to also match the trailing timestamp part the commit header lines have. Also, in order to determine if the '$' at the end means "match at the end of the line" or just a literal dollar sign (probably backslash-quoted), we would need to parse the regexp ourselves. An earlier alternative tried to make sure that a line matches "^author " (to limit by field name) and the user supplied pattern at the same time. While it solved the -F problem by introducing a special override for matching the "^author ", it did not solve the trailing timestamp nor tail match problem. It also would have matched every commit if --author=author was asked for, not because the author's email part had this string, but because every commit header line that talks about the author begins with that field name, regardleses of who wrote it. Instead of piling more hacks on top of hacks, this rethinks the grep machinery that is used to look for strings in the commit header, and makes sure that (1) field name matches literally at the beginning of the line, followed by a SP, and (2) the user supplied pattern is matched against the remainder of the line, excluding the trailing timestamp data. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-09-05 05:15:02 +00:00
append_header_grep_pattern(&revs->grep_filter, field, pattern);
}
static void add_message_grep(struct rev_info *revs, const char *pattern)
{
add_grep(revs, pattern, GREP_PATTERN_BODY);
}
static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
int *unkc, const char **unkv,
const struct setup_revision_opt* opt)
{
const char *arg = argv[0];
const char *optarg;
int argcount;
const unsigned hexsz = the_hash_algo->hexsz;
/* pseudo revision arguments */
if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
!strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
!strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
!strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
!strcmp(arg, "--bisect") || starts_with(arg, "--glob=") ||
!strcmp(arg, "--indexed-objects") ||
!strcmp(arg, "--alternate-refs") ||
starts_with(arg, "--exclude=") ||
starts_with(arg, "--branches=") || starts_with(arg, "--tags=") ||
starts_with(arg, "--remotes=") || starts_with(arg, "--no-walk="))
{
unkv[(*unkc)++] = arg;
return 1;
}
if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
revs->max_count = atoi(optarg);
revs->no_walk = 0;
return argcount;
} else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
revs->skip_count = atoi(optarg);
return argcount;
} else if ((*arg == '-') && isdigit(arg[1])) {
/* accept -<digit>, like traditional "head" */
if (strtol_i(arg + 1, 10, &revs->max_count) < 0 ||
revs->max_count < 0)
die("'%s': not a non-negative integer", arg + 1);
revs->no_walk = 0;
} else if (!strcmp(arg, "-n")) {
if (argc <= 1)
return error("-n requires an argument");
revs->max_count = atoi(argv[1]);
revs->no_walk = 0;
return 2;
} else if (skip_prefix(arg, "-n", &optarg)) {
revs->max_count = atoi(optarg);
revs->no_walk = 0;
} else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
revs->max_age = atoi(optarg);
return argcount;
} else if ((argcount = parse_long_opt("since", argv, &optarg))) {
revs->max_age = approxidate(optarg);
return argcount;
} else if ((argcount = parse_long_opt("after", argv, &optarg))) {
revs->max_age = approxidate(optarg);
return argcount;
} else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
revs->min_age = atoi(optarg);
return argcount;
} else if ((argcount = parse_long_opt("before", argv, &optarg))) {
revs->min_age = approxidate(optarg);
return argcount;
} else if ((argcount = parse_long_opt("until", argv, &optarg))) {
revs->min_age = approxidate(optarg);
return argcount;
} else if (!strcmp(arg, "--first-parent")) {
revs->first_parent_only = 1;
} else if (!strcmp(arg, "--exclude-first-parent-only")) {
revs->exclude_first_parent_only = 1;
} else if (!strcmp(arg, "--ancestry-path")) {
revs->ancestry_path = 1;
revs->simplify_history = 0;
revs->limited = 1;
} else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
init_reflog_walk(&revs->reflog_info);
} else if (!strcmp(arg, "--default")) {
if (argc <= 1)
return error("bad --default argument");
revs->def = argv[1];
return 2;
} else if (!strcmp(arg, "--merge")) {
revs->show_merge = 1;
} else if (!strcmp(arg, "--topo-order")) {
toposort: rename "lifo" field The primary invariant of sort_in_topological_order() is that a parent commit is not emitted until all children of it are. When traversing a forked history like this with "git log C E": A----B----C \ D----E we ensure that A is emitted after all of B, C, D, and E are done, B has to wait until C is done, and D has to wait until E is done. In some applications, however, we would further want to control how these child commits B, C, D and E on two parallel ancestry chains are shown. Most of the time, we would want to see C and B emitted together, and then E and D, and finally A (i.e. the --topo-order output). The "lifo" parameter of the sort_in_topological_order() function is used to control this behaviour. We start the traversal by knowing two commits, C and E. While keeping in mind that we also need to inspect E later, we pick C first to inspect, and we notice and record that B needs to be inspected. By structuring the "work to be done" set as a LIFO stack, we ensure that B is inspected next, before other in-flight commits we had known that we will need to inspect, e.g. E. When showing in --date-order, we would want to see commits ordered by timestamps, i.e. show C, E, B and D in this order before showing A, possibly mixing commits from two parallel histories together. When "lifo" parameter is set to false, the function keeps the "work to be done" set sorted in the date order to realize this semantics. After inspecting C, we add B to the "work to be done" set, but the next commit we inspect from the set is E which is newer than B. The name "lifo", however, is too strongly tied to the way how the function implements its behaviour, and does not describe what the behaviour _means_. Replace this field with an enum rev_sort_order, with two possible values: REV_SORT_IN_GRAPH_ORDER and REV_SORT_BY_COMMIT_DATE, and update the existing code. The mechanical replacement rule is: "lifo == 0" is equivalent to "sort_order == REV_SORT_BY_COMMIT_DATE" "lifo == 1" is equivalent to "sort_order == REV_SORT_IN_GRAPH_ORDER" Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-06-06 23:07:14 +00:00
revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
revs->topo_order = 1;
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
} else if (!strcmp(arg, "--simplify-merges")) {
revs->simplify_merges = 1;
revs->topo_order = 1;
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
revs->rewrite_parents = 1;
revs->simplify_history = 0;
revs->limited = 1;
} else if (!strcmp(arg, "--simplify-by-decoration")) {
revs->simplify_merges = 1;
revs->topo_order = 1;
revs->rewrite_parents = 1;
revs->simplify_history = 0;
revs->simplify_by_decoration = 1;
revs->limited = 1;
revs->prune = 1;
} else if (!strcmp(arg, "--date-order")) {
toposort: rename "lifo" field The primary invariant of sort_in_topological_order() is that a parent commit is not emitted until all children of it are. When traversing a forked history like this with "git log C E": A----B----C \ D----E we ensure that A is emitted after all of B, C, D, and E are done, B has to wait until C is done, and D has to wait until E is done. In some applications, however, we would further want to control how these child commits B, C, D and E on two parallel ancestry chains are shown. Most of the time, we would want to see C and B emitted together, and then E and D, and finally A (i.e. the --topo-order output). The "lifo" parameter of the sort_in_topological_order() function is used to control this behaviour. We start the traversal by knowing two commits, C and E. While keeping in mind that we also need to inspect E later, we pick C first to inspect, and we notice and record that B needs to be inspected. By structuring the "work to be done" set as a LIFO stack, we ensure that B is inspected next, before other in-flight commits we had known that we will need to inspect, e.g. E. When showing in --date-order, we would want to see commits ordered by timestamps, i.e. show C, E, B and D in this order before showing A, possibly mixing commits from two parallel histories together. When "lifo" parameter is set to false, the function keeps the "work to be done" set sorted in the date order to realize this semantics. After inspecting C, we add B to the "work to be done" set, but the next commit we inspect from the set is E which is newer than B. The name "lifo", however, is too strongly tied to the way how the function implements its behaviour, and does not describe what the behaviour _means_. Replace this field with an enum rev_sort_order, with two possible values: REV_SORT_IN_GRAPH_ORDER and REV_SORT_BY_COMMIT_DATE, and update the existing code. The mechanical replacement rule is: "lifo == 0" is equivalent to "sort_order == REV_SORT_BY_COMMIT_DATE" "lifo == 1" is equivalent to "sort_order == REV_SORT_IN_GRAPH_ORDER" Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-06-06 23:07:14 +00:00
revs->sort_order = REV_SORT_BY_COMMIT_DATE;
revs->topo_order = 1;
} else if (!strcmp(arg, "--author-date-order")) {
revs->sort_order = REV_SORT_BY_AUTHOR_DATE;
revs->topo_order = 1;
} else if (!strcmp(arg, "--early-output")) {
revs->early_output = 100;
revs->topo_order = 1;
} else if (skip_prefix(arg, "--early-output=", &optarg)) {
if (strtoul_ui(optarg, 10, &revs->early_output) < 0)
die("'%s': not a non-negative integer", optarg);
revs->topo_order = 1;
} else if (!strcmp(arg, "--parents")) {
revs->rewrite_parents = 1;
revs->print_parents = 1;
} else if (!strcmp(arg, "--dense")) {
revs->dense = 1;
} else if (!strcmp(arg, "--sparse")) {
revs->dense = 0;
} else if (!strcmp(arg, "--in-commit-order")) {
revs->tree_blobs_in_commit_order = 1;
} else if (!strcmp(arg, "--remove-empty")) {
revs->remove_empty_trees = 1;
} else if (!strcmp(arg, "--merges")) {
revs->min_parents = 2;
} else if (!strcmp(arg, "--no-merges")) {
revs->max_parents = 1;
} else if (skip_prefix(arg, "--min-parents=", &optarg)) {
revs->min_parents = atoi(optarg);
} else if (!strcmp(arg, "--no-min-parents")) {
revs->min_parents = 0;
} else if (skip_prefix(arg, "--max-parents=", &optarg)) {
revs->max_parents = atoi(optarg);
} else if (!strcmp(arg, "--no-max-parents")) {
revs->max_parents = -1;
} else if (!strcmp(arg, "--boundary")) {
revs->boundary = 1;
} else if (!strcmp(arg, "--left-right")) {
revs->left_right = 1;
} else if (!strcmp(arg, "--left-only")) {
if (revs->right_only)
die("--left-only is incompatible with --right-only"
" or --cherry");
revs->left_only = 1;
} else if (!strcmp(arg, "--right-only")) {
if (revs->left_only)
die(_("options '%s' and '%s' cannot be used together"), "--right-only", "--left-only");
revs->right_only = 1;
} else if (!strcmp(arg, "--cherry")) {
if (revs->left_only)
die(_("options '%s' and '%s' cannot be used together"), "--cherry", "--left-only");
revs->cherry_mark = 1;
revs->right_only = 1;
revs->max_parents = 1;
revs->limited = 1;
} else if (!strcmp(arg, "--count")) {
revs->count = 1;
} else if (!strcmp(arg, "--cherry-mark")) {
if (revs->cherry_pick)
die(_("options '%s' and '%s' cannot be used together"), "--cherry-mark", "--cherry-pick");
revs->cherry_mark = 1;
revs->limited = 1; /* needs limit_list() */
} else if (!strcmp(arg, "--cherry-pick")) {
if (revs->cherry_mark)
die(_("options '%s' and '%s' cannot be used together"), "--cherry-pick", "--cherry-mark");
revs->cherry_pick = 1;
revs->limited = 1;
} else if (!strcmp(arg, "--objects")) {
revs->tag_objects = 1;
revs->tree_objects = 1;
revs->blob_objects = 1;
} else if (!strcmp(arg, "--objects-edge")) {
revs->tag_objects = 1;
revs->tree_objects = 1;
revs->blob_objects = 1;
revs->edge_hint = 1;
} else if (!strcmp(arg, "--objects-edge-aggressive")) {
revs->tag_objects = 1;
revs->tree_objects = 1;
revs->blob_objects = 1;
revs->edge_hint = 1;
revs->edge_hint_aggressive = 1;
} else if (!strcmp(arg, "--verify-objects")) {
revs->tag_objects = 1;
revs->tree_objects = 1;
revs->blob_objects = 1;
revs->verify_objects = 1;
} else if (!strcmp(arg, "--unpacked")) {
revs->unpacked = 1;
} else if (starts_with(arg, "--unpacked=")) {
die(_("--unpacked=<packfile> no longer supported"));
revision: learn '--no-kept-objects' A future caller will want to be able to perform a reachability traversal which terminates when visiting an object found in a kept pack. The closest existing option is '--honor-pack-keep', but this isn't quite what we want. Instead of halting the traversal midway through, a full traversal is always performed, and the results are only trimmed afterwords. Besides needing to introduce a new flag (since culling results post-facto can be different than halting the traversal as it's happening), there is an additional wrinkle handling the distinction in-core and on-disk kept packs. That is: what kinds of kept pack should stop the traversal? Introduce '--no-kept-objects[=<on-disk|in-core>]' to specify which kinds of kept packs, if any, should stop a traversal. This can be useful for callers that want to perform a reachability analysis, but want to leave certain packs alone (for e.g., when doing a geometric repack that has some "large" packs which are kept in-core that it wants to leave alone). Note that this option is not guaranteed to produce exactly the set of objects that aren't in kept packs, since it's possible the traversal order may end up in a situation where a non-kept ancestor was "cut off" by a kept object (at which point we would stop traversing). But, we don't care about absolute correctness here, since this will eventually be used as a purely additive guide in an upcoming new repack mode. Explicitly avoid documenting this new flag, since it is only used internally. In theory we could avoid even adding it rev-list, but being able to spell this option out on the command-line makes some special cases easier to test without promising to keep it behaving consistently forever. Those tricky cases are exercised in t6114. Signed-off-by: Taylor Blau <me@ttaylorr.com> Reviewed-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-23 02:25:07 +00:00
} else if (!strcmp(arg, "--no-kept-objects")) {
revs->no_kept_objects = 1;
revs->keep_pack_cache_flags |= IN_CORE_KEEP_PACKS;
revs->keep_pack_cache_flags |= ON_DISK_KEEP_PACKS;
} else if (skip_prefix(arg, "--no-kept-objects=", &optarg)) {
revs->no_kept_objects = 1;
if (!strcmp(optarg, "in-core"))
revs->keep_pack_cache_flags |= IN_CORE_KEEP_PACKS;
if (!strcmp(optarg, "on-disk"))
revs->keep_pack_cache_flags |= ON_DISK_KEEP_PACKS;
} else if (!strcmp(arg, "-r")) {
revs->diff = 1;
diff: make struct diff_flags members lowercase Now that the flags stored in struct diff_flags are being accessed directly and not through macros, change all struct members from being uppercase to lowercase. This conversion is done using the following semantic patch: @@ expression E; @@ - E.RECURSIVE + E.recursive @@ expression E; @@ - E.TREE_IN_RECURSIVE + E.tree_in_recursive @@ expression E; @@ - E.BINARY + E.binary @@ expression E; @@ - E.TEXT + E.text @@ expression E; @@ - E.FULL_INDEX + E.full_index @@ expression E; @@ - E.SILENT_ON_REMOVE + E.silent_on_remove @@ expression E; @@ - E.FIND_COPIES_HARDER + E.find_copies_harder @@ expression E; @@ - E.FOLLOW_RENAMES + E.follow_renames @@ expression E; @@ - E.RENAME_EMPTY + E.rename_empty @@ expression E; @@ - E.HAS_CHANGES + E.has_changes @@ expression E; @@ - E.QUICK + E.quick @@ expression E; @@ - E.NO_INDEX + E.no_index @@ expression E; @@ - E.ALLOW_EXTERNAL + E.allow_external @@ expression E; @@ - E.EXIT_WITH_STATUS + E.exit_with_status @@ expression E; @@ - E.REVERSE_DIFF + E.reverse_diff @@ expression E; @@ - E.CHECK_FAILED + E.check_failed @@ expression E; @@ - E.RELATIVE_NAME + E.relative_name @@ expression E; @@ - E.IGNORE_SUBMODULES + E.ignore_submodules @@ expression E; @@ - E.DIRSTAT_CUMULATIVE + E.dirstat_cumulative @@ expression E; @@ - E.DIRSTAT_BY_FILE + E.dirstat_by_file @@ expression E; @@ - E.ALLOW_TEXTCONV + E.allow_textconv @@ expression E; @@ - E.TEXTCONV_SET_VIA_CMDLINE + E.textconv_set_via_cmdline @@ expression E; @@ - E.DIFF_FROM_CONTENTS + E.diff_from_contents @@ expression E; @@ - E.DIRTY_SUBMODULES + E.dirty_submodules @@ expression E; @@ - E.IGNORE_UNTRACKED_IN_SUBMODULES + E.ignore_untracked_in_submodules @@ expression E; @@ - E.IGNORE_DIRTY_SUBMODULES + E.ignore_dirty_submodules @@ expression E; @@ - E.OVERRIDE_SUBMODULE_CONFIG + E.override_submodule_config @@ expression E; @@ - E.DIRSTAT_BY_LINE + E.dirstat_by_line @@ expression E; @@ - E.FUNCCONTEXT + E.funccontext @@ expression E; @@ - E.PICKAXE_IGNORE_CASE + E.pickaxe_ignore_case @@ expression E; @@ - E.DEFAULT_FOLLOW_RENAMES + E.default_follow_renames Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-31 18:19:11 +00:00
revs->diffopt.flags.recursive = 1;
} else if (!strcmp(arg, "-t")) {
revs->diff = 1;
diff: make struct diff_flags members lowercase Now that the flags stored in struct diff_flags are being accessed directly and not through macros, change all struct members from being uppercase to lowercase. This conversion is done using the following semantic patch: @@ expression E; @@ - E.RECURSIVE + E.recursive @@ expression E; @@ - E.TREE_IN_RECURSIVE + E.tree_in_recursive @@ expression E; @@ - E.BINARY + E.binary @@ expression E; @@ - E.TEXT + E.text @@ expression E; @@ - E.FULL_INDEX + E.full_index @@ expression E; @@ - E.SILENT_ON_REMOVE + E.silent_on_remove @@ expression E; @@ - E.FIND_COPIES_HARDER + E.find_copies_harder @@ expression E; @@ - E.FOLLOW_RENAMES + E.follow_renames @@ expression E; @@ - E.RENAME_EMPTY + E.rename_empty @@ expression E; @@ - E.HAS_CHANGES + E.has_changes @@ expression E; @@ - E.QUICK + E.quick @@ expression E; @@ - E.NO_INDEX + E.no_index @@ expression E; @@ - E.ALLOW_EXTERNAL + E.allow_external @@ expression E; @@ - E.EXIT_WITH_STATUS + E.exit_with_status @@ expression E; @@ - E.REVERSE_DIFF + E.reverse_diff @@ expression E; @@ - E.CHECK_FAILED + E.check_failed @@ expression E; @@ - E.RELATIVE_NAME + E.relative_name @@ expression E; @@ - E.IGNORE_SUBMODULES + E.ignore_submodules @@ expression E; @@ - E.DIRSTAT_CUMULATIVE + E.dirstat_cumulative @@ expression E; @@ - E.DIRSTAT_BY_FILE + E.dirstat_by_file @@ expression E; @@ - E.ALLOW_TEXTCONV + E.allow_textconv @@ expression E; @@ - E.TEXTCONV_SET_VIA_CMDLINE + E.textconv_set_via_cmdline @@ expression E; @@ - E.DIFF_FROM_CONTENTS + E.diff_from_contents @@ expression E; @@ - E.DIRTY_SUBMODULES + E.dirty_submodules @@ expression E; @@ - E.IGNORE_UNTRACKED_IN_SUBMODULES + E.ignore_untracked_in_submodules @@ expression E; @@ - E.IGNORE_DIRTY_SUBMODULES + E.ignore_dirty_submodules @@ expression E; @@ - E.OVERRIDE_SUBMODULE_CONFIG + E.override_submodule_config @@ expression E; @@ - E.DIRSTAT_BY_LINE + E.dirstat_by_line @@ expression E; @@ - E.FUNCCONTEXT + E.funccontext @@ expression E; @@ - E.PICKAXE_IGNORE_CASE + E.pickaxe_ignore_case @@ expression E; @@ - E.DEFAULT_FOLLOW_RENAMES + E.default_follow_renames Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-31 18:19:11 +00:00
revs->diffopt.flags.recursive = 1;
revs->diffopt.flags.tree_in_recursive = 1;
} else if ((argcount = diff_merges_parse_opts(revs, argv))) {
return argcount;
} else if (!strcmp(arg, "-v")) {
revs->verbose_header = 1;
} else if (!strcmp(arg, "--pretty")) {
revs->verbose_header = 1;
revs->pretty_given = 1;
get_commit_format(NULL, revs);
} else if (skip_prefix(arg, "--pretty=", &optarg) ||
skip_prefix(arg, "--format=", &optarg)) {
/*
* Detached form ("--pretty X" as opposed to "--pretty=X")
* not allowed, since the argument is optional.
*/
revs->verbose_header = 1;
revs->pretty_given = 1;
get_commit_format(optarg, revs);
} else if (!strcmp(arg, "--expand-tabs")) {
revs->expand_tabs_in_log = 8;
} else if (!strcmp(arg, "--no-expand-tabs")) {
revs->expand_tabs_in_log = 0;
} else if (skip_prefix(arg, "--expand-tabs=", &arg)) {
int val;
if (strtol_i(arg, 10, &val) < 0 || val < 0)
die("'%s': not a non-negative integer", arg);
revs->expand_tabs_in_log = val;
} else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
notes: break set_display_notes() into smaller functions In 8164c961e1 (format-patch: use --notes behavior for format.notes, 2019-12-09), we introduced set_display_notes() which was a monolithic function with three mutually exclusive branches. Break the function up into three small and simple functions that each are only responsible for one task. This family of functions accepts an `int *show_notes` instead of returning a value suitable for assignment to `show_notes`. This is for two reasons. First of all, this guarantees that the external `show_notes` variable changes in lockstep with the `struct display_notes_opt`. Second, this prompts future developers to be careful about doing something meaningful with this value. In fact, a NULL check is intentionally omitted because causing a segfault here would tell the future developer that they are meant to use the value for something meaningful. One alternative was making the family of functions accept a `struct rev_info *` instead of the `struct display_notes_opt *`, since the former contains the `show_notes` field as well. This does not work because we have to call git_config() before repo_init_revisions(). However, if we had a `struct rev_info`, we'd need to initialize it before it gets assigned values from git_config(). As a result, we break the circular dependency by having standalone `int show_notes` and `struct display_notes_opt notes_opt` variables which temporarily hold values from git_config() until the values are copied over to `rev`. To implement this change, we need to get a pointer to `rev_info::show_notes`. Unfortunately, this is not possible with bitfields and only direct-assignment is possible. Change `rev_info::show_notes` to a non-bitfield int so that we can get its address. Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-12 00:49:50 +00:00
enable_default_display_notes(&revs->notes_opt, &revs->show_notes);
revs->show_notes_given = 1;
} else if (!strcmp(arg, "--show-signature")) {
revs->show_signature = 1;
} else if (!strcmp(arg, "--no-show-signature")) {
revs->show_signature = 0;
} else if (!strcmp(arg, "--show-linear-break")) {
revs->break_bar = " ..........";
revs->track_linear = 1;
revs->track_first_time = 1;
} else if (skip_prefix(arg, "--show-linear-break=", &optarg)) {
revs->break_bar = xstrdup(optarg);
revs->track_linear = 1;
revs->track_first_time = 1;
} else if (skip_prefix(arg, "--show-notes=", &optarg) ||
skip_prefix(arg, "--notes=", &optarg)) {
if (starts_with(arg, "--show-notes=") &&
revs->notes_opt.use_default_notes < 0)
revs->notes_opt.use_default_notes = 1;
notes: break set_display_notes() into smaller functions In 8164c961e1 (format-patch: use --notes behavior for format.notes, 2019-12-09), we introduced set_display_notes() which was a monolithic function with three mutually exclusive branches. Break the function up into three small and simple functions that each are only responsible for one task. This family of functions accepts an `int *show_notes` instead of returning a value suitable for assignment to `show_notes`. This is for two reasons. First of all, this guarantees that the external `show_notes` variable changes in lockstep with the `struct display_notes_opt`. Second, this prompts future developers to be careful about doing something meaningful with this value. In fact, a NULL check is intentionally omitted because causing a segfault here would tell the future developer that they are meant to use the value for something meaningful. One alternative was making the family of functions accept a `struct rev_info *` instead of the `struct display_notes_opt *`, since the former contains the `show_notes` field as well. This does not work because we have to call git_config() before repo_init_revisions(). However, if we had a `struct rev_info`, we'd need to initialize it before it gets assigned values from git_config(). As a result, we break the circular dependency by having standalone `int show_notes` and `struct display_notes_opt notes_opt` variables which temporarily hold values from git_config() until the values are copied over to `rev`. To implement this change, we need to get a pointer to `rev_info::show_notes`. Unfortunately, this is not possible with bitfields and only direct-assignment is possible. Change `rev_info::show_notes` to a non-bitfield int so that we can get its address. Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-12 00:49:50 +00:00
enable_ref_display_notes(&revs->notes_opt, &revs->show_notes, optarg);
revs->show_notes_given = 1;
} else if (!strcmp(arg, "--no-notes")) {
notes: break set_display_notes() into smaller functions In 8164c961e1 (format-patch: use --notes behavior for format.notes, 2019-12-09), we introduced set_display_notes() which was a monolithic function with three mutually exclusive branches. Break the function up into three small and simple functions that each are only responsible for one task. This family of functions accepts an `int *show_notes` instead of returning a value suitable for assignment to `show_notes`. This is for two reasons. First of all, this guarantees that the external `show_notes` variable changes in lockstep with the `struct display_notes_opt`. Second, this prompts future developers to be careful about doing something meaningful with this value. In fact, a NULL check is intentionally omitted because causing a segfault here would tell the future developer that they are meant to use the value for something meaningful. One alternative was making the family of functions accept a `struct rev_info *` instead of the `struct display_notes_opt *`, since the former contains the `show_notes` field as well. This does not work because we have to call git_config() before repo_init_revisions(). However, if we had a `struct rev_info`, we'd need to initialize it before it gets assigned values from git_config(). As a result, we break the circular dependency by having standalone `int show_notes` and `struct display_notes_opt notes_opt` variables which temporarily hold values from git_config() until the values are copied over to `rev`. To implement this change, we need to get a pointer to `rev_info::show_notes`. Unfortunately, this is not possible with bitfields and only direct-assignment is possible. Change `rev_info::show_notes` to a non-bitfield int so that we can get its address. Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-12 00:49:50 +00:00
disable_display_notes(&revs->notes_opt, &revs->show_notes);
revs->show_notes_given = 1;
} else if (!strcmp(arg, "--standard-notes")) {
revs->show_notes_given = 1;
revs->notes_opt.use_default_notes = 1;
} else if (!strcmp(arg, "--no-standard-notes")) {
revs->notes_opt.use_default_notes = 0;
} else if (!strcmp(arg, "--oneline")) {
revs->verbose_header = 1;
get_commit_format("oneline", revs);
revs->pretty_given = 1;
revs->abbrev_commit = 1;
} else if (!strcmp(arg, "--graph")) {
graph_clear(revs->graph);
revs->graph = graph_init(revs);
} else if (!strcmp(arg, "--no-graph")) {
graph_clear(revs->graph);
revs->graph = NULL;
} else if (!strcmp(arg, "--encode-email-headers")) {
revs->encode_email_headers = 1;
} else if (!strcmp(arg, "--no-encode-email-headers")) {
revs->encode_email_headers = 0;
} else if (!strcmp(arg, "--root")) {
revs->show_root_diff = 1;
} else if (!strcmp(arg, "--no-commit-id")) {
revs->no_commit_id = 1;
} else if (!strcmp(arg, "--always")) {
revs->always_show_header = 1;
} else if (!strcmp(arg, "--no-abbrev")) {
revs->abbrev = 0;
} else if (!strcmp(arg, "--abbrev")) {
revs->abbrev = DEFAULT_ABBREV;
} else if (skip_prefix(arg, "--abbrev=", &optarg)) {
revs->abbrev = strtoul(optarg, NULL, 10);
if (revs->abbrev < MINIMUM_ABBREV)
revs->abbrev = MINIMUM_ABBREV;
else if (revs->abbrev > hexsz)
revs->abbrev = hexsz;
} else if (!strcmp(arg, "--abbrev-commit")) {
revs->abbrev_commit = 1;
revs->abbrev_commit_given = 1;
} else if (!strcmp(arg, "--no-abbrev-commit")) {
revs->abbrev_commit = 0;
} else if (!strcmp(arg, "--full-diff")) {
revs->diff = 1;
revs->full_diff = 1;
revision: --show-pulls adds helpful merges The default file history simplification of "git log -- <path>" or "git rev-list -- <path>" focuses on providing the smallest set of commits that first contributed a change. The revision walk greatly restricts the set of walked commits by visiting only the first TREESAME parent of a merge commit, when one exists. This means that portions of the commit-graph are not walked, which can be a performance benefit, but can also "hide" commits that added changes but were ignored by a merge resolution. The --full-history option modifies this by walking all commits and reporting a merge commit as "interesting" if it has _any_ parent that is not TREESAME. This tends to be an over-representation of important commits, especially in an environment where most merge commits are created by pull request completion. Suppose we have a commit A and we create a commit B on top that changes our file. When we merge the pull request, we create a merge commit M. If no one else changed the file in the first-parent history between M and A, then M will not be TREESAME to its first parent, but will be TREESAME to B. Thus, the simplified history will be "B". However, M will appear in the --full-history mode. However, suppose that a number of topics T1, T2, ..., Tn were created based on commits C1, C2, ..., Cn between A and M as follows: A----C1----C2--- ... ---Cn----M------P1---P2--- ... ---Pn \ \ \ \ / / / / \ \__.. \ \/ ..__T1 / Tn \ \__.. /\ ..__T2 / \_____________________B \____________________/ If the commits T1, T2, ... Tn did not change the file, then all of P1 through Pn will be TREESAME to their first parent, but not TREESAME to their second. This means that all of those merge commits appear in the --full-history view, with edges that immediately collapse into the lower history without introducing interesting single-parent commits. The --simplify-merges option was introduced to remove these extra merge commits. By noticing that the rewritten parents are reachable from their first parents, those edges can be simplified away. Finally, the commits now look like single-parent commits that are TREESAME to their "only" parent. Thus, they are removed and this issue does not cause issues anymore. However, this also ends up removing the commit M from the history view! Even worse, the --simplify-merges option requires walking the entire history before returning a single result. Many Git users are using Git alongside a Git service that provides code storage alongside a code review tool commonly called "Pull Requests" or "Merge Requests" against a target branch. When these requests are accepted and merged, they typically create a merge commit whose first parent is the previous branch tip and the second parent is the tip of the topic branch used for the request. This presents a valuable order to the parents, but also makes that merge commit slightly special. Users may want to see not only which commits changed a file, but which pull requests merged those commits into their branch. In the previous example, this would mean the users want to see the merge commit "M" in addition to the single- parent commit "C". Users are even more likely to want these merge commits when they use pull requests to merge into a feature branch before merging that feature branch into their trunk. In some sense, users are asking for the "first" merge commit to bring in the change to their branch. As long as the parent order is consistent, this can be handled with the following rule: Include a merge commit if it is not TREESAME to its first parent, but is TREESAME to a later parent. These merges look like the merge commits that would result from running "git pull <topic>" on a main branch. Thus, the option to show these commits is called "--show-pulls". This has the added benefit of showing the commits created by closing a pull request or merge request on any of the Git hosting and code review platforms. To test these options, extend the standard test example to include a merge commit that is not TREESAME to its first parent. It is surprising that that option was not already in the example, as it is instructive. In particular, this extension demonstrates a common issue with file history simplification. When a user resolves a merge conflict using "-Xours" or otherwise ignoring one side of the conflict, they create a TREESAME edge that probably should not be TREESAME. This leads users to become frustrated and complain that "my change disappeared!" In my experience, showing them history with --full-history and --simplify-merges quickly reveals the problematic merge. As mentioned, this option is expensive to compute. The --show-pulls option _might_ show the merge commit (usually titled "resolving conflicts") more quickly. Of course, this depends on the user having the correct parent order, which is backwards when using "git pull master" from a topic branch. There are some special considerations when combining the --show-pulls option with --simplify-merges. This requires adding a new PULL_MERGE object flag to store the information from the initial TREESAME comparisons. This helps avoid dropping those commits in later filters. This is covered by a test, including how the parents can be simplified. Since "struct object" has already ruined its 32-bit alignment by using 33 bits across parsed, type, and flags member, let's not make it worse. PULL_MERGE is used in revision.c with the same value (1u<<15) as REACHABLE in commit-graph.c. The REACHABLE flag is only used when writing a commit-graph file, and a revision walk using --show-pulls does not happen in the same process. Care must be taken in the future to ensure this remains the case. Update Documentation/rev-list-options.txt with significant details around this option. This requires updating the example in the History Simplification section to demonstrate some of the problems with TREESAME second parents. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-10 12:19:43 +00:00
} else if (!strcmp(arg, "--show-pulls")) {
revs->show_pulls = 1;
} else if (!strcmp(arg, "--full-history")) {
revs->simplify_history = 0;
} else if (!strcmp(arg, "--relative-date")) {
convert "enum date_mode" into a struct In preparation for adding date modes that may carry extra information beyond the mode itself, this patch converts the date_mode enum into a struct. Most of the conversion is fairly straightforward; we pass the struct as a pointer and dereference the type field where necessary. Locations that declare a date_mode can use a "{}" constructor. However, the tricky case is where we use the enum labels as constants, like: show_date(t, tz, DATE_NORMAL); Ideally we could say: show_date(t, tz, &{ DATE_NORMAL }); but of course C does not allow that. Likewise, we cannot cast the constant to a struct, because we need to pass an actual address. Our options are basically: 1. Manually add a "struct date_mode d = { DATE_NORMAL }" definition to each caller, and pass "&d". This makes the callers uglier, because they sometimes do not even have their own scope (e.g., they are inside a switch statement). 2. Provide a pre-made global "date_normal" struct that can be passed by address. We'd also need "date_rfc2822", "date_iso8601", and so forth. But at least the ugliness is defined in one place. 3. Provide a wrapper that generates the correct struct on the fly. The big downside is that we end up pointing to a single global, which makes our wrapper non-reentrant. But show_date is already not reentrant, so it does not matter. This patch implements 3, along with a minor macro to keep the size of the callers sane. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-25 16:55:02 +00:00
revs->date_mode.type = DATE_RELATIVE;
revs->date_mode_explicit = 1;
} else if ((argcount = parse_long_opt("date", argv, &optarg))) {
convert "enum date_mode" into a struct In preparation for adding date modes that may carry extra information beyond the mode itself, this patch converts the date_mode enum into a struct. Most of the conversion is fairly straightforward; we pass the struct as a pointer and dereference the type field where necessary. Locations that declare a date_mode can use a "{}" constructor. However, the tricky case is where we use the enum labels as constants, like: show_date(t, tz, DATE_NORMAL); Ideally we could say: show_date(t, tz, &{ DATE_NORMAL }); but of course C does not allow that. Likewise, we cannot cast the constant to a struct, because we need to pass an actual address. Our options are basically: 1. Manually add a "struct date_mode d = { DATE_NORMAL }" definition to each caller, and pass "&d". This makes the callers uglier, because they sometimes do not even have their own scope (e.g., they are inside a switch statement). 2. Provide a pre-made global "date_normal" struct that can be passed by address. We'd also need "date_rfc2822", "date_iso8601", and so forth. But at least the ugliness is defined in one place. 3. Provide a wrapper that generates the correct struct on the fly. The big downside is that we end up pointing to a single global, which makes our wrapper non-reentrant. But show_date is already not reentrant, so it does not matter. This patch implements 3, along with a minor macro to keep the size of the callers sane. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-25 16:55:02 +00:00
parse_date_format(optarg, &revs->date_mode);
revs->date_mode_explicit = 1;
return argcount;
} else if (!strcmp(arg, "--log-size")) {
revs->show_log_size = 1;
}
/*
* Grepping the commit log
*/
else if ((argcount = parse_long_opt("author", argv, &optarg))) {
add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
return argcount;
} else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
return argcount;
} else if ((argcount = parse_long_opt("grep-reflog", argv, &optarg))) {
add_header_grep(revs, GREP_HEADER_REFLOG, optarg);
return argcount;
} else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
add_message_grep(revs, optarg);
return argcount;
} else if (!strcmp(arg, "--basic-regexp")) {
revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_BRE;
} else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_ERE;
} else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
revs->grep_filter.ignore_case = 1;
revs->diffopt.pickaxe_opts |= DIFF_PICKAXE_IGNORE_CASE;
} else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_FIXED;
} else if (!strcmp(arg, "--perl-regexp") || !strcmp(arg, "-P")) {
revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_PCRE;
} else if (!strcmp(arg, "--all-match")) {
revs->grep_filter.all_match = 1;
} else if (!strcmp(arg, "--invert-grep")) {
revs->grep_filter.no_body_match = 1;
} else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
if (strcmp(optarg, "none"))
git_log_output_encoding = xstrdup(optarg);
else
git_log_output_encoding = "";
return argcount;
} else if (!strcmp(arg, "--reverse")) {
revs->reverse ^= 1;
} else if (!strcmp(arg, "--children")) {
revs->children.name = "children";
revs->limited = 1;
} else if (!strcmp(arg, "--ignore-missing")) {
revs->ignore_missing = 1;
} else if (opt && opt->allow_exclude_promisor_objects &&
!strcmp(arg, "--exclude-promisor-objects")) {
if (fetch_if_missing)
BUG("exclude_promisor_objects can only be used when fetch_if_missing is 0");
revs->exclude_promisor_objects = 1;
} else {
int opts = diff_opt_parse(&revs->diffopt, argv, argc, revs->prefix);
if (!opts)
unkv[(*unkc)++] = arg;
return opts;
}
return 1;
}
void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
const struct option *options,
const char * const usagestr[])
{
int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
&ctx->cpidx, ctx->out, NULL);
if (n <= 0) {
error("unknown option `%s'", ctx->argv[0]);
usage_with_options(usagestr, options);
}
ctx->argv += n;
ctx->argc -= n;
}
void revision_opts_finish(struct rev_info *revs)
{
if (revs->graph && revs->track_linear)
die(_("options '%s' and '%s' cannot be used together"), "--show-linear-break", "--graph");
if (revs->graph) {
revs->topo_order = 1;
revs->rewrite_parents = 1;
}
}
static int for_each_bisect_ref(struct ref_store *refs, each_ref_fn fn,
void *cb_data, const char *term)
{
struct strbuf bisect_refs = STRBUF_INIT;
int status;
strbuf_addf(&bisect_refs, "refs/bisect/%s", term);
status = refs_for_each_fullref_in(refs, bisect_refs.buf, fn, cb_data);
strbuf_release(&bisect_refs);
return status;
}
static int for_each_bad_bisect_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
{
return for_each_bisect_ref(refs, fn, cb_data, term_bad);
}
static int for_each_good_bisect_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
{
return for_each_bisect_ref(refs, fn, cb_data, term_good);
}
static int handle_revision_pseudo_opt(struct rev_info *revs,
const char **argv, int *flags)
{
const char *arg = argv[0];
const char *optarg;
struct ref_store *refs;
int argcount;
if (revs->repo != the_repository) {
/*
* We need some something like get_submodule_worktrees()
* before we can go through all worktrees of a submodule,
* .e.g with adding all HEADs from --all, which is not
* supported right now, so stick to single worktree.
*/
if (!revs->single_worktree)
BUG("--single-worktree cannot be used together with submodule");
}
refs = get_main_ref_store(revs->repo);
/*
* NOTE!
*
* Commands like "git shortlog" will not accept the options below
* unless parse_revision_opt queues them (as opposed to erroring
* out).
*
* When implementing your new pseudo-option, remember to
* register it in the list at the top of handle_revision_opt.
*/
if (!strcmp(arg, "--all")) {
handle_refs(refs, revs, *flags, refs_for_each_ref);
handle_refs(refs, revs, *flags, refs_head_ref);
if (!revs->single_worktree) {
struct all_refs_cb cb;
init_all_refs_cb(&cb, revs, *flags);
other_head_refs(handle_one_ref, &cb);
}
clear_ref_exclusion(&revs->ref_excludes);
} else if (!strcmp(arg, "--branches")) {
handle_refs(refs, revs, *flags, refs_for_each_branch_ref);
clear_ref_exclusion(&revs->ref_excludes);
} else if (!strcmp(arg, "--bisect")) {
read_bisect_terms(&term_bad, &term_good);
handle_refs(refs, revs, *flags, for_each_bad_bisect_ref);
handle_refs(refs, revs, *flags ^ (UNINTERESTING | BOTTOM),
for_each_good_bisect_ref);
revs->bisect = 1;
} else if (!strcmp(arg, "--tags")) {
handle_refs(refs, revs, *flags, refs_for_each_tag_ref);
clear_ref_exclusion(&revs->ref_excludes);
} else if (!strcmp(arg, "--remotes")) {
handle_refs(refs, revs, *flags, refs_for_each_remote_ref);
clear_ref_exclusion(&revs->ref_excludes);
} else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
struct all_refs_cb cb;
init_all_refs_cb(&cb, revs, *flags);
for_each_glob_ref(handle_one_ref, optarg, &cb);
clear_ref_exclusion(&revs->ref_excludes);
return argcount;
} else if ((argcount = parse_long_opt("exclude", argv, &optarg))) {
add_ref_exclusion(&revs->ref_excludes, optarg);
return argcount;
} else if (skip_prefix(arg, "--branches=", &optarg)) {
struct all_refs_cb cb;
init_all_refs_cb(&cb, revs, *flags);
for_each_glob_ref_in(handle_one_ref, optarg, "refs/heads/", &cb);
clear_ref_exclusion(&revs->ref_excludes);
} else if (skip_prefix(arg, "--tags=", &optarg)) {
struct all_refs_cb cb;
init_all_refs_cb(&cb, revs, *flags);
for_each_glob_ref_in(handle_one_ref, optarg, "refs/tags/", &cb);
clear_ref_exclusion(&revs->ref_excludes);
} else if (skip_prefix(arg, "--remotes=", &optarg)) {
struct all_refs_cb cb;
init_all_refs_cb(&cb, revs, *flags);
for_each_glob_ref_in(handle_one_ref, optarg, "refs/remotes/", &cb);
clear_ref_exclusion(&revs->ref_excludes);
} else if (!strcmp(arg, "--reflog")) {
add_reflogs_to_pending(revs, *flags);
} else if (!strcmp(arg, "--indexed-objects")) {
add_index_objects_to_pending(revs, *flags);
} else if (!strcmp(arg, "--alternate-refs")) {
add_alternate_refs_to_pending(revs, *flags);
} else if (!strcmp(arg, "--not")) {
*flags ^= UNINTERESTING | BOTTOM;
} else if (!strcmp(arg, "--no-walk")) {
revs->no_walk = 1;
} else if (skip_prefix(arg, "--no-walk=", &optarg)) {
/*
* Detached form ("--no-walk X" as opposed to "--no-walk=X")
* not allowed, since the argument is optional.
*/
revs->no_walk = 1;
if (!strcmp(optarg, "sorted"))
revs->unsorted_input = 0;
else if (!strcmp(optarg, "unsorted"))
revs->unsorted_input = 1;
else
return error("invalid argument to --no-walk");
} else if (!strcmp(arg, "--do-walk")) {
revs->no_walk = 0;
} else if (!strcmp(arg, "--single-worktree")) {
revs->single_worktree = 1;
} else {
return 0;
}
return 1;
}
static void NORETURN diagnose_missing_default(const char *def)
{
int flags;
const char *refname;
refname = resolve_ref_unsafe(def, 0, NULL, &flags);
if (!refname || !(flags & REF_ISSYMREF) || (flags & REF_ISBROKEN))
die(_("your current branch appears to be broken"));
skip_prefix(refname, "refs/heads/", &refname);
die(_("your current branch '%s' does not have any commits yet"),
refname);
}
/*
* Parse revision information, filling in the "rev_info" structure,
* and removing the used arguments from the argument list.
*
* Returns the number of arguments left that weren't recognized
* (which are also moved to the head of the argument list)
*/
int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
{
revision: set rev_input_given in handle_revision_arg() Commit 7ba826290a (revision: add rev_input_given flag, 2017-08-02) added a flag to rev_info to tell whether we got any revision arguments. As explained there, this is necessary because some revision arguments may not produce any pending traversal objects, but should still inhibit default behaviors (e.g., a glob that matches nothing). However, it only set the flag in the globbing code, but not for revisions we get on the command-line or via stdin. This leads to two problems: - the command-line code keeps its own separate got_rev_arg flag; this isn't wrong, but it's confusing and an extra maintenance burden - even specifically-named rev arguments might end up not adding any pending objects: if --ignore-missing is set, then specifying a missing object is a noop rather than an error. And that leads to some user-visible bugs: - when deciding whether a default rev like "HEAD" should kick in, we check both got_rev_arg and rev_input_given. That means that "--ignore-missing $ZERO_OID" works on the command-line (where we set got_rev_arg) but not on --stdin (where we don't) - when rev-list decides whether it should complain that it wasn't given a starting point, it relies on rev_input_given. So it can't even get the command-line "--ignore-missing $ZERO_OID" right Let's consistently set the flag if we got any revision argument. That lets us clean up the redundant got_rev_arg, and fixes both of those bugs (but note there are three new tests: we'll confirm the already working git-log command-line case). A few implementation notes: - conceptually we want to set the flag whenever handle_revision_arg() finds an actual revision arg ("handles" it, you might say). But it covers a ton of cases with early returns. Rather than annotating each one, we just wrap it and use its success exit-code to set the flag in one spot. - the new rev-list test is in t6018, which is titled to cover globs. This isn't exactly a glob, but it made sense to stick it with the other tests that handle the "even though we got a rev, we have no pending objects" case, which are globs. - the tests check for the oid of a missing object, which it's pretty clear --ignore-missing should ignore. You can see the same behavior with "--ignore-missing a-ref-that-does-not-exist", because --ignore-missing treats them both the same. That's perhaps less clearly correct, and we may want to change that in the future. But the way the code and tests here are written, we'd continue to do the right thing even if it does. Reported-by: Bryan Turner <bturner@atlassian.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-26 20:13:05 +00:00
int i, flags, left, seen_dashdash, revarg_opt;
struct strvec prune_data = STRVEC_INIT;
revision: allow --end-of-options to end option parsing There's currently no robust way to tell Git that a particular option is meant to be a revision, and not an option. So if you have a branch "refs/heads/--foo", you cannot just say: git rev-list --foo You can say: git rev-list refs/heads/--foo But that breaks down if you don't know the refname, and in particular if you're a script passing along a value from elsewhere. In most programs, you can use "--" to end option parsing, like this: some-prog -- "$revision" But that doesn't work for the revision parser, because "--" is already meaningful there: it separates revisions from pathspecs. So we need some other marker to separate options from revisions. This patch introduces "--end-of-options", which serves that purpose: git rev-list --oneline --end-of-options "$revision" will work regardless of what's in "$revision" (well, if you say "--" it may fail, but it won't do something dangerous, like triggering an unexpected option). The name is verbose, but that's probably a good thing; this is meant to be used for scripted invocations where readability is more important than terseness. One alternative would be to introduce an explicit option to mark a revision, like: git rev-list --oneline --revision="$revision" That's slightly _more_ informative than this commit (because it makes even something silly like "--" unambiguous). But the pattern of using a separator like "--" is well established in git and in other commands, and it makes some scripting tasks simpler like: git rev-list --end-of-options "$@" There's no documentation in this patch, because it will make sense to describe the feature once it is available everywhere (and support will be added in further patches). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-06 14:39:58 +00:00
int seen_end_of_options = 0;
/* First, search for "--" */
if (opt && opt->assume_dashdash) {
seen_dashdash = 1;
} else {
seen_dashdash = 0;
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
if (strcmp(arg, "--"))
continue;
argv[i] = NULL;
argc = i;
if (argv[i + 1])
strvec_pushv(&prune_data, argv + i + 1);
seen_dashdash = 1;
break;
}
}
/* Second, deal with arguments and options */
flags = 0;
revarg_opt = opt ? opt->revarg_opt : 0;
if (seen_dashdash)
revarg_opt |= REVARG_CANNOT_BE_FILENAME;
for (left = i = 1; i < argc; i++) {
const char *arg = argv[i];
revision: allow --end-of-options to end option parsing There's currently no robust way to tell Git that a particular option is meant to be a revision, and not an option. So if you have a branch "refs/heads/--foo", you cannot just say: git rev-list --foo You can say: git rev-list refs/heads/--foo But that breaks down if you don't know the refname, and in particular if you're a script passing along a value from elsewhere. In most programs, you can use "--" to end option parsing, like this: some-prog -- "$revision" But that doesn't work for the revision parser, because "--" is already meaningful there: it separates revisions from pathspecs. So we need some other marker to separate options from revisions. This patch introduces "--end-of-options", which serves that purpose: git rev-list --oneline --end-of-options "$revision" will work regardless of what's in "$revision" (well, if you say "--" it may fail, but it won't do something dangerous, like triggering an unexpected option). The name is verbose, but that's probably a good thing; this is meant to be used for scripted invocations where readability is more important than terseness. One alternative would be to introduce an explicit option to mark a revision, like: git rev-list --oneline --revision="$revision" That's slightly _more_ informative than this commit (because it makes even something silly like "--" unambiguous). But the pattern of using a separator like "--" is well established in git and in other commands, and it makes some scripting tasks simpler like: git rev-list --end-of-options "$@" There's no documentation in this patch, because it will make sense to describe the feature once it is available everywhere (and support will be added in further patches). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-06 14:39:58 +00:00
if (!seen_end_of_options && *arg == '-') {
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
int opts;
opts = handle_revision_pseudo_opt(
revs, argv + i,
&flags);
if (opts > 0) {
i += opts - 1;
continue;
}
if (!strcmp(arg, "--stdin")) {
if (revs->disable_stdin) {
argv[left++] = arg;
continue;
}
rev-list: make empty --stdin not an error When we originally did the series that contains 7ba826290a (revision: add rev_input_given flag, 2017-08-02) the intent was that "git rev-list --stdin </dev/null" would similarly become a successful noop. However, an attempt at the time to do that did not work[1]. The problem is that rev_input_given serves two roles: - it tells rev-list.c that it should not error out - it tells revision.c that it should not have the "default" ref kick (e.g., "HEAD" in "git log") We want to trigger the former, but not the latter. This is technically possible with a single flag, if we set the flag only after revision.c's revs->def check. But this introduces a rather subtle ordering dependency. Instead, let's keep two flags: one to denote when we got actual input (which triggers both roles) and one for when we read stdin (which triggers only the first). This does mean a caller interested in the first role has to check both flags, but there's only one such caller. And any future callers might want to make the distinction anyway (e.g., if they care less about erroring out, and more about whether revision.c soaked up our stdin). In fact, we already keep such a flag internally in revision.c for this purpose, so this is really just exposing that to the caller (and the old function-local flag can go away in favor of our new one). [1] https://public-inbox.org/git/20170802223416.gwiezhbuxbdmbjzx@sigill.intra.peff.net/ Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-22 21:37:23 +00:00
if (revs->read_from_stdin++)
die("--stdin given twice?");
read_revisions_from_stdin(revs, &prune_data);
continue;
}
revision: allow --end-of-options to end option parsing There's currently no robust way to tell Git that a particular option is meant to be a revision, and not an option. So if you have a branch "refs/heads/--foo", you cannot just say: git rev-list --foo You can say: git rev-list refs/heads/--foo But that breaks down if you don't know the refname, and in particular if you're a script passing along a value from elsewhere. In most programs, you can use "--" to end option parsing, like this: some-prog -- "$revision" But that doesn't work for the revision parser, because "--" is already meaningful there: it separates revisions from pathspecs. So we need some other marker to separate options from revisions. This patch introduces "--end-of-options", which serves that purpose: git rev-list --oneline --end-of-options "$revision" will work regardless of what's in "$revision" (well, if you say "--" it may fail, but it won't do something dangerous, like triggering an unexpected option). The name is verbose, but that's probably a good thing; this is meant to be used for scripted invocations where readability is more important than terseness. One alternative would be to introduce an explicit option to mark a revision, like: git rev-list --oneline --revision="$revision" That's slightly _more_ informative than this commit (because it makes even something silly like "--" unambiguous). But the pattern of using a separator like "--" is well established in git and in other commands, and it makes some scripting tasks simpler like: git rev-list --end-of-options "$@" There's no documentation in this patch, because it will make sense to describe the feature once it is available everywhere (and support will be added in further patches). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-06 14:39:58 +00:00
if (!strcmp(arg, "--end-of-options")) {
seen_end_of_options = 1;
continue;
}
opts = handle_revision_opt(revs, argc - i, argv + i,
&left, argv, opt);
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
if (opts > 0) {
i += opts - 1;
continue;
}
if (opts < 0)
exit(128);
continue;
}
if (handle_revision_arg(arg, revs, flags, revarg_opt)) {
int j;
if (seen_dashdash || *arg == '^')
die("bad revision '%s'", arg);
/* If we didn't have a "--":
* (1) all filenames must exist;
* (2) all rev-args must not be interpretable
* as a valid filename.
* but the latter we have checked in the main loop.
*/
for (j = i; j < argc; j++)
verify_filename(revs->prefix, argv[j], j == i);
strvec_pushv(&prune_data, argv + i);
break;
}
}
revision_opts_finish(revs);
if (prune_data.nr) {
/*
* If we need to introduce the magic "a lone ':' means no
* pathspec whatsoever", here is the place to do so.
*
* if (prune_data.nr == 1 && !strcmp(prune_data[0], ":")) {
* prune_data.nr = 0;
* prune_data.alloc = 0;
* free(prune_data.path);
* prune_data.path = NULL;
* } else {
* terminate prune_data.alloc with NULL and
* call init_pathspec() to set revs->prune_data here.
* }
*/
parse_pathspec(&revs->prune_data, 0, 0,
revs->prefix, prune_data.v);
}
strvec_clear(&prune_data);
if (revs->def == NULL)
revs->def = opt ? opt->def : NULL;
if (opt && opt->tweak)
opt->tweak(revs, opt);
if (revs->show_merge)
prepare_show_merge(revs);
revision: set rev_input_given in handle_revision_arg() Commit 7ba826290a (revision: add rev_input_given flag, 2017-08-02) added a flag to rev_info to tell whether we got any revision arguments. As explained there, this is necessary because some revision arguments may not produce any pending traversal objects, but should still inhibit default behaviors (e.g., a glob that matches nothing). However, it only set the flag in the globbing code, but not for revisions we get on the command-line or via stdin. This leads to two problems: - the command-line code keeps its own separate got_rev_arg flag; this isn't wrong, but it's confusing and an extra maintenance burden - even specifically-named rev arguments might end up not adding any pending objects: if --ignore-missing is set, then specifying a missing object is a noop rather than an error. And that leads to some user-visible bugs: - when deciding whether a default rev like "HEAD" should kick in, we check both got_rev_arg and rev_input_given. That means that "--ignore-missing $ZERO_OID" works on the command-line (where we set got_rev_arg) but not on --stdin (where we don't) - when rev-list decides whether it should complain that it wasn't given a starting point, it relies on rev_input_given. So it can't even get the command-line "--ignore-missing $ZERO_OID" right Let's consistently set the flag if we got any revision argument. That lets us clean up the redundant got_rev_arg, and fixes both of those bugs (but note there are three new tests: we'll confirm the already working git-log command-line case). A few implementation notes: - conceptually we want to set the flag whenever handle_revision_arg() finds an actual revision arg ("handles" it, you might say). But it covers a ton of cases with early returns. Rather than annotating each one, we just wrap it and use its success exit-code to set the flag in one spot. - the new rev-list test is in t6018, which is titled to cover globs. This isn't exactly a glob, but it made sense to stick it with the other tests that handle the "even though we got a rev, we have no pending objects" case, which are globs. - the tests check for the oid of a missing object, which it's pretty clear --ignore-missing should ignore. You can see the same behavior with "--ignore-missing a-ref-that-does-not-exist", because --ignore-missing treats them both the same. That's perhaps less clearly correct, and we may want to change that in the future. But the way the code and tests here are written, we'd continue to do the right thing even if it does. Reported-by: Bryan Turner <bturner@atlassian.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-26 20:13:05 +00:00
if (revs->def && !revs->pending.nr && !revs->rev_input_given) {
struct object_id oid;
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
struct object *object;
struct object_context oc;
if (get_oid_with_context(revs->repo, revs->def, 0, &oid, &oc))
diagnose_missing_default(revs->def);
object = get_reference(revs, revs->def, &oid, 0);
add_pending_object_with_mode(revs, object, revs->def, oc.mode);
}
/* Did the user ask for any diff output? Run the diff! */
if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
revs->diff = 1;
/* Pickaxe, diff-filter and rename following need diffs */
if ((revs->diffopt.pickaxe_opts & DIFF_PICKAXE_KINDS_MASK) ||
revs->diffopt.filter ||
diff: make struct diff_flags members lowercase Now that the flags stored in struct diff_flags are being accessed directly and not through macros, change all struct members from being uppercase to lowercase. This conversion is done using the following semantic patch: @@ expression E; @@ - E.RECURSIVE + E.recursive @@ expression E; @@ - E.TREE_IN_RECURSIVE + E.tree_in_recursive @@ expression E; @@ - E.BINARY + E.binary @@ expression E; @@ - E.TEXT + E.text @@ expression E; @@ - E.FULL_INDEX + E.full_index @@ expression E; @@ - E.SILENT_ON_REMOVE + E.silent_on_remove @@ expression E; @@ - E.FIND_COPIES_HARDER + E.find_copies_harder @@ expression E; @@ - E.FOLLOW_RENAMES + E.follow_renames @@ expression E; @@ - E.RENAME_EMPTY + E.rename_empty @@ expression E; @@ - E.HAS_CHANGES + E.has_changes @@ expression E; @@ - E.QUICK + E.quick @@ expression E; @@ - E.NO_INDEX + E.no_index @@ expression E; @@ - E.ALLOW_EXTERNAL + E.allow_external @@ expression E; @@ - E.EXIT_WITH_STATUS + E.exit_with_status @@ expression E; @@ - E.REVERSE_DIFF + E.reverse_diff @@ expression E; @@ - E.CHECK_FAILED + E.check_failed @@ expression E; @@ - E.RELATIVE_NAME + E.relative_name @@ expression E; @@ - E.IGNORE_SUBMODULES + E.ignore_submodules @@ expression E; @@ - E.DIRSTAT_CUMULATIVE + E.dirstat_cumulative @@ expression E; @@ - E.DIRSTAT_BY_FILE + E.dirstat_by_file @@ expression E; @@ - E.ALLOW_TEXTCONV + E.allow_textconv @@ expression E; @@ - E.TEXTCONV_SET_VIA_CMDLINE + E.textconv_set_via_cmdline @@ expression E; @@ - E.DIFF_FROM_CONTENTS + E.diff_from_contents @@ expression E; @@ - E.DIRTY_SUBMODULES + E.dirty_submodules @@ expression E; @@ - E.IGNORE_UNTRACKED_IN_SUBMODULES + E.ignore_untracked_in_submodules @@ expression E; @@ - E.IGNORE_DIRTY_SUBMODULES + E.ignore_dirty_submodules @@ expression E; @@ - E.OVERRIDE_SUBMODULE_CONFIG + E.override_submodule_config @@ expression E; @@ - E.DIRSTAT_BY_LINE + E.dirstat_by_line @@ expression E; @@ - E.FUNCCONTEXT + E.funccontext @@ expression E; @@ - E.PICKAXE_IGNORE_CASE + E.pickaxe_ignore_case @@ expression E; @@ - E.DEFAULT_FOLLOW_RENAMES + E.default_follow_renames Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-31 18:19:11 +00:00
revs->diffopt.flags.follow_renames)
revs->diff = 1;
diffcore: add a pickaxe option to find a specific blob Sometimes users are given a hash of an object and they want to identify it further (ex.: Use verify-pack to find the largest blobs, but what are these? or [1]) One might be tempted to extend git-describe to also work with blobs, such that `git describe <blob-id>` gives a description as '<commit-ish>:<path>'. This was implemented at [2]; as seen by the sheer number of responses (>110), it turns out this is tricky to get right. The hard part to get right is picking the correct 'commit-ish' as that could be the commit that (re-)introduced the blob or the blob that removed the blob; the blob could exist in different branches. Junio hinted at a different approach of solving this problem, which this patch implements. Teach the diff machinery another flag for restricting the information to what is shown. For example: $ ./git log --oneline --find-object=v2.0.0:Makefile b2feb64309 Revert the whole "ask curl-config" topic for now 47fbfded53 i18n: only extract comments marked with "TRANSLATORS:" we observe that the Makefile as shipped with 2.0 was appeared in v1.9.2-471-g47fbfded53 and in v2.0.0-rc1-5-gb2feb6430b. The reason why these commits both occur prior to v2.0.0 are evil merges that are not found using this new mechanism. [1] https://stackoverflow.com/questions/223678/which-commit-has-this-blob [2] https://public-inbox.org/git/20171028004419.10139-1-sbeller@google.com/ Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-01-04 22:50:42 +00:00
if (revs->diffopt.objfind)
revs->simplify_history = 0;
line-log: try to use generation number-based topo-ordering The previous patch made it possible to perform line-level filtering during history traversal instead of in an expensive preprocessing step, but it still requires some simpler preprocessing steps, notably topo-ordering. However, nowadays we have commit-graphs storing generation numbers, which make it possible to incrementally traverse the history in topological order, without the preparatory limit_list() and sort_in_topological_order() steps; see b45424181e (revision.c: generation-based topo-order algorithm, 2018-11-01). This patch combines the two, so we can do both the topo-ordering and the line-level filtering during history traversal, eliminating even those simpler preprocessing steps, and thus further reducing the delay before showing the first commit modifying the given line range. The 'revs->limited' flag plays the central role in this, because, due to limitations of the current implementation, the generation number-based topo-ordering is only enabled when this flag remains unset. Line-level log, however, always sets this flag in setup_revisions() ever since the feature was introduced in 12da1d1f6f (Implement line-history search (git log -L), 2013-03-28). The reason for setting 'limited' is unclear, though, because the line-level log itself doesn't directly depend on it, and it doesn't affect how the limit_list() function limits the revision range. However, there is an indirect dependency: the line-level log requires topo-ordering, and the "traditional" sort_in_topological_order() requires an already limited commit list since e6c3505b44 (Make sure we generate the whole commit list before trying to sort it topologically, 2005-07-06). The new, generation numbers-based topo-ordering doesn't require a limited commit list anymore. So don't set 'revs->limited' for line-level log, unless it is really necessary, namely: - The user explicitly requested parent rewriting, because that is still done in the line_log_filter() preprocessing step (see previous patch), which requires sort_in_topological_order() and in turn limit_list() as well. - A commit-graph file is not available or it doesn't yet contain generation numbers. In these cases we had to fall back on sort_in_topological_order() and in turn limit_list(). The existing condition with generation_numbers_enabled() has already ensured that the 'limited' flag is set in these cases; this patch just makes sure that the line-level log sets 'revs->topo_order' before that condition. While the reduced delay before showing the first commit is measurable in git.git, it takes a bigger repository to make it clearly noticable. In both cases below the line ranges were chosen so that they were modified rather close to the starting revisions, so the effect of this change is most noticable. # git.git $ time git --no-pager log -L:read_alternate_refs:sha1-file.c -1 v2.23.0 Before: real 0m0.107s user 0m0.091s sys 0m0.013s After: real 0m0.058s user 0m0.050s sys 0m0.005s # linux.git $ time git --no-pager log \ -L:build_restore_work_registers:arch/mips/mm/tlbex.c -1 v5.2 Before: real 0m1.129s user 0m1.061s sys 0m0.069s After: real 0m0.096s user 0m0.087s sys 0m0.009s Additional testing by Derrick Stolee: Since this patch improves the performance for the first result, I repeated the experiment from the previous patch on the Linux kernel repository, reporting real time here: Command: git log -L 100,200:MAINTAINERS -n 1 >/dev/null Before: 0.71 s After: 0.05 s Now, we have dropped the full topo-order of all ~910,000 commits before reporting the first result. The remaining performance improvements then are: 1. Update the parent-rewriting logic to be incremental similar to how "git log --graph" behaves. 2. Use changed-path Bloom filters to reduce the time spend in the tree-diff to see if the path(s) changed. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-11 11:56:18 +00:00
if (revs->line_level_traverse) {
if (want_ancestry(revs))
revs->limited = 1;
revs->topo_order = 1;
}
revision.c: begin refactoring --topo-order logic When running 'git rev-list --topo-order' and its kin, the topo_order setting in struct rev_info implies the limited setting. This means that the following things happen during prepare_revision_walk(): * revs->limited implies we run limit_list() to walk the entire reachable set. There are some short-cuts here, such as if we perform a range query like 'git rev-list COMPARE..HEAD' and we can stop limit_list() when all queued commits are uninteresting. * revs->topo_order implies we run sort_in_topological_order(). See the implementation of that method in commit.c. It implies that the full set of commits to order is in the given commit_list. These two methods imply that a 'git rev-list --topo-order HEAD' command must walk the entire reachable set of commits _twice_ before returning a single result. If we have a commit-graph file with generation numbers computed, then there is a better way. This patch introduces some necessary logic redirection when we are in this situation. In v2.18.0, the commit-graph file contains zero-valued bytes in the positions where the generation number is stored in v2.19.0 and later. Thus, we use generation_numbers_enabled() to check if the commit-graph is available and has non-zero generation numbers. When setting revs->limited only because revs->topo_order is true, only do so if generation numbers are not available. There is no reason to use the new logic as it will behave similarly when all generation numbers are INFINITY or ZERO. In prepare_revision_walk(), if we have revs->topo_order but not revs->limited, then we trigger the new logic. It breaks the logic into three pieces, to fit with the existing framework: 1. init_topo_walk() fills a new struct topo_walk_info in the rev_info struct. We use the presence of this struct as a signal to use the new methods during our walk. In this patch, this method simply calls limit_list() and sort_in_topological_order(). In the future, this method will set up a new data structure to perform that logic in-line. 2. next_topo_commit() provides get_revision_1() with the next topo- ordered commit in the list. Currently, this simply pops the commit from revs->commits. 3. expand_topo_walk() provides get_revision_1() with a way to signal walking beyond the latest commit. Currently, this calls add_parents_to_list() exactly like the old logic. While this commit presents method redirection for performing the exact same logic as before, it allows the next commit to focus only on the new logic. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:20 +00:00
if (revs->topo_order && !generation_numbers_enabled(the_repository))
revs->limited = 1;
if (revs->prune_data.nr) {
copy_pathspec(&revs->pruning.pathspec, &revs->prune_data);
Finally implement "git log --follow" Ok, I've really held off doing this too damn long, because I'm lazy, and I was always hoping that somebody else would do it. But no, people keep asking for it, but nobody actually did anything, so I decided I might as well bite the bullet, and instead of telling people they could add a "--follow" flag to "git log" to do what they want to do, I decided that it looks like I just have to do it for them.. The code wasn't actually that complicated, in that the diffstat for this patch literally says "70 insertions(+), 1 deletions(-)", but I will have to admit that in order to get to this fairly simple patch, you did have to know and understand the internal git diff generation machinery pretty well, and had to really be able to follow how commit generation interacts with generating patches and generating the log. So I suspect that while I was right that it wasn't that hard, I might have been expecting too much of random people - this patch does seem to be firmly in the core "Linus or Junio" territory. To make a long story short: I'm sorry for it taking so long until I just did it. I'm not going to guarantee that this works for everybody, but you really can just look at the patch, and after the appropriate appreciative noises ("Ooh, aah") over how clever I am, you can then just notice that the code itself isn't really that complicated. All the real new code is in the new "try_to_follow_renames()" function. It really isn't rocket science: we notice that the pathname we were looking at went away, so we start a full tree diff and try to see if we can instead make that pathname be a rename or a copy from some other previous pathname. And if we can, we just continue, except we show *that* particular diff, and ever after we use the _previous_ pathname. One thing to look out for: the "rename detection" is considered to be a singular event in the _linear_ "git log" output! That's what people want to do, but I just wanted to point out that this patch is *not* carrying around a "commit,pathname" kind of pair and it's *not* going to be able to notice the file coming from multiple *different* files in earlier history. IOW, if you use "git log --follow", then you get the stupid CVS/SVN kind of "files have single identities" kind of semantics, and git log will just pick the identity based on the normal move/copy heuristics _as_if_ the history could be linearized. Put another way: I think the model is broken, but given the broken model, I think this patch does just about as well as you can do. If you have merges with the same "file" having different filenames over the two branches, git will just end up picking _one_ of the pathnames at the point where the newer one goes away. It never looks at multiple pathnames in parallel. And if you understood all that, you probably didn't need it explained, and if you didn't understand the above blathering, it doesn't really mtter to you. What matters to you is that you can now do git log -p --follow builtin-rev-list.c and it will find the point where the old "rev-list.c" got renamed to "builtin-rev-list.c" and show it as such. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-06-19 21:22:46 +00:00
/* Can't prune commits with rename following: the paths change.. */
diff: make struct diff_flags members lowercase Now that the flags stored in struct diff_flags are being accessed directly and not through macros, change all struct members from being uppercase to lowercase. This conversion is done using the following semantic patch: @@ expression E; @@ - E.RECURSIVE + E.recursive @@ expression E; @@ - E.TREE_IN_RECURSIVE + E.tree_in_recursive @@ expression E; @@ - E.BINARY + E.binary @@ expression E; @@ - E.TEXT + E.text @@ expression E; @@ - E.FULL_INDEX + E.full_index @@ expression E; @@ - E.SILENT_ON_REMOVE + E.silent_on_remove @@ expression E; @@ - E.FIND_COPIES_HARDER + E.find_copies_harder @@ expression E; @@ - E.FOLLOW_RENAMES + E.follow_renames @@ expression E; @@ - E.RENAME_EMPTY + E.rename_empty @@ expression E; @@ - E.HAS_CHANGES + E.has_changes @@ expression E; @@ - E.QUICK + E.quick @@ expression E; @@ - E.NO_INDEX + E.no_index @@ expression E; @@ - E.ALLOW_EXTERNAL + E.allow_external @@ expression E; @@ - E.EXIT_WITH_STATUS + E.exit_with_status @@ expression E; @@ - E.REVERSE_DIFF + E.reverse_diff @@ expression E; @@ - E.CHECK_FAILED + E.check_failed @@ expression E; @@ - E.RELATIVE_NAME + E.relative_name @@ expression E; @@ - E.IGNORE_SUBMODULES + E.ignore_submodules @@ expression E; @@ - E.DIRSTAT_CUMULATIVE + E.dirstat_cumulative @@ expression E; @@ - E.DIRSTAT_BY_FILE + E.dirstat_by_file @@ expression E; @@ - E.ALLOW_TEXTCONV + E.allow_textconv @@ expression E; @@ - E.TEXTCONV_SET_VIA_CMDLINE + E.textconv_set_via_cmdline @@ expression E; @@ - E.DIFF_FROM_CONTENTS + E.diff_from_contents @@ expression E; @@ - E.DIRTY_SUBMODULES + E.dirty_submodules @@ expression E; @@ - E.IGNORE_UNTRACKED_IN_SUBMODULES + E.ignore_untracked_in_submodules @@ expression E; @@ - E.IGNORE_DIRTY_SUBMODULES + E.ignore_dirty_submodules @@ expression E; @@ - E.OVERRIDE_SUBMODULE_CONFIG + E.override_submodule_config @@ expression E; @@ - E.DIRSTAT_BY_LINE + E.dirstat_by_line @@ expression E; @@ - E.FUNCCONTEXT + E.funccontext @@ expression E; @@ - E.PICKAXE_IGNORE_CASE + E.pickaxe_ignore_case @@ expression E; @@ - E.DEFAULT_FOLLOW_RENAMES + E.default_follow_renames Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-31 18:19:11 +00:00
if (!revs->diffopt.flags.follow_renames)
revs->prune = 1;
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
if (!revs->full_diff)
copy_pathspec(&revs->diffopt.pathspec,
&revs->prune_data);
}
diff_merges_setup_revs(revs);
log,diff-tree: add --combined-all-paths option The combined diff format for merges will only list one filename, even if rename or copy detection is active. For example, with raw format one might see: ::100644 100644 100644 fabadb8 cc95eb0 4866510 MM describe.c ::100755 100755 100755 52b7a2d 6d1ac04 d2ac7d7 RM bar.sh ::100644 100644 100644 e07d6c5 9042e82 ee91881 RR phooey.c This doesn't let us know what the original name of bar.sh was in the first parent, and doesn't let us know what either of the original names of phooey.c were in either of the parents. In contrast, for non-merge commits, raw format does provide original filenames (and a rename score to boot). In order to also provide original filenames for merge commits, add a --combined-all-paths option (which must be used with either -c or --cc, and is likely only useful with rename or copy detection active) so that we can print tab-separated filenames when renames are involved. This transforms the above output to: ::100644 100644 100644 fabadb8 cc95eb0 4866510 MM desc.c desc.c desc.c ::100755 100755 100755 52b7a2d 6d1ac04 d2ac7d7 RM foo.sh bar.sh bar.sh ::100644 100644 100644 e07d6c5 9042e82 ee91881 RR fooey.c fuey.c phooey.c Further, in patch format, this changes the from/to headers so that instead of just having one "from" header, we get one for each parent. For example, instead of having --- a/phooey.c +++ b/phooey.c we would see --- a/fooey.c --- a/fuey.c +++ b/phooey.c Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-02-08 01:12:46 +00:00
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
revs->diffopt.abbrev = revs->abbrev;
Implement line-history search (git log -L) This is a rewrite of much of Bo's work, mainly in an effort to split it into smaller, easier to understand routines. The algorithm is built around the struct range_set, which encodes a series of line ranges as intervals [a,b). This is used in two contexts: * A set of lines we are tracking (which will change as we dig through history). * To encode diffs, as pairs of ranges. The main routine is range_set_map_across_diff(). It processes the diff between a commit C and some parent P. It determines which diff hunks are relevant to the ranges tracked in C, and computes the new ranges for P. The algorithm is then simply to process history in topological order from newest to oldest, computing ranges and (partial) diffs. At branch points, we need to merge the ranges we are watching. We will find that many commits do not affect the chosen ranges, and mark them TREESAME (in addition to those already filtered by pathspec limiting). Another pass of history simplification then gets rid of such commits. This is wired as an extra filtering pass in the log machinery. This currently only reduces code duplication, but should allow for other simplifications and options to be used. Finally, we hook a diff printer into the output chain. Ideally we would wire directly into the diff logic, to optionally use features like word diff. However, that will require some major reworking of the diff chain, so we completely replace the output with our own diff for now. As this was a GSoC project, and has quite some history by now, many people have helped. In no particular order, thanks go to Jakub Narebski <jnareb@gmail.com> Jens Lehmann <Jens.Lehmann@web.de> Jonathan Nieder <jrnieder@gmail.com> Junio C Hamano <gitster@pobox.com> Ramsay Jones <ramsay@ramsay1.demon.co.uk> Will Palmer <wmpalmer@gmail.com> Apologies to everyone I forgot. Signed-off-by: Bo Yang <struggleyb.nku@gmail.com> Signed-off-by: Thomas Rast <trast@student.ethz.ch> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-03-28 16:47:32 +00:00
diff_setup_done(&revs->diffopt);
if (!is_encoding_utf8(get_log_output_encoding()))
revs->grep_filter.ignore_locale = 1;
compile_grep_patterns(&revs->grep_filter);
if (revs->reverse && revs->reflog_info)
die(_("options '%s' and '%s' cannot be used together"), "--reverse", "--walk-reflogs");
if (revs->reflog_info && revs->limited)
die("cannot combine --walk-reflogs with history-limiting options");
if (revs->rewrite_parents && revs->children.name)
die(_("options '%s' and '%s' cannot be used together"), "--parents", "--children");
/*
* Limitations on the graph functionality
*/
if (revs->reverse && revs->graph)
die(_("options '%s' and '%s' cannot be used together"), "--reverse", "--graph");
if (revs->reflog_info && revs->graph)
die(_("options '%s' and '%s' cannot be used together"), "--walk-reflogs", "--graph");
if (revs->no_walk && revs->graph)
die(_("options '%s' and '%s' cannot be used together"), "--no-walk", "--graph");
if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
die(_("the option '%s' requires '%s'"), "--grep-reflog", "--walk-reflogs");
if (revs->line_level_traverse &&
(revs->diffopt.output_format & ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT)))
die(_("-L does not yet support diff formats besides -p and -s"));
if (revs->expand_tabs_in_log < 0)
revs->expand_tabs_in_log = revs->expand_tabs_in_log_default;
return left;
}
static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
{
struct commit_list *l = xcalloc(1, sizeof(*l));
l->item = child;
l->next = add_decoration(&revs->children, &parent->object, l);
}
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
static int remove_duplicate_parents(struct rev_info *revs, struct commit *commit)
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
{
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
struct commit_list **pp, *p;
int surviving_parents;
/* Examine existing parents while marking ones we have seen... */
pp = &commit->parents;
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
surviving_parents = 0;
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
while ((p = *pp) != NULL) {
struct commit *parent = p->item;
if (parent->object.flags & TMP_MARK) {
*pp = p->next;
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
if (ts)
compact_treesame(revs, commit, surviving_parents);
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
continue;
}
parent->object.flags |= TMP_MARK;
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
surviving_parents++;
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
pp = &p->next;
}
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
/* clear the temporary mark */
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
for (p = commit->parents; p; p = p->next) {
p->item->object.flags &= ~TMP_MARK;
}
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
/* no update_treesame() - removing duplicates can't affect TREESAME */
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
return surviving_parents;
}
struct merge_simplify_state {
struct commit *simplified;
};
static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
{
struct merge_simplify_state *st;
st = lookup_decoration(&revs->merge_simplification, &commit->object);
if (!st) {
CALLOC_ARRAY(st, 1);
add_decoration(&revs->merge_simplification, &commit->object, st);
}
return st;
}
static int mark_redundant_parents(struct commit *commit)
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
{
struct commit_list *h = reduce_heads(commit->parents);
int i = 0, marked = 0;
struct commit_list *po, *pn;
/* Want these for sanity-checking only */
int orig_cnt = commit_list_count(commit->parents);
int cnt = commit_list_count(h);
/*
* Not ready to remove items yet, just mark them for now, based
* on the output of reduce_heads(). reduce_heads outputs the reduced
* set in its original order, so this isn't too hard.
*/
po = commit->parents;
pn = h;
while (po) {
if (pn && po->item == pn->item) {
pn = pn->next;
i++;
} else {
po->item->object.flags |= TMP_MARK;
marked++;
}
po=po->next;
}
if (i != cnt || cnt+marked != orig_cnt)
die("mark_redundant_parents %d %d %d %d", orig_cnt, cnt, i, marked);
free_commit_list(h);
return marked;
}
static int mark_treesame_root_parents(struct commit *commit)
{
struct commit_list *p;
int marked = 0;
for (p = commit->parents; p; p = p->next) {
struct commit *parent = p->item;
if (!parent->parents && (parent->object.flags & TREESAME)) {
parent->object.flags |= TMP_MARK;
marked++;
}
}
return marked;
}
/*
* Awkward naming - this means one parent we are TREESAME to.
* cf mark_treesame_root_parents: root parents that are TREESAME (to an
* empty tree). Better name suggestions?
*/
static int leave_one_treesame_to_parent(struct rev_info *revs, struct commit *commit)
{
struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
struct commit *unmarked = NULL, *marked = NULL;
struct commit_list *p;
unsigned n;
for (p = commit->parents, n = 0; p; p = p->next, n++) {
if (ts->treesame[n]) {
if (p->item->object.flags & TMP_MARK) {
if (!marked)
marked = p->item;
} else {
if (!unmarked) {
unmarked = p->item;
break;
}
}
}
}
/*
* If we are TREESAME to a marked-for-deletion parent, but not to any
* unmarked parents, unmark the first TREESAME parent. This is the
* parent that the default simplify_history==1 scan would have followed,
* and it doesn't make sense to omit that path when asking for a
* simplified full history. Retaining it improves the chances of
* understanding odd missed merges that took an old version of a file.
*
* Example:
*
* I--------*X A modified the file, but mainline merge X used
* \ / "-s ours", so took the version from I. X is
* `-*A--' TREESAME to I and !TREESAME to A.
*
* Default log from X would produce "I". Without this check,
* --full-history --simplify-merges would produce "I-A-X", showing
* the merge commit X and that it changed A, but not making clear that
* it had just taken the I version. With this check, the topology above
* is retained.
*
* Note that it is possible that the simplification chooses a different
* TREESAME parent from the default, in which case this test doesn't
* activate, and we _do_ drop the default parent. Example:
*
* I------X A modified the file, but it was reverted in B,
* \ / meaning mainline merge X is TREESAME to both
* *A-*B parents.
*
* Default log would produce "I" by following the first parent;
* --full-history --simplify-merges will produce "I-A-B". But this is a
* reasonable result - it presents a logical full history leading from
* I to X, and X is not an important merge.
*/
if (!unmarked && marked) {
marked->object.flags &= ~TMP_MARK;
return 1;
}
return 0;
}
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
static int remove_marked_parents(struct rev_info *revs, struct commit *commit)
{
struct commit_list **pp, *p;
int nth_parent, removed = 0;
pp = &commit->parents;
nth_parent = 0;
while ((p = *pp) != NULL) {
struct commit *parent = p->item;
if (parent->object.flags & TMP_MARK) {
parent->object.flags &= ~TMP_MARK;
*pp = p->next;
free(p);
removed++;
compact_treesame(revs, commit, nth_parent);
continue;
}
pp = &p->next;
nth_parent++;
}
/* Removing parents can only increase TREESAMEness */
if (removed && !(commit->object.flags & TREESAME))
update_treesame(revs, commit);
return nth_parent;
}
static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
{
struct commit_list *p;
struct commit *parent;
struct merge_simplify_state *st, *pst;
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
int cnt;
st = locate_simplify_state(revs, commit);
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
/*
* Have we handled this one?
*/
if (st->simplified)
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
return tail;
/*
* An UNINTERESTING commit simplifies to itself, so does a
* root commit. We do not rewrite parents of such commit
* anyway.
*/
if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
st->simplified = commit;
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
return tail;
}
/*
* Do we know what commit all of our parents that matter
* should be rewritten to? Otherwise we are not ready to
* rewrite this one yet.
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
*/
for (cnt = 0, p = commit->parents; p; p = p->next) {
pst = locate_simplify_state(revs, p->item);
if (!pst->simplified) {
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
tail = &commit_list_insert(p->item, tail)->next;
cnt++;
}
if (revs->first_parent_only)
break;
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
}
if (cnt) {
tail = &commit_list_insert(commit, tail)->next;
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
return tail;
}
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
/*
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
* Rewrite our list of parents. Note that this cannot
* affect our TREESAME flags in any way - a commit is
* always TREESAME to its simplification.
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
*/
for (p = commit->parents; p; p = p->next) {
pst = locate_simplify_state(revs, p->item);
p->item = pst->simplified;
if (revs->first_parent_only)
break;
}
if (revs->first_parent_only)
cnt = 1;
else
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
cnt = remove_duplicate_parents(revs, commit);
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
/*
* It is possible that we are a merge and one side branch
* does not have any commit that touches the given paths;
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
* in such a case, the immediate parent from that branch
* will be rewritten to be the merge base.
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
*
* o----X X: the commit we are looking at;
* / / o: a commit that touches the paths;
* ---o----'
*
* Further, a merge of an independent branch that doesn't
* touch the path will reduce to a treesame root parent:
*
* ----o----X X: the commit we are looking at;
* / o: a commit that touches the paths;
* r r: a root commit not touching the paths
*
* Detect and simplify both cases.
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
*/
if (1 < cnt) {
int marked = mark_redundant_parents(commit);
marked += mark_treesame_root_parents(commit);
if (marked)
marked -= leave_one_treesame_to_parent(revs, commit);
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
if (marked)
cnt = remove_marked_parents(revs, commit);
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
}
/*
* A commit simplifies to itself if it is a root, if it is
* UNINTERESTING, if it touches the given paths, or if it is a
* merge and its parents don't simplify to one relevant commit
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
* (the first two cases are already handled at the beginning of
* this function).
*
* Otherwise, it simplifies to what its sole relevant parent
* simplifies to.
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
*/
if (!cnt ||
(commit->object.flags & UNINTERESTING) ||
!(commit->object.flags & TREESAME) ||
revision: --show-pulls adds helpful merges The default file history simplification of "git log -- <path>" or "git rev-list -- <path>" focuses on providing the smallest set of commits that first contributed a change. The revision walk greatly restricts the set of walked commits by visiting only the first TREESAME parent of a merge commit, when one exists. This means that portions of the commit-graph are not walked, which can be a performance benefit, but can also "hide" commits that added changes but were ignored by a merge resolution. The --full-history option modifies this by walking all commits and reporting a merge commit as "interesting" if it has _any_ parent that is not TREESAME. This tends to be an over-representation of important commits, especially in an environment where most merge commits are created by pull request completion. Suppose we have a commit A and we create a commit B on top that changes our file. When we merge the pull request, we create a merge commit M. If no one else changed the file in the first-parent history between M and A, then M will not be TREESAME to its first parent, but will be TREESAME to B. Thus, the simplified history will be "B". However, M will appear in the --full-history mode. However, suppose that a number of topics T1, T2, ..., Tn were created based on commits C1, C2, ..., Cn between A and M as follows: A----C1----C2--- ... ---Cn----M------P1---P2--- ... ---Pn \ \ \ \ / / / / \ \__.. \ \/ ..__T1 / Tn \ \__.. /\ ..__T2 / \_____________________B \____________________/ If the commits T1, T2, ... Tn did not change the file, then all of P1 through Pn will be TREESAME to their first parent, but not TREESAME to their second. This means that all of those merge commits appear in the --full-history view, with edges that immediately collapse into the lower history without introducing interesting single-parent commits. The --simplify-merges option was introduced to remove these extra merge commits. By noticing that the rewritten parents are reachable from their first parents, those edges can be simplified away. Finally, the commits now look like single-parent commits that are TREESAME to their "only" parent. Thus, they are removed and this issue does not cause issues anymore. However, this also ends up removing the commit M from the history view! Even worse, the --simplify-merges option requires walking the entire history before returning a single result. Many Git users are using Git alongside a Git service that provides code storage alongside a code review tool commonly called "Pull Requests" or "Merge Requests" against a target branch. When these requests are accepted and merged, they typically create a merge commit whose first parent is the previous branch tip and the second parent is the tip of the topic branch used for the request. This presents a valuable order to the parents, but also makes that merge commit slightly special. Users may want to see not only which commits changed a file, but which pull requests merged those commits into their branch. In the previous example, this would mean the users want to see the merge commit "M" in addition to the single- parent commit "C". Users are even more likely to want these merge commits when they use pull requests to merge into a feature branch before merging that feature branch into their trunk. In some sense, users are asking for the "first" merge commit to bring in the change to their branch. As long as the parent order is consistent, this can be handled with the following rule: Include a merge commit if it is not TREESAME to its first parent, but is TREESAME to a later parent. These merges look like the merge commits that would result from running "git pull <topic>" on a main branch. Thus, the option to show these commits is called "--show-pulls". This has the added benefit of showing the commits created by closing a pull request or merge request on any of the Git hosting and code review platforms. To test these options, extend the standard test example to include a merge commit that is not TREESAME to its first parent. It is surprising that that option was not already in the example, as it is instructive. In particular, this extension demonstrates a common issue with file history simplification. When a user resolves a merge conflict using "-Xours" or otherwise ignoring one side of the conflict, they create a TREESAME edge that probably should not be TREESAME. This leads users to become frustrated and complain that "my change disappeared!" In my experience, showing them history with --full-history and --simplify-merges quickly reveals the problematic merge. As mentioned, this option is expensive to compute. The --show-pulls option _might_ show the merge commit (usually titled "resolving conflicts") more quickly. Of course, this depends on the user having the correct parent order, which is backwards when using "git pull master" from a topic branch. There are some special considerations when combining the --show-pulls option with --simplify-merges. This requires adding a new PULL_MERGE object flag to store the information from the initial TREESAME comparisons. This helps avoid dropping those commits in later filters. This is covered by a test, including how the parents can be simplified. Since "struct object" has already ruined its 32-bit alignment by using 33 bits across parsed, type, and flags member, let's not make it worse. PULL_MERGE is used in revision.c with the same value (1u<<15) as REACHABLE in commit-graph.c. The REACHABLE flag is only used when writing a commit-graph file, and a revision walk using --show-pulls does not happen in the same process. Care must be taken in the future to ensure this remains the case. Update Documentation/rev-list-options.txt with significant details around this option. This requires updating the example in the History Simplification section to demonstrate some of the problems with TREESAME second parents. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-10 12:19:43 +00:00
(parent = one_relevant_parent(revs, commit->parents)) == NULL ||
(revs->show_pulls && (commit->object.flags & PULL_MERGE)))
st->simplified = commit;
else {
pst = locate_simplify_state(revs, parent);
st->simplified = pst->simplified;
}
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
return tail;
}
static void simplify_merges(struct rev_info *revs)
{
struct commit_list *list, *next;
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
struct commit_list *yet_to_do, **tail;
struct commit *commit;
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
if (!revs->prune)
return;
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
/* feed the list reversed */
yet_to_do = NULL;
for (list = revs->commits; list; list = next) {
commit = list->item;
next = list->next;
/*
* Do not free(list) here yet; the original list
* is used later in this function.
*/
commit_list_insert(commit, &yet_to_do);
}
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
while (yet_to_do) {
list = yet_to_do;
yet_to_do = NULL;
tail = &yet_to_do;
while (list) {
commit = pop_commit(&list);
tail = simplify_one(revs, commit, tail);
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
}
}
/* clean up the result, removing the simplified ones */
list = revs->commits;
revs->commits = NULL;
tail = &revs->commits;
while (list) {
struct merge_simplify_state *st;
commit = pop_commit(&list);
st = locate_simplify_state(revs, commit);
if (st->simplified == commit)
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
tail = &commit_list_insert(commit, tail)->next;
}
}
static void set_children(struct rev_info *revs)
{
struct commit_list *l;
for (l = revs->commits; l; l = l->next) {
struct commit *commit = l->item;
struct commit_list *p;
for (p = commit->parents; p; p = p->next)
add_child(revs, p->item, commit);
}
}
void reset_revision_walk(void)
{
clear_object_flags(SEEN | ADDED | SHOWN | TOPO_WALK_EXPLORED | TOPO_WALK_INDEGREE);
}
static int mark_uninteresting(const struct object_id *oid,
struct packed_git *pack,
uint32_t pos,
void *cb)
{
struct rev_info *revs = cb;
revision: avoid parsing with --exclude-promisor-objects When --exclude-promisor-objects is given, before traversing any objects we iterate over all of the objects in any promisor packs, marking them as UNINTERESTING and SEEN. We turn the oid we get from iterating the pack into an object with parse_object(), but this has two problems: - it's slow; we are zlib inflating (and reconstructing from deltas) every byte of every object in the packfile - it leaves the tree buffers attached to their structs, which means our heap usage will grow to store every uncompressed tree simultaneously. This can be gigabytes. We can obviously fix the second by freeing the tree buffers after we've parsed them. But we can observe that the function doesn't look at the object contents at all! The only reason we call parse_object() is that we need a "struct object" on which to set the flags. There are two options here: - we can look up just the object type via oid_object_info(), and then call the appropriate lookup_foo() function - we can call lookup_unknown_object(), which gives us an OBJ_NONE struct (which will get auto-converted later by object_as_type() via calls to lookup_commit(), etc). The first one is closer to the current code, but we do pay the price to look up the type for each object. The latter should be more efficient in CPU, though it wastes a little bit of memory (the "unknown" object structs are a union of all object types, so some of the structs are bigger than they need to be). It also runs the risk of triggering a latent bug in code that calls lookup_object() directly but isn't ready to handle OBJ_NONE (such code would already be buggy, but we use lookup_unknown_object() infrequently enough that it might be hiding). I went with the second option here. I don't think the risk is high (and we'd want to find and fix any such bugs anyway), and it should be more efficient overall. The new tests in p5600 show off the improvement (this is on git.git): Test HEAD^ HEAD ------------------------------------------------------------------------------- 5600.5: count commits 0.37(0.37+0.00) 0.38(0.38+0.00) +2.7% 5600.6: count non-promisor commits 11.74(11.37+0.37) 0.04(0.03+0.00) -99.7% The improvement is particularly big in this script because _every_ object in the newly-cloned partial repo is a promisor object. So after marking them all, there's nothing left to traverse. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-13 07:17:48 +00:00
struct object *o = lookup_unknown_object(revs->repo, oid);
o->flags |= UNINTERESTING | SEEN;
return 0;
}
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
define_commit_slab(indegree_slab, int);
define_commit_slab(author_date_slab, timestamp_t);
struct topo_walk_info {
timestamp_t min_generation;
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
struct prio_queue explore_queue;
struct prio_queue indegree_queue;
struct prio_queue topo_queue;
struct indegree_slab indegree;
struct author_date_slab author_date;
};
static int topo_walk_atexit_registered;
static unsigned int count_explore_walked;
static unsigned int count_indegree_walked;
static unsigned int count_topo_walked;
static void trace2_topo_walk_statistics_atexit(void)
{
struct json_writer jw = JSON_WRITER_INIT;
jw_object_begin(&jw, 0);
jw_object_intmax(&jw, "count_explore_walked", count_explore_walked);
jw_object_intmax(&jw, "count_indegree_walked", count_indegree_walked);
jw_object_intmax(&jw, "count_topo_walked", count_topo_walked);
jw_end(&jw);
trace2_data_json("topo_walk", the_repository, "statistics", &jw);
jw_release(&jw);
}
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
static inline void test_flag_and_insert(struct prio_queue *q, struct commit *c, int flag)
{
if (c->object.flags & flag)
return;
c->object.flags |= flag;
prio_queue_put(q, c);
}
static void explore_walk_step(struct rev_info *revs)
{
struct topo_walk_info *info = revs->topo_walk_info;
struct commit_list *p;
struct commit *c = prio_queue_get(&info->explore_queue);
if (!c)
return;
if (repo_parse_commit_gently(revs->repo, c, 1) < 0)
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
return;
count_explore_walked++;
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
if (revs->sort_order == REV_SORT_BY_AUTHOR_DATE)
record_author_date(&info->author_date, c);
if (revs->max_age != -1 && (c->date < revs->max_age))
c->object.flags |= UNINTERESTING;
if (process_parents(revs, c, NULL, NULL) < 0)
return;
if (c->object.flags & UNINTERESTING)
mark_parents_uninteresting(revs, c);
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
for (p = c->parents; p; p = p->next)
test_flag_and_insert(&info->explore_queue, p->item, TOPO_WALK_EXPLORED);
}
static void explore_to_depth(struct rev_info *revs,
timestamp_t gen_cutoff)
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
{
struct topo_walk_info *info = revs->topo_walk_info;
struct commit *c;
while ((c = prio_queue_peek(&info->explore_queue)) &&
commit_graph_generation(c) >= gen_cutoff)
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
explore_walk_step(revs);
}
static void indegree_walk_step(struct rev_info *revs)
{
struct commit_list *p;
struct topo_walk_info *info = revs->topo_walk_info;
struct commit *c = prio_queue_get(&info->indegree_queue);
if (!c)
return;
if (repo_parse_commit_gently(revs->repo, c, 1) < 0)
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
return;
count_indegree_walked++;
explore_to_depth(revs, commit_graph_generation(c));
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
for (p = c->parents; p; p = p->next) {
struct commit *parent = p->item;
int *pi = indegree_slab_at(&info->indegree, parent);
if (repo_parse_commit_gently(revs->repo, parent, 1) < 0)
return;
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
if (*pi)
(*pi)++;
else
*pi = 2;
test_flag_and_insert(&info->indegree_queue, parent, TOPO_WALK_INDEGREE);
if (revs->first_parent_only)
return;
}
}
static void compute_indegrees_to_depth(struct rev_info *revs,
timestamp_t gen_cutoff)
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
{
struct topo_walk_info *info = revs->topo_walk_info;
struct commit *c;
while ((c = prio_queue_peek(&info->indegree_queue)) &&
commit_graph_generation(c) >= gen_cutoff)
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
indegree_walk_step(revs);
}
revision.c: begin refactoring --topo-order logic When running 'git rev-list --topo-order' and its kin, the topo_order setting in struct rev_info implies the limited setting. This means that the following things happen during prepare_revision_walk(): * revs->limited implies we run limit_list() to walk the entire reachable set. There are some short-cuts here, such as if we perform a range query like 'git rev-list COMPARE..HEAD' and we can stop limit_list() when all queued commits are uninteresting. * revs->topo_order implies we run sort_in_topological_order(). See the implementation of that method in commit.c. It implies that the full set of commits to order is in the given commit_list. These two methods imply that a 'git rev-list --topo-order HEAD' command must walk the entire reachable set of commits _twice_ before returning a single result. If we have a commit-graph file with generation numbers computed, then there is a better way. This patch introduces some necessary logic redirection when we are in this situation. In v2.18.0, the commit-graph file contains zero-valued bytes in the positions where the generation number is stored in v2.19.0 and later. Thus, we use generation_numbers_enabled() to check if the commit-graph is available and has non-zero generation numbers. When setting revs->limited only because revs->topo_order is true, only do so if generation numbers are not available. There is no reason to use the new logic as it will behave similarly when all generation numbers are INFINITY or ZERO. In prepare_revision_walk(), if we have revs->topo_order but not revs->limited, then we trigger the new logic. It breaks the logic into three pieces, to fit with the existing framework: 1. init_topo_walk() fills a new struct topo_walk_info in the rev_info struct. We use the presence of this struct as a signal to use the new methods during our walk. In this patch, this method simply calls limit_list() and sort_in_topological_order(). In the future, this method will set up a new data structure to perform that logic in-line. 2. next_topo_commit() provides get_revision_1() with the next topo- ordered commit in the list. Currently, this simply pops the commit from revs->commits. 3. expand_topo_walk() provides get_revision_1() with a way to signal walking beyond the latest commit. Currently, this calls add_parents_to_list() exactly like the old logic. While this commit presents method redirection for performing the exact same logic as before, it allows the next commit to focus only on the new logic. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:20 +00:00
static void reset_topo_walk(struct rev_info *revs)
{
struct topo_walk_info *info = revs->topo_walk_info;
clear_prio_queue(&info->explore_queue);
clear_prio_queue(&info->indegree_queue);
clear_prio_queue(&info->topo_queue);
clear_indegree_slab(&info->indegree);
clear_author_date_slab(&info->author_date);
FREE_AND_NULL(revs->topo_walk_info);
}
revision.c: begin refactoring --topo-order logic When running 'git rev-list --topo-order' and its kin, the topo_order setting in struct rev_info implies the limited setting. This means that the following things happen during prepare_revision_walk(): * revs->limited implies we run limit_list() to walk the entire reachable set. There are some short-cuts here, such as if we perform a range query like 'git rev-list COMPARE..HEAD' and we can stop limit_list() when all queued commits are uninteresting. * revs->topo_order implies we run sort_in_topological_order(). See the implementation of that method in commit.c. It implies that the full set of commits to order is in the given commit_list. These two methods imply that a 'git rev-list --topo-order HEAD' command must walk the entire reachable set of commits _twice_ before returning a single result. If we have a commit-graph file with generation numbers computed, then there is a better way. This patch introduces some necessary logic redirection when we are in this situation. In v2.18.0, the commit-graph file contains zero-valued bytes in the positions where the generation number is stored in v2.19.0 and later. Thus, we use generation_numbers_enabled() to check if the commit-graph is available and has non-zero generation numbers. When setting revs->limited only because revs->topo_order is true, only do so if generation numbers are not available. There is no reason to use the new logic as it will behave similarly when all generation numbers are INFINITY or ZERO. In prepare_revision_walk(), if we have revs->topo_order but not revs->limited, then we trigger the new logic. It breaks the logic into three pieces, to fit with the existing framework: 1. init_topo_walk() fills a new struct topo_walk_info in the rev_info struct. We use the presence of this struct as a signal to use the new methods during our walk. In this patch, this method simply calls limit_list() and sort_in_topological_order(). In the future, this method will set up a new data structure to perform that logic in-line. 2. next_topo_commit() provides get_revision_1() with the next topo- ordered commit in the list. Currently, this simply pops the commit from revs->commits. 3. expand_topo_walk() provides get_revision_1() with a way to signal walking beyond the latest commit. Currently, this calls add_parents_to_list() exactly like the old logic. While this commit presents method redirection for performing the exact same logic as before, it allows the next commit to focus only on the new logic. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:20 +00:00
static void init_topo_walk(struct rev_info *revs)
{
struct topo_walk_info *info;
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
struct commit_list *list;
if (revs->topo_walk_info)
reset_topo_walk(revs);
revision.c: begin refactoring --topo-order logic When running 'git rev-list --topo-order' and its kin, the topo_order setting in struct rev_info implies the limited setting. This means that the following things happen during prepare_revision_walk(): * revs->limited implies we run limit_list() to walk the entire reachable set. There are some short-cuts here, such as if we perform a range query like 'git rev-list COMPARE..HEAD' and we can stop limit_list() when all queued commits are uninteresting. * revs->topo_order implies we run sort_in_topological_order(). See the implementation of that method in commit.c. It implies that the full set of commits to order is in the given commit_list. These two methods imply that a 'git rev-list --topo-order HEAD' command must walk the entire reachable set of commits _twice_ before returning a single result. If we have a commit-graph file with generation numbers computed, then there is a better way. This patch introduces some necessary logic redirection when we are in this situation. In v2.18.0, the commit-graph file contains zero-valued bytes in the positions where the generation number is stored in v2.19.0 and later. Thus, we use generation_numbers_enabled() to check if the commit-graph is available and has non-zero generation numbers. When setting revs->limited only because revs->topo_order is true, only do so if generation numbers are not available. There is no reason to use the new logic as it will behave similarly when all generation numbers are INFINITY or ZERO. In prepare_revision_walk(), if we have revs->topo_order but not revs->limited, then we trigger the new logic. It breaks the logic into three pieces, to fit with the existing framework: 1. init_topo_walk() fills a new struct topo_walk_info in the rev_info struct. We use the presence of this struct as a signal to use the new methods during our walk. In this patch, this method simply calls limit_list() and sort_in_topological_order(). In the future, this method will set up a new data structure to perform that logic in-line. 2. next_topo_commit() provides get_revision_1() with the next topo- ordered commit in the list. Currently, this simply pops the commit from revs->commits. 3. expand_topo_walk() provides get_revision_1() with a way to signal walking beyond the latest commit. Currently, this calls add_parents_to_list() exactly like the old logic. While this commit presents method redirection for performing the exact same logic as before, it allows the next commit to focus only on the new logic. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:20 +00:00
revs->topo_walk_info = xmalloc(sizeof(struct topo_walk_info));
info = revs->topo_walk_info;
memset(info, 0, sizeof(struct topo_walk_info));
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
init_indegree_slab(&info->indegree);
memset(&info->explore_queue, 0, sizeof(info->explore_queue));
memset(&info->indegree_queue, 0, sizeof(info->indegree_queue));
memset(&info->topo_queue, 0, sizeof(info->topo_queue));
switch (revs->sort_order) {
default: /* REV_SORT_IN_GRAPH_ORDER */
info->topo_queue.compare = NULL;
break;
case REV_SORT_BY_COMMIT_DATE:
info->topo_queue.compare = compare_commits_by_commit_date;
break;
case REV_SORT_BY_AUTHOR_DATE:
init_author_date_slab(&info->author_date);
info->topo_queue.compare = compare_commits_by_author_date;
info->topo_queue.cb_data = &info->author_date;
break;
}
info->explore_queue.compare = compare_commits_by_gen_then_commit_date;
info->indegree_queue.compare = compare_commits_by_gen_then_commit_date;
info->min_generation = GENERATION_NUMBER_INFINITY;
for (list = revs->commits; list; list = list->next) {
struct commit *c = list->item;
timestamp_t generation;
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
if (repo_parse_commit_gently(revs->repo, c, 1))
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
continue;
test_flag_and_insert(&info->explore_queue, c, TOPO_WALK_EXPLORED);
test_flag_and_insert(&info->indegree_queue, c, TOPO_WALK_INDEGREE);
generation = commit_graph_generation(c);
if (generation < info->min_generation)
info->min_generation = generation;
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
*(indegree_slab_at(&info->indegree, c)) = 1;
if (revs->sort_order == REV_SORT_BY_AUTHOR_DATE)
record_author_date(&info->author_date, c);
}
compute_indegrees_to_depth(revs, info->min_generation);
for (list = revs->commits; list; list = list->next) {
struct commit *c = list->item;
if (*(indegree_slab_at(&info->indegree, c)) == 1)
prio_queue_put(&info->topo_queue, c);
}
/*
* This is unfortunate; the initial tips need to be shown
* in the order given from the revision traversal machinery.
*/
if (revs->sort_order == REV_SORT_IN_GRAPH_ORDER)
prio_queue_reverse(&info->topo_queue);
if (trace2_is_enabled() && !topo_walk_atexit_registered) {
atexit(trace2_topo_walk_statistics_atexit);
topo_walk_atexit_registered = 1;
}
revision.c: begin refactoring --topo-order logic When running 'git rev-list --topo-order' and its kin, the topo_order setting in struct rev_info implies the limited setting. This means that the following things happen during prepare_revision_walk(): * revs->limited implies we run limit_list() to walk the entire reachable set. There are some short-cuts here, such as if we perform a range query like 'git rev-list COMPARE..HEAD' and we can stop limit_list() when all queued commits are uninteresting. * revs->topo_order implies we run sort_in_topological_order(). See the implementation of that method in commit.c. It implies that the full set of commits to order is in the given commit_list. These two methods imply that a 'git rev-list --topo-order HEAD' command must walk the entire reachable set of commits _twice_ before returning a single result. If we have a commit-graph file with generation numbers computed, then there is a better way. This patch introduces some necessary logic redirection when we are in this situation. In v2.18.0, the commit-graph file contains zero-valued bytes in the positions where the generation number is stored in v2.19.0 and later. Thus, we use generation_numbers_enabled() to check if the commit-graph is available and has non-zero generation numbers. When setting revs->limited only because revs->topo_order is true, only do so if generation numbers are not available. There is no reason to use the new logic as it will behave similarly when all generation numbers are INFINITY or ZERO. In prepare_revision_walk(), if we have revs->topo_order but not revs->limited, then we trigger the new logic. It breaks the logic into three pieces, to fit with the existing framework: 1. init_topo_walk() fills a new struct topo_walk_info in the rev_info struct. We use the presence of this struct as a signal to use the new methods during our walk. In this patch, this method simply calls limit_list() and sort_in_topological_order(). In the future, this method will set up a new data structure to perform that logic in-line. 2. next_topo_commit() provides get_revision_1() with the next topo- ordered commit in the list. Currently, this simply pops the commit from revs->commits. 3. expand_topo_walk() provides get_revision_1() with a way to signal walking beyond the latest commit. Currently, this calls add_parents_to_list() exactly like the old logic. While this commit presents method redirection for performing the exact same logic as before, it allows the next commit to focus only on the new logic. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:20 +00:00
}
static struct commit *next_topo_commit(struct rev_info *revs)
{
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
struct commit *c;
struct topo_walk_info *info = revs->topo_walk_info;
/* pop next off of topo_queue */
c = prio_queue_get(&info->topo_queue);
if (c)
*(indegree_slab_at(&info->indegree, c)) = 0;
return c;
revision.c: begin refactoring --topo-order logic When running 'git rev-list --topo-order' and its kin, the topo_order setting in struct rev_info implies the limited setting. This means that the following things happen during prepare_revision_walk(): * revs->limited implies we run limit_list() to walk the entire reachable set. There are some short-cuts here, such as if we perform a range query like 'git rev-list COMPARE..HEAD' and we can stop limit_list() when all queued commits are uninteresting. * revs->topo_order implies we run sort_in_topological_order(). See the implementation of that method in commit.c. It implies that the full set of commits to order is in the given commit_list. These two methods imply that a 'git rev-list --topo-order HEAD' command must walk the entire reachable set of commits _twice_ before returning a single result. If we have a commit-graph file with generation numbers computed, then there is a better way. This patch introduces some necessary logic redirection when we are in this situation. In v2.18.0, the commit-graph file contains zero-valued bytes in the positions where the generation number is stored in v2.19.0 and later. Thus, we use generation_numbers_enabled() to check if the commit-graph is available and has non-zero generation numbers. When setting revs->limited only because revs->topo_order is true, only do so if generation numbers are not available. There is no reason to use the new logic as it will behave similarly when all generation numbers are INFINITY or ZERO. In prepare_revision_walk(), if we have revs->topo_order but not revs->limited, then we trigger the new logic. It breaks the logic into three pieces, to fit with the existing framework: 1. init_topo_walk() fills a new struct topo_walk_info in the rev_info struct. We use the presence of this struct as a signal to use the new methods during our walk. In this patch, this method simply calls limit_list() and sort_in_topological_order(). In the future, this method will set up a new data structure to perform that logic in-line. 2. next_topo_commit() provides get_revision_1() with the next topo- ordered commit in the list. Currently, this simply pops the commit from revs->commits. 3. expand_topo_walk() provides get_revision_1() with a way to signal walking beyond the latest commit. Currently, this calls add_parents_to_list() exactly like the old logic. While this commit presents method redirection for performing the exact same logic as before, it allows the next commit to focus only on the new logic. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:20 +00:00
}
static void expand_topo_walk(struct rev_info *revs, struct commit *commit)
{
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
struct commit_list *p;
struct topo_walk_info *info = revs->topo_walk_info;
if (process_parents(revs, commit, NULL, NULL) < 0) {
revision.c: begin refactoring --topo-order logic When running 'git rev-list --topo-order' and its kin, the topo_order setting in struct rev_info implies the limited setting. This means that the following things happen during prepare_revision_walk(): * revs->limited implies we run limit_list() to walk the entire reachable set. There are some short-cuts here, such as if we perform a range query like 'git rev-list COMPARE..HEAD' and we can stop limit_list() when all queued commits are uninteresting. * revs->topo_order implies we run sort_in_topological_order(). See the implementation of that method in commit.c. It implies that the full set of commits to order is in the given commit_list. These two methods imply that a 'git rev-list --topo-order HEAD' command must walk the entire reachable set of commits _twice_ before returning a single result. If we have a commit-graph file with generation numbers computed, then there is a better way. This patch introduces some necessary logic redirection when we are in this situation. In v2.18.0, the commit-graph file contains zero-valued bytes in the positions where the generation number is stored in v2.19.0 and later. Thus, we use generation_numbers_enabled() to check if the commit-graph is available and has non-zero generation numbers. When setting revs->limited only because revs->topo_order is true, only do so if generation numbers are not available. There is no reason to use the new logic as it will behave similarly when all generation numbers are INFINITY or ZERO. In prepare_revision_walk(), if we have revs->topo_order but not revs->limited, then we trigger the new logic. It breaks the logic into three pieces, to fit with the existing framework: 1. init_topo_walk() fills a new struct topo_walk_info in the rev_info struct. We use the presence of this struct as a signal to use the new methods during our walk. In this patch, this method simply calls limit_list() and sort_in_topological_order(). In the future, this method will set up a new data structure to perform that logic in-line. 2. next_topo_commit() provides get_revision_1() with the next topo- ordered commit in the list. Currently, this simply pops the commit from revs->commits. 3. expand_topo_walk() provides get_revision_1() with a way to signal walking beyond the latest commit. Currently, this calls add_parents_to_list() exactly like the old logic. While this commit presents method redirection for performing the exact same logic as before, it allows the next commit to focus only on the new logic. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:20 +00:00
if (!revs->ignore_missing_links)
die("Failed to traverse parents of commit %s",
oid_to_hex(&commit->object.oid));
}
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
count_topo_walked++;
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
for (p = commit->parents; p; p = p->next) {
struct commit *parent = p->item;
int *pi;
timestamp_t generation;
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
if (parent->object.flags & UNINTERESTING)
continue;
if (repo_parse_commit_gently(revs->repo, parent, 1) < 0)
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
continue;
generation = commit_graph_generation(parent);
if (generation < info->min_generation) {
info->min_generation = generation;
revision.c: generation-based topo-order algorithm The current --topo-order algorithm requires walking all reachable commits up front, topo-sorting them, all before outputting the first value. This patch introduces a new algorithm which uses stored generation numbers to incrementally walk in topo-order, outputting commits as we go. This can dramatically reduce the computation time to write a fixed number of commits, such as when limiting with "-n <N>" or filling the first page of a pager. When running a command like 'git rev-list --topo-order HEAD', Git performed the following steps: 1. Run limit_list(), which parses all reachable commits, adds them to a linked list, and distributes UNINTERESTING flags. If all unprocessed commits are UNINTERESTING, then it may terminate without walking all reachable commits. This does not occur if we do not specify UNINTERESTING commits. 2. Run sort_in_topological_order(), which is an implementation of Kahn's algorithm. It first iterates through the entire set of important commits and computes the in-degree of each (plus one, as we use 'zero' as a special value here). Then, we walk the commits in priority order, adding them to the priority queue if and only if their in-degree is one. As we remove commits from this priority queue, we decrement the in-degree of their parents. 3. While we are peeling commits for output, get_revision_1() uses pop_commit on the full list of commits computed by sort_in_topological_order(). In the new algorithm, these three steps correspond to three different commit walks. We run these walks simultaneously, and advance each only as far as necessary to satisfy the requirements of the 'higher order' walk. We know when we can pause each walk by using generation numbers from the commit- graph feature. Recall that the generation number of a commit satisfies: * If the commit has at least one parent, then the generation number is one more than the maximum generation number among its parents. * If the commit has no parent, then the generation number is one. There are two special generation numbers: * GENERATION_NUMBER_INFINITY: this value is 0xffffffff and indicates that the commit is not stored in the commit-graph and the generation number was not previously calculated. * GENERATION_NUMBER_ZERO: this value (0) is a special indicator to say that the commit-graph was generated by a version of Git that does not compute generation numbers (such as v2.18.0). Since we use generation_numbers_enabled() before using the new algorithm, we do not need to worry about GENERATION_NUMBER_ZERO. However, the existence of GENERATION_NUMBER_INFINITY implies the following weaker statement than the usual we expect from generation numbers: If A and B are commits with generation numbers gen(A) and gen(B) and gen(A) < gen(B), then A cannot reach B. Thus, we will walk in each of our stages until the "maximum unexpanded generation number" is strictly lower than the generation number of a commit we are about to use. The walks are as follows: 1. EXPLORE: using the explore_queue priority queue (ordered by maximizing the generation number), parse each reachable commit until all commits in the queue have generation number strictly lower than needed. During this walk, update the UNINTERESTING flags as necessary. 2. INDEGREE: using the indegree_queue priority queue (ordered by maximizing the generation number), add one to the in- degree of each parent for each commit that is walked. Since we walk in order of decreasing generation number, we know that discovering an in-degree value of 0 means the value for that commit was not initialized, so should be initialized to two. (Recall that in-degree value "1" is what we use to say a commit is ready for output.) As we iterate the parents of a commit during this walk, ensure the EXPLORE walk has walked beyond their generation numbers. 3. TOPO: using the topo_queue priority queue (ordered based on the sort_order given, which could be commit-date, author- date, or typical topo-order which treats the queue as a LIFO stack), remove a commit from the queue and decrement the in-degree of each parent. If a parent has an in-degree of one, then we add it to the topo_queue. Before we decrement the in-degree, however, ensure the INDEGREE walk has walked beyond that generation number. The implementations of these walks are in the following methods: * explore_walk_step and explore_to_depth * indegree_walk_step and compute_indegrees_to_depth * next_topo_commit and expand_topo_walk These methods have some patterns that may seem strange at first, but they are probably carry-overs from their equivalents in limit_list and sort_in_topological_order. One thing that is missing from this implementation is a proper way to stop walking when the entire queue is UNINTERESTING, so this implementation is not enabled by comparisions, such as in 'git rev-list --topo-order A..B'. This can be updated in the future. In my local testing, I used the following Git commands on the Linux repository in three modes: HEAD~1 with no commit-graph, HEAD~1 with a commit-graph, and HEAD with a commit-graph. This allows comparing the benefits we get from parsing commits from the commit-graph and then again the benefits we get by restricting the set of commits we walk. Test: git rev-list --topo-order -100 HEAD HEAD~1, no commit-graph: 6.80 s HEAD~1, w/ commit-graph: 0.77 s HEAD, w/ commit-graph: 0.02 s Test: git rev-list --topo-order -100 HEAD -- tools HEAD~1, no commit-graph: 9.63 s HEAD~1, w/ commit-graph: 6.06 s HEAD, w/ commit-graph: 0.06 s This speedup is due to a few things. First, the new generation- number-enabled algorithm walks commits on order of the number of results output (subject to some branching structure expectations). Since we limit to 100 results, we are running a query similar to filling a single page of results. Second, when specifying a path, we must parse the root tree object for each commit we walk. The previous benefits from the commit-graph are entirely from reading the commit-graph instead of parsing commits. Since we need to parse trees for the same number of commits as before, we slow down significantly from the non-path-based query. For the test above, I specifically selected a path that is changed frequently, including by merge commits. A less-frequently-changed path (such as 'README') has similar end-to-end time since we need to walk the same number of commits (before determining we do not have 100 hits). However, get the benefit that the output is presented to the user as it is discovered, much the same as a normal 'git log' command (no '--topo-order'). This is an improved user experience, even if the command has the same runtime. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:22 +00:00
compute_indegrees_to_depth(revs, info->min_generation);
}
pi = indegree_slab_at(&info->indegree, parent);
(*pi)--;
if (*pi == 1)
prio_queue_put(&info->topo_queue, parent);
if (revs->first_parent_only)
return;
}
revision.c: begin refactoring --topo-order logic When running 'git rev-list --topo-order' and its kin, the topo_order setting in struct rev_info implies the limited setting. This means that the following things happen during prepare_revision_walk(): * revs->limited implies we run limit_list() to walk the entire reachable set. There are some short-cuts here, such as if we perform a range query like 'git rev-list COMPARE..HEAD' and we can stop limit_list() when all queued commits are uninteresting. * revs->topo_order implies we run sort_in_topological_order(). See the implementation of that method in commit.c. It implies that the full set of commits to order is in the given commit_list. These two methods imply that a 'git rev-list --topo-order HEAD' command must walk the entire reachable set of commits _twice_ before returning a single result. If we have a commit-graph file with generation numbers computed, then there is a better way. This patch introduces some necessary logic redirection when we are in this situation. In v2.18.0, the commit-graph file contains zero-valued bytes in the positions where the generation number is stored in v2.19.0 and later. Thus, we use generation_numbers_enabled() to check if the commit-graph is available and has non-zero generation numbers. When setting revs->limited only because revs->topo_order is true, only do so if generation numbers are not available. There is no reason to use the new logic as it will behave similarly when all generation numbers are INFINITY or ZERO. In prepare_revision_walk(), if we have revs->topo_order but not revs->limited, then we trigger the new logic. It breaks the logic into three pieces, to fit with the existing framework: 1. init_topo_walk() fills a new struct topo_walk_info in the rev_info struct. We use the presence of this struct as a signal to use the new methods during our walk. In this patch, this method simply calls limit_list() and sort_in_topological_order(). In the future, this method will set up a new data structure to perform that logic in-line. 2. next_topo_commit() provides get_revision_1() with the next topo- ordered commit in the list. Currently, this simply pops the commit from revs->commits. 3. expand_topo_walk() provides get_revision_1() with a way to signal walking beyond the latest commit. Currently, this calls add_parents_to_list() exactly like the old logic. While this commit presents method redirection for performing the exact same logic as before, it allows the next commit to focus only on the new logic. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:20 +00:00
}
int prepare_revision_walk(struct rev_info *revs)
{
int i;
struct object_array old_pending;
struct commit_list **next = &revs->commits;
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
memcpy(&old_pending, &revs->pending, sizeof(old_pending));
Add "named object array" concept We've had this notion of a "object_list" for a long time, which eventually grew a "name" member because some users (notably git-rev-list) wanted to name each object as it is generated. That object_list is great for some things, but it isn't all that wonderful for others, and the "name" member is generally not used by everybody. This patch splits the users of the object_list array up into two: the traditional list users, who want the list-like format, and who don't actually use or want the name. And another class of users that really used the list as an extensible array, and generally wanted to name the objects. The patch is fairly straightforward, but it's also biggish. Most of it really just cleans things up: switching the revision parsing and listing over to the array makes things like the builtin-diff usage much simpler (we now see exactly how many members the array has, and we don't get the objects reversed from the order they were on the command line). One of the main reasons for doing this at all is that the malloc overhead of the simple object list was actually pretty high, and the array is just a lot denser. So this patch brings down memory usage by git-rev-list by just under 3% (on top of all the other memory use optimizations) on the mozilla archive. It does add more lines than it removes, and more importantly, it adds a whole new infrastructure for maintaining lists of objects, but on the other hand, the new dynamic array code is pretty obvious. The change to builtin-diff-tree.c shows a fairly good example of why an array interface is sometimes more natural, and just much simpler for everybody. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-06-20 00:42:35 +00:00
revs->pending.nr = 0;
revs->pending.alloc = 0;
revs->pending.objects = NULL;
for (i = 0; i < old_pending.nr; i++) {
struct object_array_entry *e = old_pending.objects + i;
traverse_commit_list: support pending blobs/trees with paths When we call traverse_commit_list, we may have trees and blobs in the pending array. As we process these, we pass the "name" field from the pending entry as the path of the object within the tree (which then becomes the root path if we recurse into subtrees). When we set up the traversal in prepare_revision_walk, though, the "name" field of any pending trees and blobs is likely to be the ref at which we found the object. We would not want to make this part of the path (e.g., doing so would make "git rev-list --objects v2.6.11-tree" in linux.git show paths like "v2.6.11-tree/Makefile", which is nonsensical). Therefore prepare_revision_walk sets the name field of each pending tree and blobs to the empty string. However, this leaves no room for a caller who does know the correct path of a pending object to propagate that information to the revision walker. We can fix this by making two related changes: 1. Use the "path" field as the path instead of the "name" field in traverse_commit_list. If the path is not set, default to "" (which is what we always ended up with in the current code, because of prepare_revision_walk). 2. In prepare_revision_walk, make a complete copy of the entry. This makes the path field available to the walker (if there is one), solving our problem. Leaving the name field intact is now OK, as we do not use it as a path due to point (1) above (and we can use it to make more meaningful error messages if we want). We also make the original "mode" field available to the walker, though it does not actually use it. Note that we still re-add the pending objects and free the old ones (so we may strdup the path and name only to free the old ones). This could be made more efficient by simply copying the object_array entries that we are keeping. However, that would require more restructuring of the code, and is not done here. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-15 22:43:19 +00:00
struct commit *commit = handle_commit(revs, e);
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
if (commit) {
if (!(commit->object.flags & SEEN)) {
commit->object.flags |= SEEN;
next = commit_list_append(commit, next);
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
}
}
}
object_array_clear(&old_pending);
Common option parsing for "git log --diff" and friends This basically does a few things that are sadly somewhat interdependent, and nontrivial to split out - get rid of "struct log_tree_opt" The fields in "log_tree_opt" are moved into "struct rev_info", and all users of log_tree_opt are changed to use the rev_info struct instead. - add the parsing for the log_tree_opt arguments to "setup_revision()" - make setup_revision set a flag (revs->diff) if the diff-related arguments were used. This allows "git log" to decide whether it wants to show diffs or not. - make setup_revision() also initialize the diffopt part of rev_info (which we had from before, but we just didn't initialize it) - make setup_revision() do all the "finishing touches" on it all (it will do the proper flag combination logic, and call "diff_setup_done()") Now, that was the easy and straightforward part. The slightly more involved part is that some of the programs that want to use the new-and-improved rev_info parsing don't actually want _commits_, they may want tree'ish arguments instead. That meant that I had to change setup_revision() to parse the arguments not into the "revs->commits" list, but into the "revs->pending_objects" list. Then, when we do "prepare_revision_walk()", we walk that list, and create the sorted commit list from there. This actually cleaned some stuff up, but it's the less obvious part of the patch, and re-organized the "revision.c" logic somewhat. It actually paves the way for splitting argument parsing _entirely_ out of "revision.c", since now the argument parsing really is totally independent of the commit walking: that didn't use to be true, since there was lots of overlap with get_commit_reference() handling etc, now the _only_ overlap is the shared (and trivial) "add_pending_object()" thing. However, I didn't do that file split, just because I wanted the diff itself to be smaller, and show the actual changes more clearly. If this gets accepted, I'll do further cleanups then - that includes the file split, but also using the new infrastructure to do a nicer "git diff" etc. Even in this form, it actually ends up removing more lines than it adds. It's nice to note how simple and straightforward this makes the built-in "git log" command, even though it continues to support all the diff flags too. It doesn't get much simpler that this. I think this is worth merging soonish, because it does allow for future cleanup and even more sharing of code. However, it obviously touches "revision.c", which is subtle. I've tested that it passes all the tests we have, and it passes my "looks sane" detector, but somebody else should also give it a good look-over. [jc: squashed the original and three "oops this too" updates, with another fix-up.] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-04-14 23:52:13 +00:00
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
/* Signal whether we need per-parent treesame decoration */
if (revs->simplify_merges ||
(revs->limited && limiting_can_increase_treesame(revs)))
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
revs->treesame.name = "treesame";
if (revs->exclude_promisor_objects) {
for_each_packed_object(mark_uninteresting, revs,
FOR_EACH_OBJECT_PROMISOR_ONLY);
}
line-log: integrate with changed-path Bloom filters The previous changes to the line-log machinery focused on making the first result appear faster. This was achieved by no longer walking the entire commit history before returning the early results. There is still another way to improve the performance: walk most commits much faster. Let's use the changed-path Bloom filters to reduce time spent computing diffs. Since the line-log computation requires opening blobs and checking the content-diff, there is still a lot of necessary computation that cannot be replaced with changed-path Bloom filters. The part that we can reduce is most effective when checking the history of a file that is deep in several directories and those directories are modified frequently. In this case, the computation to check if a commit is TREESAME to its first parent takes a large fraction of the time. That is ripe for improvement with changed-path Bloom filters. We must ensure that prepare_to_use_bloom_filters() is called in revision.c so that the bloom_filter_settings are loaded into the struct rev_info from the commit-graph. Of course, some cases are still forbidden, but in the line-log case the pathspec is provided in a different way than normal. Since multiple paths and segments could be requested, we compute the struct bloom_key data dynamically during the commit walk. This could likely be improved, but adds code complexity that is not valuable at this time. There are two cases to care about: merge commits and "ordinary" commits. Merge commits have multiple parents, but if we are TREESAME to our first parent in every range, then pass the blame for all ranges to the first parent. Ordinary commits have the same condition, but each is done slightly differently in the process_ranges_[merge|ordinary]_commit() methods. By checking if the changed-path Bloom filter can guarantee TREESAME, we can avoid that tree-diff cost. If the filter says "probably changed", then we need to run the tree-diff and then the blob-diff if there was a real edit. The Linux kernel repository is a good testing ground for the performance improvements claimed here. There are two different cases to test. The first is the "entire history" case, where we output the entire history to /dev/null to see how long it would take to compute the full line-log history. The second is the "first result" case, where we find how long it takes to show the first value, which is an indicator of how quickly a user would see responses when waiting at a terminal. To test, I selected the paths that were changed most frequently in the top 10,000 commits using this command (stolen from StackOverflow [1]): git log --pretty=format: --name-only -n 10000 | sort | \ uniq -c | sort -rg | head -10 which results in 121 MAINTAINERS 63 fs/namei.c 60 arch/x86/kvm/cpuid.c 59 fs/io_uring.c 58 arch/x86/kvm/vmx/vmx.c 51 arch/x86/kvm/x86.c 45 arch/x86/kvm/svm.c 42 fs/btrfs/disk-io.c 42 Documentation/scsi/index.rst (along with a bogus first result). It appears that the path arch/x86/kvm/svm.c was renamed, so we ignore that entry. This leaves the following results for the real command time: | | Entire History | First Result | | Path | Before | After | Before | After | |------------------------------|--------|--------|--------|--------| | MAINTAINERS | 4.26 s | 3.87 s | 0.41 s | 0.39 s | | fs/namei.c | 1.99 s | 0.99 s | 0.42 s | 0.21 s | | arch/x86/kvm/cpuid.c | 5.28 s | 1.12 s | 0.16 s | 0.09 s | | fs/io_uring.c | 4.34 s | 0.99 s | 0.94 s | 0.27 s | | arch/x86/kvm/vmx/vmx.c | 5.01 s | 1.34 s | 0.21 s | 0.12 s | | arch/x86/kvm/x86.c | 2.24 s | 1.18 s | 0.21 s | 0.14 s | | fs/btrfs/disk-io.c | 1.82 s | 1.01 s | 0.06 s | 0.05 s | | Documentation/scsi/index.rst | 3.30 s | 0.89 s | 1.46 s | 0.03 s | It is worth noting that the least speedup comes for the MAINTAINERS file which is * edited frequently, * low in the directory heirarchy, and * quite a large file. All of those points lead to spending more time doing the blob diff and less time doing the tree diff. Still, we see some improvement in that case and significant improvement in other cases. A 2-4x speedup is likely the more typical case as opposed to the small 5% change for that file. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-11 11:56:19 +00:00
if (!revs->reflog_info)
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
prepare_to_use_bloom_filter(revs);
if (!revs->unsorted_input)
commit_list_sort_by_date(&revs->commits);
if (revs->no_walk)
return 0;
revision.c: begin refactoring --topo-order logic When running 'git rev-list --topo-order' and its kin, the topo_order setting in struct rev_info implies the limited setting. This means that the following things happen during prepare_revision_walk(): * revs->limited implies we run limit_list() to walk the entire reachable set. There are some short-cuts here, such as if we perform a range query like 'git rev-list COMPARE..HEAD' and we can stop limit_list() when all queued commits are uninteresting. * revs->topo_order implies we run sort_in_topological_order(). See the implementation of that method in commit.c. It implies that the full set of commits to order is in the given commit_list. These two methods imply that a 'git rev-list --topo-order HEAD' command must walk the entire reachable set of commits _twice_ before returning a single result. If we have a commit-graph file with generation numbers computed, then there is a better way. This patch introduces some necessary logic redirection when we are in this situation. In v2.18.0, the commit-graph file contains zero-valued bytes in the positions where the generation number is stored in v2.19.0 and later. Thus, we use generation_numbers_enabled() to check if the commit-graph is available and has non-zero generation numbers. When setting revs->limited only because revs->topo_order is true, only do so if generation numbers are not available. There is no reason to use the new logic as it will behave similarly when all generation numbers are INFINITY or ZERO. In prepare_revision_walk(), if we have revs->topo_order but not revs->limited, then we trigger the new logic. It breaks the logic into three pieces, to fit with the existing framework: 1. init_topo_walk() fills a new struct topo_walk_info in the rev_info struct. We use the presence of this struct as a signal to use the new methods during our walk. In this patch, this method simply calls limit_list() and sort_in_topological_order(). In the future, this method will set up a new data structure to perform that logic in-line. 2. next_topo_commit() provides get_revision_1() with the next topo- ordered commit in the list. Currently, this simply pops the commit from revs->commits. 3. expand_topo_walk() provides get_revision_1() with a way to signal walking beyond the latest commit. Currently, this calls add_parents_to_list() exactly like the old logic. While this commit presents method redirection for performing the exact same logic as before, it allows the next commit to focus only on the new logic. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:20 +00:00
if (revs->limited) {
if (limit_list(revs) < 0)
return -1;
revision.c: begin refactoring --topo-order logic When running 'git rev-list --topo-order' and its kin, the topo_order setting in struct rev_info implies the limited setting. This means that the following things happen during prepare_revision_walk(): * revs->limited implies we run limit_list() to walk the entire reachable set. There are some short-cuts here, such as if we perform a range query like 'git rev-list COMPARE..HEAD' and we can stop limit_list() when all queued commits are uninteresting. * revs->topo_order implies we run sort_in_topological_order(). See the implementation of that method in commit.c. It implies that the full set of commits to order is in the given commit_list. These two methods imply that a 'git rev-list --topo-order HEAD' command must walk the entire reachable set of commits _twice_ before returning a single result. If we have a commit-graph file with generation numbers computed, then there is a better way. This patch introduces some necessary logic redirection when we are in this situation. In v2.18.0, the commit-graph file contains zero-valued bytes in the positions where the generation number is stored in v2.19.0 and later. Thus, we use generation_numbers_enabled() to check if the commit-graph is available and has non-zero generation numbers. When setting revs->limited only because revs->topo_order is true, only do so if generation numbers are not available. There is no reason to use the new logic as it will behave similarly when all generation numbers are INFINITY or ZERO. In prepare_revision_walk(), if we have revs->topo_order but not revs->limited, then we trigger the new logic. It breaks the logic into three pieces, to fit with the existing framework: 1. init_topo_walk() fills a new struct topo_walk_info in the rev_info struct. We use the presence of this struct as a signal to use the new methods during our walk. In this patch, this method simply calls limit_list() and sort_in_topological_order(). In the future, this method will set up a new data structure to perform that logic in-line. 2. next_topo_commit() provides get_revision_1() with the next topo- ordered commit in the list. Currently, this simply pops the commit from revs->commits. 3. expand_topo_walk() provides get_revision_1() with a way to signal walking beyond the latest commit. Currently, this calls add_parents_to_list() exactly like the old logic. While this commit presents method redirection for performing the exact same logic as before, it allows the next commit to focus only on the new logic. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:20 +00:00
if (revs->topo_order)
sort_in_topological_order(&revs->commits, revs->sort_order);
} else if (revs->topo_order)
init_topo_walk(revs);
line-log: more responsive, incremental 'git log -L' The current line-level log implementation performs a preprocessing step in prepare_revision_walk(), during which the line_log_filter() function filters and rewrites history to keep only commits modifying the given line range. This preprocessing affects both responsiveness and correctness: - Git doesn't produce any output during this preprocessing step. Checking whether a commit modified the given line range is somewhat expensive, so depending on the size of the given revision range this preprocessing can result in a significant delay before the first commit is shown. - Limiting the number of displayed commits (e.g. 'git log -3 -L...') doesn't limit the amount of work during preprocessing, because that limit is applied during history traversal. Alas, by that point this expensive preprocessing step has already churned through the whole revision range to find all commits modifying the revision range, even though only a few of them need to be shown. - It rewrites parents, with no way to turn it off. Without the user explicitly requesting parent rewriting any parent object ID shown should be that of the immediate parent, just like in case of a pathspec-limited history traversal without parent rewriting. However, after that preprocessing step rewrote history, the subsequent "regular" history traversal (i.e. get_revision() in a loop) only sees commits modifying the given line range. Consequently, it can only show the object ID of the last ancestor that modified the given line range (which might happen to be the immediate parent, but many-many times it isn't). This patch addresses both the correctness and, at least for the common case, the responsiveness issues by integrating line-level log filtering into the regular revision walking machinery: - Make process_ranges_arbitrary_commit(), the static function in 'line-log.c' deciding whether a commit modifies the given line range, public by removing the static keyword and adding the 'line_log_' prefix, so it can be called from other parts of the revision walking machinery. - If the user didn't explicitly ask for parent rewriting (which, I believe, is the most common case): - Call this now-public function during regular history traversal, namely from get_commit_action() to ignore any commits not modifying the given line range. Note that while this check is relatively expensive, it must be performed before other, much cheaper conditions, because the tracked line range must be adjusted even when the commit will end up being ignored by other conditions. - Skip the line_log_filter() call, i.e. the expensive preprocessing step, in prepare_revision_walk(), because, thanks to the above points, the revision walking machinery is now able to filter out commits not modifying the given line range while traversing history. This way the regular history traversal sees the unmodified history, and is therefore able to print the object ids of the immediate parents of the listed commits. The eliminated preprocessing step can greatly reduce the delay before the first commit is shown, see the numbers below. - However, if the user did explicitly ask for parent rewriting via '--parents' or a similar option, then stick with the current implementation for now, i.e. perform that expensive filtering and history rewriting in the preprocessing step just like we did before, leaving the initial delay as long as it was. I tried to integrate line-level log filtering with parent rewriting into the regular history traversal, but, unfortunately, several subtleties resisted... :) Maybe someday we'll figure out how to do that, but until then at least the simple and common (i.e. without parent rewriting) 'git log -L:func:file' commands can benefit from the reduced delay. This change makes the failing 'parent oids without parent rewriting' test in 't4211-line-log.sh' succeed. The reduced delay is most noticable when there's a commit modifying the line range near the tip of a large-ish revision range: # no parent rewriting requested, no commit-graph present $ time git --no-pager log -L:read_alternate_refs:sha1-file.c -1 v2.23.0 Before: real 0m9.570s user 0m9.494s sys 0m0.076s After: real 0m0.718s user 0m0.674s sys 0m0.044s A significant part of the remaining delay is spent reading and parsing commit objects in limit_list(). With the help of the commit-graph we can eliminate most of that reading and parsing overhead, so here are the timing results of the same command as above, but this time using the commit-graph: Before: real 0m8.874s user 0m8.816s sys 0m0.057s After: real 0m0.107s user 0m0.091s sys 0m0.013s The next patch will further reduce the remaining delay. To be clear: this patch doesn't actually optimize the line-level log, but merely moves most of the work from the preprocessing step to the history traversal, so the commits modifying the line range can be shown as soon as they are processed, and the traversal can be terminated as soon as the given number of commits are shown. Consequently, listing the full history of a line range, potentially all the way to the root commit, will take the same time as before (but at least the user might start reading the output earlier). Furthermore, if the most recent commit modifying the line range is far away from the starting revision, then that initial delay will still be significant. Additional testing by Derrick Stolee: In the Linux kernel repository, the MAINTAINERS file was changed ~3,500 times across the ~915,000 commits. In addition to that edit frequency, the file itself is quite large (~18,700 lines). This means that a significant portion of the computation is taken up by computing the patch-diff of the file. This patch improves the real time it takes to output the first result quite a bit: Command: git log -L 100,200:MAINTAINERS -n 1 >/dev/null Before: 3.88 s After: 0.71 s If we drop the "-n 1" in the command, then there is no change in end-to-end process time. This is because the command still needs to walk the entire commit history, which negates the point of this patch. This is expected. As a note for future reference, the ~4.3 seconds in the old code spends ~2.6 seconds computing the patch-diffs, and the rest of the time is spent walking commits and computing diffs for which paths changed at each commit. The changed-path Bloom filters could improve the end-to-end computation time (i.e. no "-n 1" in the command). Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-11 11:56:17 +00:00
if (revs->line_level_traverse && want_ancestry(revs))
/*
* At the moment we can only do line-level log with parent
* rewriting by performing this expensive pre-filtering step.
* If parent rewriting is not requested, then we rather
* perform the line-level log filtering during the regular
* history traversal.
*/
Implement line-history search (git log -L) This is a rewrite of much of Bo's work, mainly in an effort to split it into smaller, easier to understand routines. The algorithm is built around the struct range_set, which encodes a series of line ranges as intervals [a,b). This is used in two contexts: * A set of lines we are tracking (which will change as we dig through history). * To encode diffs, as pairs of ranges. The main routine is range_set_map_across_diff(). It processes the diff between a commit C and some parent P. It determines which diff hunks are relevant to the ranges tracked in C, and computes the new ranges for P. The algorithm is then simply to process history in topological order from newest to oldest, computing ranges and (partial) diffs. At branch points, we need to merge the ranges we are watching. We will find that many commits do not affect the chosen ranges, and mark them TREESAME (in addition to those already filtered by pathspec limiting). Another pass of history simplification then gets rid of such commits. This is wired as an extra filtering pass in the log machinery. This currently only reduces code duplication, but should allow for other simplifications and options to be used. Finally, we hook a diff printer into the output chain. Ideally we would wire directly into the diff logic, to optionally use features like word diff. However, that will require some major reworking of the diff chain, so we completely replace the output with our own diff for now. As this was a GSoC project, and has quite some history by now, many people have helped. In no particular order, thanks go to Jakub Narebski <jnareb@gmail.com> Jens Lehmann <Jens.Lehmann@web.de> Jonathan Nieder <jrnieder@gmail.com> Junio C Hamano <gitster@pobox.com> Ramsay Jones <ramsay@ramsay1.demon.co.uk> Will Palmer <wmpalmer@gmail.com> Apologies to everyone I forgot. Signed-off-by: Bo Yang <struggleyb.nku@gmail.com> Signed-off-by: Thomas Rast <trast@student.ethz.ch> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-03-28 16:47:32 +00:00
line_log_filter(revs);
revision traversal: show full history with merge simplification The --full-history traversal keeps all merges in addition to non-merge commits that touch paths in the given pathspec. This is useful to view both sides of a merge in a topology like this: A---M---o / / ---O---B even when A and B makes identical change to the given paths. The revision traversal without --full-history aims to come up with the simplest history to explain the final state of the tree, and one of the side branches can be pruned away. The behaviour to keep all merges however is inconvenient if neither A nor B touches the paths we are interested in. --full-history reduces the topology to: ---O---M---o in such a case, without removing M. This adds a post processing phase on top of --full-history traversal to remove needless merges from the resulting history. The idea is to compute, for each commit in the "full history" result set, the commit that should replace it in the simplified history. The commit to replace it in the final history is determined as follows: * In any case, we first figure out the replacement commits of parents of the commit we are looking at. The commit we are looking at is rewritten as if the replacement commits of its original parents are its parents. While doing so, we reduce the redundant parents from the rewritten parent list by not just removing the identical ones, but also removing a parent that is an ancestor of another parent. * After the above parent simplification, if the commit is a root commit, an UNINTERESTING commit, a merge commit, or modifies the paths we are interested in, then the replacement commit of the commit is itself. In other words, such a commit is not dropped from the final result. The first point above essentially means that the history is rewritten in the bottom up direction. We can rewrite the parent list of a commit only after we know how all of its parents are rewritten. This means that the processing needs to happen on the full history (i.e. after limit_list()). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-31 08:17:41 +00:00
if (revs->simplify_merges)
simplify_merges(revs);
if (revs->children.name)
set_children(revs);
revision.c: use Bloom filters to speed up path based revision walks Revision walk will now use Bloom filters for commits to speed up revision walks for a particular path (for computing history for that path), if they are present in the commit-graph file. We load the Bloom filters during the prepare_revision_walk step, currently only when dealing with a single pathspec. Extending it to work with multiple pathspecs can be explored and built on top of this series in the future. While comparing trees in rev_compare_trees(), if the Bloom filter says that the file is not different between the two trees, we don't need to compute the expensive diff. This is where we get our performance gains. The other response of the Bloom filter is '`:maybe', in which case we fall back to the full diff calculation to determine if the path was changed in the commit. We do not try to use Bloom filters when the '--walk-reflogs' option is specified. The '--walk-reflogs' option does not walk the commit ancestry chain like the rest of the options. Incorporating the performance gains when walking reflog entries would add more complexity, and can be explored in a later series. Performance Gains: We tested the performance of `git log -- <path>` on the git repo, the linux and some internal large repos, with a variety of paths of varying depths. On the git and linux repos: - we observed a 2x to 5x speed up. On a large internal repo with files seated 6-10 levels deep in the tree: - we observed 10x to 20x speed ups, with some paths going up to 28 times faster. Helped-by: Derrick Stolee <dstolee@microsoft.com Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06 16:59:52 +00:00
return 0;
}
revision: use a prio_queue to hold rewritten parents This patch fixes a quadratic list insertion in rewrite_one() when pathspec limiting is combined with --parents. What happens is something like this: 1. We see that some commit X touches the path, so we try to rewrite its parents. 2. rewrite_one() loops forever, rewriting parents, until it finds a relevant parent (or hits the root and decides there are none). The heavy lifting is done by process_parent(), which uses try_to_simplify_commit() to drop parents. 3. process_parent() puts any intermediate parents into the &revs->commits list, inserting by commit date as usual. So if commit X is recent, and then there's a large chunk of history that doesn't touch the path, we may add a lot of commits to &revs->commits. And insertion by commit date is O(n) in the worst case, making the whole thing quadratic. We tried to deal with this long ago in fce87ae538 (Fix quadratic performance in rewrite_one., 2008-07-12). In that scheme, we cache the oldest commit in the list; if the new commit to be added is older, we can start our linear traversal there. This often works well in practice because parents are older than their descendants, and thus we tend to add older and older commits as we traverse. But this isn't guaranteed, and in fact there's a simple case where it is not: merges. Imagine we look at the first parent of a merge and see a very old commit (let's say 3 years old). And on the second parent, as we go back 3 years in history, we might have many commits. That one first-parent commit has polluted our oldest-commit cache; it will remain the oldest while we traverse a huge chunk of history, during which we have to fall back to the slow, linear method of adding to the list. Naively, one might imagine that instead of caching the oldest commit, we'd start at the last-added one. But that just makes some cases faster while making others slower (and indeed, while it made a real-world test case much faster, it does quite poorly in the perf test include here). Fundamentally, these are just heuristics; our worst case is still quadratic, and some cases will approach that. Instead, let's use a data structure with better worst-case performance. Swapping out revs->commits for something else would have repercussions all over the code base, but we can take advantage of one fact: for the rewrite_one() case, nobody actually needs to see those commits in revs->commits until we've finished generating the whole list. That leaves us with two obvious options: 1. We can generate the list _unordered_, which should be O(n), and then sort it afterwards, which would be O(n log n) total. This is "sort-after" below. 2. We can insert the commits into a separate data structure, like a priority queue. This is "prio-queue" below. I expected that sort-after would be the fastest (since it saves us the extra step of copying the items into the linked list), but surprisingly the prio-queue seems to be a bit faster. Here are timings for the new p0001.6 for all three techniques across a few repositories, as compared to master: master cache-last sort-after prio-queue -------------------------------------------------------------------------------------------- GIT_PERF_REPO=git.git 0.52(0.50+0.02) 0.53(0.51+0.02) +1.9% 0.37(0.33+0.03) -28.8% 0.37(0.32+0.04) -28.8% GIT_PERF_REPO=linux.git 20.81(20.74+0.07) 20.31(20.24+0.07) -2.4% 0.94(0.86+0.07) -95.5% 0.91(0.82+0.09) -95.6% GIT_PERF_REPO=llvm-project.git 83.67(83.57+0.09) 4.23(4.15+0.08) -94.9% 3.21(3.15+0.06) -96.2% 2.98(2.91+0.07) -96.4% A few items to note: - the cache-list tweak does improve the bad case for llvm-project.git that started my digging into this problem. But it performs terribly on linux.git, barely helping at all. - the sort-after and prio-queue techniques work well. They approach the timing for running without --parents at all, which is what you'd expect (see below for more data). - prio-queue just barely outperforms sort-after. As I said, I'm not really sure why this is the case, but it is. You can see it even more prominently in this real-world case on llvm-project.git: git rev-list --parents 07ef786652e7 -- llvm/test/CodeGen/Generic/bswap.ll where prio-queue routinely outperforms sort-after by about 7%. One guess is that the prio-queue may just be more efficient because it uses a compact array. There are three new perf tests: - "rev-list --parents" gives us a baseline for running with --parents. This isn't sped up meaningfully here, because the bad case is triggered only with simplification. But it's good to make sure we don't screw it up (now, or in the future). - "rev-list -- dummy" gives us a baseline for just traversing with pathspec limiting. This gives a lower bound for the next test (and it's also a good thing for us to be checking in general for regressions, since we don't seem to have any existing tests). - "rev-list --parents -- dummy" shows off the problem (and our fix) Here are the timings for those three on llvm-project.git, before and after the fix: Test master prio-queue ------------------------------------------------------------------------------ 0001.3: rev-list --parents 2.24(2.12+0.12) 2.22(2.11+0.11) -0.9% 0001.5: rev-list -- dummy 2.89(2.82+0.07) 2.92(2.89+0.03) +1.0% 0001.6: rev-list --parents -- dummy 83.67(83.57+0.09) 2.98(2.91+0.07) -96.4% Changes in the first two are basically noise, and you can see we approach our lower bound in the final one. Note that we can't fully get rid of the list argument from process_parents(). Other callers do have lists, and it would be hard to convert them. They also don't seem to have this problem (probably because they actually remove items from the list as they loop, meaning it doesn't grow so large in the first place). So this basically just drops the "cache_ptr" parameter (which was used only by the one caller we're fixing here) and replaces it with a prio_queue. Callers are free to use either data structure, depending on what they're prepared to handle. Reported-by: Björn Pettersson A <bjorn.a.pettersson@ericsson.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-04 01:41:09 +00:00
static enum rewrite_result rewrite_one_1(struct rev_info *revs,
struct commit **pp,
struct prio_queue *queue)
{
for (;;) {
struct commit *p = *pp;
if (!revs->limited)
revision: use a prio_queue to hold rewritten parents This patch fixes a quadratic list insertion in rewrite_one() when pathspec limiting is combined with --parents. What happens is something like this: 1. We see that some commit X touches the path, so we try to rewrite its parents. 2. rewrite_one() loops forever, rewriting parents, until it finds a relevant parent (or hits the root and decides there are none). The heavy lifting is done by process_parent(), which uses try_to_simplify_commit() to drop parents. 3. process_parent() puts any intermediate parents into the &revs->commits list, inserting by commit date as usual. So if commit X is recent, and then there's a large chunk of history that doesn't touch the path, we may add a lot of commits to &revs->commits. And insertion by commit date is O(n) in the worst case, making the whole thing quadratic. We tried to deal with this long ago in fce87ae538 (Fix quadratic performance in rewrite_one., 2008-07-12). In that scheme, we cache the oldest commit in the list; if the new commit to be added is older, we can start our linear traversal there. This often works well in practice because parents are older than their descendants, and thus we tend to add older and older commits as we traverse. But this isn't guaranteed, and in fact there's a simple case where it is not: merges. Imagine we look at the first parent of a merge and see a very old commit (let's say 3 years old). And on the second parent, as we go back 3 years in history, we might have many commits. That one first-parent commit has polluted our oldest-commit cache; it will remain the oldest while we traverse a huge chunk of history, during which we have to fall back to the slow, linear method of adding to the list. Naively, one might imagine that instead of caching the oldest commit, we'd start at the last-added one. But that just makes some cases faster while making others slower (and indeed, while it made a real-world test case much faster, it does quite poorly in the perf test include here). Fundamentally, these are just heuristics; our worst case is still quadratic, and some cases will approach that. Instead, let's use a data structure with better worst-case performance. Swapping out revs->commits for something else would have repercussions all over the code base, but we can take advantage of one fact: for the rewrite_one() case, nobody actually needs to see those commits in revs->commits until we've finished generating the whole list. That leaves us with two obvious options: 1. We can generate the list _unordered_, which should be O(n), and then sort it afterwards, which would be O(n log n) total. This is "sort-after" below. 2. We can insert the commits into a separate data structure, like a priority queue. This is "prio-queue" below. I expected that sort-after would be the fastest (since it saves us the extra step of copying the items into the linked list), but surprisingly the prio-queue seems to be a bit faster. Here are timings for the new p0001.6 for all three techniques across a few repositories, as compared to master: master cache-last sort-after prio-queue -------------------------------------------------------------------------------------------- GIT_PERF_REPO=git.git 0.52(0.50+0.02) 0.53(0.51+0.02) +1.9% 0.37(0.33+0.03) -28.8% 0.37(0.32+0.04) -28.8% GIT_PERF_REPO=linux.git 20.81(20.74+0.07) 20.31(20.24+0.07) -2.4% 0.94(0.86+0.07) -95.5% 0.91(0.82+0.09) -95.6% GIT_PERF_REPO=llvm-project.git 83.67(83.57+0.09) 4.23(4.15+0.08) -94.9% 3.21(3.15+0.06) -96.2% 2.98(2.91+0.07) -96.4% A few items to note: - the cache-list tweak does improve the bad case for llvm-project.git that started my digging into this problem. But it performs terribly on linux.git, barely helping at all. - the sort-after and prio-queue techniques work well. They approach the timing for running without --parents at all, which is what you'd expect (see below for more data). - prio-queue just barely outperforms sort-after. As I said, I'm not really sure why this is the case, but it is. You can see it even more prominently in this real-world case on llvm-project.git: git rev-list --parents 07ef786652e7 -- llvm/test/CodeGen/Generic/bswap.ll where prio-queue routinely outperforms sort-after by about 7%. One guess is that the prio-queue may just be more efficient because it uses a compact array. There are three new perf tests: - "rev-list --parents" gives us a baseline for running with --parents. This isn't sped up meaningfully here, because the bad case is triggered only with simplification. But it's good to make sure we don't screw it up (now, or in the future). - "rev-list -- dummy" gives us a baseline for just traversing with pathspec limiting. This gives a lower bound for the next test (and it's also a good thing for us to be checking in general for regressions, since we don't seem to have any existing tests). - "rev-list --parents -- dummy" shows off the problem (and our fix) Here are the timings for those three on llvm-project.git, before and after the fix: Test master prio-queue ------------------------------------------------------------------------------ 0001.3: rev-list --parents 2.24(2.12+0.12) 2.22(2.11+0.11) -0.9% 0001.5: rev-list -- dummy 2.89(2.82+0.07) 2.92(2.89+0.03) +1.0% 0001.6: rev-list --parents -- dummy 83.67(83.57+0.09) 2.98(2.91+0.07) -96.4% Changes in the first two are basically noise, and you can see we approach our lower bound in the final one. Note that we can't fully get rid of the list argument from process_parents(). Other callers do have lists, and it would be hard to convert them. They also don't seem to have this problem (probably because they actually remove items from the list as they loop, meaning it doesn't grow so large in the first place). So this basically just drops the "cache_ptr" parameter (which was used only by the one caller we're fixing here) and replaces it with a prio_queue. Callers are free to use either data structure, depending on what they're prepared to handle. Reported-by: Björn Pettersson A <bjorn.a.pettersson@ericsson.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-04 01:41:09 +00:00
if (process_parents(revs, p, NULL, queue) < 0)
return rewrite_one_error;
if (p->object.flags & UNINTERESTING)
return rewrite_one_ok;
if (!(p->object.flags & TREESAME))
return rewrite_one_ok;
if (!p->parents)
return rewrite_one_noparents;
if ((p = one_relevant_parent(revs, p->parents)) == NULL)
return rewrite_one_ok;
*pp = p;
}
}
revision: use a prio_queue to hold rewritten parents This patch fixes a quadratic list insertion in rewrite_one() when pathspec limiting is combined with --parents. What happens is something like this: 1. We see that some commit X touches the path, so we try to rewrite its parents. 2. rewrite_one() loops forever, rewriting parents, until it finds a relevant parent (or hits the root and decides there are none). The heavy lifting is done by process_parent(), which uses try_to_simplify_commit() to drop parents. 3. process_parent() puts any intermediate parents into the &revs->commits list, inserting by commit date as usual. So if commit X is recent, and then there's a large chunk of history that doesn't touch the path, we may add a lot of commits to &revs->commits. And insertion by commit date is O(n) in the worst case, making the whole thing quadratic. We tried to deal with this long ago in fce87ae538 (Fix quadratic performance in rewrite_one., 2008-07-12). In that scheme, we cache the oldest commit in the list; if the new commit to be added is older, we can start our linear traversal there. This often works well in practice because parents are older than their descendants, and thus we tend to add older and older commits as we traverse. But this isn't guaranteed, and in fact there's a simple case where it is not: merges. Imagine we look at the first parent of a merge and see a very old commit (let's say 3 years old). And on the second parent, as we go back 3 years in history, we might have many commits. That one first-parent commit has polluted our oldest-commit cache; it will remain the oldest while we traverse a huge chunk of history, during which we have to fall back to the slow, linear method of adding to the list. Naively, one might imagine that instead of caching the oldest commit, we'd start at the last-added one. But that just makes some cases faster while making others slower (and indeed, while it made a real-world test case much faster, it does quite poorly in the perf test include here). Fundamentally, these are just heuristics; our worst case is still quadratic, and some cases will approach that. Instead, let's use a data structure with better worst-case performance. Swapping out revs->commits for something else would have repercussions all over the code base, but we can take advantage of one fact: for the rewrite_one() case, nobody actually needs to see those commits in revs->commits until we've finished generating the whole list. That leaves us with two obvious options: 1. We can generate the list _unordered_, which should be O(n), and then sort it afterwards, which would be O(n log n) total. This is "sort-after" below. 2. We can insert the commits into a separate data structure, like a priority queue. This is "prio-queue" below. I expected that sort-after would be the fastest (since it saves us the extra step of copying the items into the linked list), but surprisingly the prio-queue seems to be a bit faster. Here are timings for the new p0001.6 for all three techniques across a few repositories, as compared to master: master cache-last sort-after prio-queue -------------------------------------------------------------------------------------------- GIT_PERF_REPO=git.git 0.52(0.50+0.02) 0.53(0.51+0.02) +1.9% 0.37(0.33+0.03) -28.8% 0.37(0.32+0.04) -28.8% GIT_PERF_REPO=linux.git 20.81(20.74+0.07) 20.31(20.24+0.07) -2.4% 0.94(0.86+0.07) -95.5% 0.91(0.82+0.09) -95.6% GIT_PERF_REPO=llvm-project.git 83.67(83.57+0.09) 4.23(4.15+0.08) -94.9% 3.21(3.15+0.06) -96.2% 2.98(2.91+0.07) -96.4% A few items to note: - the cache-list tweak does improve the bad case for llvm-project.git that started my digging into this problem. But it performs terribly on linux.git, barely helping at all. - the sort-after and prio-queue techniques work well. They approach the timing for running without --parents at all, which is what you'd expect (see below for more data). - prio-queue just barely outperforms sort-after. As I said, I'm not really sure why this is the case, but it is. You can see it even more prominently in this real-world case on llvm-project.git: git rev-list --parents 07ef786652e7 -- llvm/test/CodeGen/Generic/bswap.ll where prio-queue routinely outperforms sort-after by about 7%. One guess is that the prio-queue may just be more efficient because it uses a compact array. There are three new perf tests: - "rev-list --parents" gives us a baseline for running with --parents. This isn't sped up meaningfully here, because the bad case is triggered only with simplification. But it's good to make sure we don't screw it up (now, or in the future). - "rev-list -- dummy" gives us a baseline for just traversing with pathspec limiting. This gives a lower bound for the next test (and it's also a good thing for us to be checking in general for regressions, since we don't seem to have any existing tests). - "rev-list --parents -- dummy" shows off the problem (and our fix) Here are the timings for those three on llvm-project.git, before and after the fix: Test master prio-queue ------------------------------------------------------------------------------ 0001.3: rev-list --parents 2.24(2.12+0.12) 2.22(2.11+0.11) -0.9% 0001.5: rev-list -- dummy 2.89(2.82+0.07) 2.92(2.89+0.03) +1.0% 0001.6: rev-list --parents -- dummy 83.67(83.57+0.09) 2.98(2.91+0.07) -96.4% Changes in the first two are basically noise, and you can see we approach our lower bound in the final one. Note that we can't fully get rid of the list argument from process_parents(). Other callers do have lists, and it would be hard to convert them. They also don't seem to have this problem (probably because they actually remove items from the list as they loop, meaning it doesn't grow so large in the first place). So this basically just drops the "cache_ptr" parameter (which was used only by the one caller we're fixing here) and replaces it with a prio_queue. Callers are free to use either data structure, depending on what they're prepared to handle. Reported-by: Björn Pettersson A <bjorn.a.pettersson@ericsson.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-04 01:41:09 +00:00
static void merge_queue_into_list(struct prio_queue *q, struct commit_list **list)
{
while (q->nr) {
struct commit *item = prio_queue_peek(q);
struct commit_list *p = *list;
if (p && p->item->date >= item->date)
list = &p->next;
else {
p = commit_list_insert(item, list);
list = &p->next; /* skip newly added item */
prio_queue_get(q); /* pop item */
}
}
}
static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
{
struct prio_queue queue = { compare_commits_by_commit_date };
enum rewrite_result ret = rewrite_one_1(revs, pp, &queue);
merge_queue_into_list(&queue, &revs->commits);
clear_prio_queue(&queue);
return ret;
}
int rewrite_parents(struct rev_info *revs, struct commit *commit,
rewrite_parent_fn_t rewrite_parent)
{
struct commit_list **pp = &commit->parents;
while (*pp) {
struct commit_list *parent = *pp;
switch (rewrite_parent(revs, &parent->item)) {
case rewrite_one_ok:
break;
case rewrite_one_noparents:
*pp = parent->next;
continue;
case rewrite_one_error:
return -1;
}
pp = &parent->next;
}
revision.c: Make --full-history consider more merges History simplification previously always treated merges as TREESAME if they were TREESAME to any parent. While this was consistent with the default behaviour, this could be extremely unhelpful when searching detailed history, and could not be overridden. For example, if a merge had ignored a change, as if by "-s ours", then: git log -m -p --full-history -Schange file would successfully locate "change"'s addition but would not locate the merge that resolved against it. Futher, simplify_merges could drop the actual parent that a commit was TREESAME to, leaving it as a normal commit marked TREESAME that isn't actually TREESAME to its remaining parent. Now redefine a commit's TREESAME flag to be true only if a commit is TREESAME to _all_ of its parents. This doesn't affect either the default simplify_history behaviour (because partially TREESAME merges are turned into normal commits), or full-history with parent rewriting (because all merges are output). But it does affect other modes. The clearest difference is that --full-history will show more merges - sufficient to ensure that -m -p --full-history log searches can really explain every change to the file, including those changes' ultimate fate in merges. Also modify simplify_merges to recalculate TREESAME after removing a parent. This is achieved by storing per-parent TREESAME flags on the initial scan, so the combined flag can be easily recomputed. This fixes some t6111 failures, but creates a couple of new ones - we are now showing some merges that don't need to be shown. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-16 15:32:34 +00:00
remove_duplicate_parents(revs, commit);
return 0;
}
static int commit_rewrite_person(struct strbuf *buf, const char *what, struct string_list *mailmap)
{
char *person, *endp;
size_t len, namelen, maillen;
const char *name;
const char *mail;
struct ident_split ident;
person = strstr(buf->buf, what);
if (!person)
return 0;
person += strlen(what);
endp = strchr(person, '\n');
if (!endp)
return 0;
len = endp - person;
if (split_ident_line(&ident, person, len))
return 0;
mail = ident.mail_begin;
maillen = ident.mail_end - ident.mail_begin;
name = ident.name_begin;
namelen = ident.name_end - ident.name_begin;
if (map_user(mailmap, &mail, &maillen, &name, &namelen)) {
struct strbuf namemail = STRBUF_INIT;
strbuf_addf(&namemail, "%.*s <%.*s>",
(int)namelen, name, (int)maillen, mail);
strbuf_splice(buf, ident.name_begin - buf->buf,
ident.mail_end - ident.name_begin + 1,
namemail.buf, namemail.len);
strbuf_release(&namemail);
return 1;
}
return 0;
}
static int commit_match(struct commit *commit, struct rev_info *opt)
{
int retval;
log: re-encode commit messages before grepping If you run "git log --grep=foo", we will run your regex on the literal bytes of the commit message. This can provide confusing results if the commit message is not in the same encoding as your grep expression (or worse, you have commits in multiple encodings, in which case your regex would need to be written to match either encoding). On top of this, we might also be grepping in the commit's notes, which are already re-encoded, potentially leading to grepping in a buffer with mixed encodings concatenated. This is insanity, but most people never noticed, because their terminal and their commit encodings all match. Instead, let's massage the to-be-grepped commit into a standardized encoding. There is not much point in adding a flag for "this is the encoding I expect my grep pattern to match"; the only sane choice is for it to use the log output encoding. That is presumably what the user's terminal is using, and it means that the patterns found by the grep will match the output produced by git. As a bonus, this fixes a potential segfault in commit_match when commit->buffer is NULL, as we now build on logmsg_reencode, which handles reading the commit buffer from disk if necessary. The segfault can be triggered with: git commit -m 'text1' --allow-empty git commit -m 'text2' --allow-empty git log --graph --no-walk --grep 'text2' which arguably does not make any sense (--graph inherently wants a connected history, and by --no-walk the command line is telling us to show discrete points in history without connectivity), and we probably should forbid the combination, but that is a separate issue. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-11 20:59:58 +00:00
const char *encoding;
const char *message;
struct strbuf buf = STRBUF_INIT;
log: re-encode commit messages before grepping If you run "git log --grep=foo", we will run your regex on the literal bytes of the commit message. This can provide confusing results if the commit message is not in the same encoding as your grep expression (or worse, you have commits in multiple encodings, in which case your regex would need to be written to match either encoding). On top of this, we might also be grepping in the commit's notes, which are already re-encoded, potentially leading to grepping in a buffer with mixed encodings concatenated. This is insanity, but most people never noticed, because their terminal and their commit encodings all match. Instead, let's massage the to-be-grepped commit into a standardized encoding. There is not much point in adding a flag for "this is the encoding I expect my grep pattern to match"; the only sane choice is for it to use the log output encoding. That is presumably what the user's terminal is using, and it means that the patterns found by the grep will match the output produced by git. As a bonus, this fixes a potential segfault in commit_match when commit->buffer is NULL, as we now build on logmsg_reencode, which handles reading the commit buffer from disk if necessary. The segfault can be triggered with: git commit -m 'text1' --allow-empty git commit -m 'text2' --allow-empty git log --graph --no-walk --grep 'text2' which arguably does not make any sense (--graph inherently wants a connected history, and by --no-walk the command line is telling us to show discrete points in history without connectivity), and we probably should forbid the combination, but that is a separate issue. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-11 20:59:58 +00:00
if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
return 1;
/* Prepend "fake" headers as needed */
if (opt->grep_filter.use_reflog_filter) {
strbuf_addstr(&buf, "reflog ");
get_reflog_message(&buf, opt->reflog_info);
strbuf_addch(&buf, '\n');
}
log: re-encode commit messages before grepping If you run "git log --grep=foo", we will run your regex on the literal bytes of the commit message. This can provide confusing results if the commit message is not in the same encoding as your grep expression (or worse, you have commits in multiple encodings, in which case your regex would need to be written to match either encoding). On top of this, we might also be grepping in the commit's notes, which are already re-encoded, potentially leading to grepping in a buffer with mixed encodings concatenated. This is insanity, but most people never noticed, because their terminal and their commit encodings all match. Instead, let's massage the to-be-grepped commit into a standardized encoding. There is not much point in adding a flag for "this is the encoding I expect my grep pattern to match"; the only sane choice is for it to use the log output encoding. That is presumably what the user's terminal is using, and it means that the patterns found by the grep will match the output produced by git. As a bonus, this fixes a potential segfault in commit_match when commit->buffer is NULL, as we now build on logmsg_reencode, which handles reading the commit buffer from disk if necessary. The segfault can be triggered with: git commit -m 'text1' --allow-empty git commit -m 'text2' --allow-empty git log --graph --no-walk --grep 'text2' which arguably does not make any sense (--graph inherently wants a connected history, and by --no-walk the command line is telling us to show discrete points in history without connectivity), and we probably should forbid the combination, but that is a separate issue. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-11 20:59:58 +00:00
/*
* We grep in the user's output encoding, under the assumption that it
* is the encoding they are most likely to write their grep pattern
* for. In addition, it means we will match the "notes" encoding below,
* so we will not end up with a buffer that has two different encodings
* in it.
*/
encoding = get_log_output_encoding();
message = logmsg_reencode(commit, NULL, encoding);
log: re-encode commit messages before grepping If you run "git log --grep=foo", we will run your regex on the literal bytes of the commit message. This can provide confusing results if the commit message is not in the same encoding as your grep expression (or worse, you have commits in multiple encodings, in which case your regex would need to be written to match either encoding). On top of this, we might also be grepping in the commit's notes, which are already re-encoded, potentially leading to grepping in a buffer with mixed encodings concatenated. This is insanity, but most people never noticed, because their terminal and their commit encodings all match. Instead, let's massage the to-be-grepped commit into a standardized encoding. There is not much point in adding a flag for "this is the encoding I expect my grep pattern to match"; the only sane choice is for it to use the log output encoding. That is presumably what the user's terminal is using, and it means that the patterns found by the grep will match the output produced by git. As a bonus, this fixes a potential segfault in commit_match when commit->buffer is NULL, as we now build on logmsg_reencode, which handles reading the commit buffer from disk if necessary. The segfault can be triggered with: git commit -m 'text1' --allow-empty git commit -m 'text2' --allow-empty git log --graph --no-walk --grep 'text2' which arguably does not make any sense (--graph inherently wants a connected history, and by --no-walk the command line is telling us to show discrete points in history without connectivity), and we probably should forbid the combination, but that is a separate issue. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-11 20:59:58 +00:00
/* Copy the commit to temporary if we are using "fake" headers */
if (buf.len)
log: re-encode commit messages before grepping If you run "git log --grep=foo", we will run your regex on the literal bytes of the commit message. This can provide confusing results if the commit message is not in the same encoding as your grep expression (or worse, you have commits in multiple encodings, in which case your regex would need to be written to match either encoding). On top of this, we might also be grepping in the commit's notes, which are already re-encoded, potentially leading to grepping in a buffer with mixed encodings concatenated. This is insanity, but most people never noticed, because their terminal and their commit encodings all match. Instead, let's massage the to-be-grepped commit into a standardized encoding. There is not much point in adding a flag for "this is the encoding I expect my grep pattern to match"; the only sane choice is for it to use the log output encoding. That is presumably what the user's terminal is using, and it means that the patterns found by the grep will match the output produced by git. As a bonus, this fixes a potential segfault in commit_match when commit->buffer is NULL, as we now build on logmsg_reencode, which handles reading the commit buffer from disk if necessary. The segfault can be triggered with: git commit -m 'text1' --allow-empty git commit -m 'text2' --allow-empty git log --graph --no-walk --grep 'text2' which arguably does not make any sense (--graph inherently wants a connected history, and by --no-walk the command line is telling us to show discrete points in history without connectivity), and we probably should forbid the combination, but that is a separate issue. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-11 20:59:58 +00:00
strbuf_addstr(&buf, message);
log --use-mailmap: optimize for cases without --author/--committer search When we taught the commit_match() mechanism to pay attention to the new --use-mailmap option, we started to unconditionally copy the commit object to a temporary buffer, just in case we need the author and committer lines updated via the mailmap mechanism, and rewrite author and committer using the mailmap. It turns out that this has a rather unpleasant performance implications. In the linux kernel repository, running $ git log --author='Junio C Hamano' --pretty=short >/dev/null under /usr/bin/time, with and without --use-mailmap (the .mailmap file is 118 entries long, the particular author does not appear in it), cost (with warm cache): [without --use-mailmap] 5.42user 0.26system 0:05.70elapsed 99%CPU (0avgtext+0avgdata 2005936maxresident)k 0inputs+0outputs (0major+137669minor)pagefaults 0swaps [with --use-mailmap] 6.47user 0.30system 0:06.78elapsed 99%CPU (0avgtext+0avgdata 2006288maxresident)k 0inputs+0outputs (0major+137692minor)pagefaults 0swaps which incurs about 20% overhead. The command is doing extra work, so the extra cost may be justified. But it is inexcusable to pay the cost when we do not need author/committer match. In the same repository, $ git log --grep='fix menuconfig on debian lenny' --pretty=short >/dev/null shows very similar numbers as the above: [without --use-mailmap] 5.32user 0.30system 0:05.63elapsed 99%CPU (0avgtext+0avgdata 2005984maxresident)k 0inputs+0outputs (0major+137672minor)pagefaults 0swaps [with --use-mailmap] 6.64user 0.24system 0:06.89elapsed 99%CPU (0avgtext+0avgdata 2006320maxresident)k 0inputs+0outputs (0major+137694minor)pagefaults 0swaps The latter case is an unnecessary performance regression. We may want to _show_ the result with mailmap applied, but we do not have to copy and rewrite the author/committer of all commits we try to match if we do not query for these fields. Trivially optimize this performace regression by limiting the rewrites for only when we are matching with author/committer fields. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-01-08 08:02:49 +00:00
if (opt->grep_filter.header_list && opt->mailmap) {
if (!buf.len)
log: re-encode commit messages before grepping If you run "git log --grep=foo", we will run your regex on the literal bytes of the commit message. This can provide confusing results if the commit message is not in the same encoding as your grep expression (or worse, you have commits in multiple encodings, in which case your regex would need to be written to match either encoding). On top of this, we might also be grepping in the commit's notes, which are already re-encoded, potentially leading to grepping in a buffer with mixed encodings concatenated. This is insanity, but most people never noticed, because their terminal and their commit encodings all match. Instead, let's massage the to-be-grepped commit into a standardized encoding. There is not much point in adding a flag for "this is the encoding I expect my grep pattern to match"; the only sane choice is for it to use the log output encoding. That is presumably what the user's terminal is using, and it means that the patterns found by the grep will match the output produced by git. As a bonus, this fixes a potential segfault in commit_match when commit->buffer is NULL, as we now build on logmsg_reencode, which handles reading the commit buffer from disk if necessary. The segfault can be triggered with: git commit -m 'text1' --allow-empty git commit -m 'text2' --allow-empty git log --graph --no-walk --grep 'text2' which arguably does not make any sense (--graph inherently wants a connected history, and by --no-walk the command line is telling us to show discrete points in history without connectivity), and we probably should forbid the combination, but that is a separate issue. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-11 20:59:58 +00:00
strbuf_addstr(&buf, message);
commit_rewrite_person(&buf, "\nauthor ", opt->mailmap);
commit_rewrite_person(&buf, "\ncommitter ", opt->mailmap);
}
/* Append "fake" message parts as needed */
if (opt->show_notes) {
if (!buf.len)
log: re-encode commit messages before grepping If you run "git log --grep=foo", we will run your regex on the literal bytes of the commit message. This can provide confusing results if the commit message is not in the same encoding as your grep expression (or worse, you have commits in multiple encodings, in which case your regex would need to be written to match either encoding). On top of this, we might also be grepping in the commit's notes, which are already re-encoded, potentially leading to grepping in a buffer with mixed encodings concatenated. This is insanity, but most people never noticed, because their terminal and their commit encodings all match. Instead, let's massage the to-be-grepped commit into a standardized encoding. There is not much point in adding a flag for "this is the encoding I expect my grep pattern to match"; the only sane choice is for it to use the log output encoding. That is presumably what the user's terminal is using, and it means that the patterns found by the grep will match the output produced by git. As a bonus, this fixes a potential segfault in commit_match when commit->buffer is NULL, as we now build on logmsg_reencode, which handles reading the commit buffer from disk if necessary. The segfault can be triggered with: git commit -m 'text1' --allow-empty git commit -m 'text2' --allow-empty git log --graph --no-walk --grep 'text2' which arguably does not make any sense (--graph inherently wants a connected history, and by --no-walk the command line is telling us to show discrete points in history without connectivity), and we probably should forbid the combination, but that is a separate issue. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-11 20:59:58 +00:00
strbuf_addstr(&buf, message);
format_display_notes(&commit->object.oid, &buf, encoding, 1);
}
/*
* Find either in the original commit message, or in the temporary.
* Note that we cast away the constness of "message" here. It is
* const because it may come from the cached commit buffer. That's OK,
* because we know that it is modifiable heap memory, and that while
* grep_buffer may modify it for speed, it will restore any
* changes before returning.
*/
if (buf.len)
retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
else
retval = grep_buffer(&opt->grep_filter,
(char *)message, strlen(message));
strbuf_release(&buf);
unuse_commit_buffer(commit, message);
return retval;
}
log: use true parents for diff even when rewriting When using pathspec filtering in combination with diff-based log output, parent simplification happens before the diff is computed. The diff is therefore against the *simplified* parents. This works okay, arguably by accident, in the normal case: simplification reduces to one parent as long as the commit is TREESAME to it. So the simplified parent of any given commit must have the same tree contents on the filtered paths as its true (unfiltered) parent. However, --full-diff breaks this guarantee, and indeed gives pretty spectacular results when comparing the output of git log --graph --stat ... git log --graph --full-diff --stat ... (--graph internally kicks in parent simplification, much like --parents). To fix it, store a copy of the parent list before simplification (in a slab) whenever --full-diff is in effect. Then use the stored parents instead of the simplified ones in the commit display code paths. The latter do not actually check for --full-diff to avoid duplicated code; they just grab the original parents if save_parents() has not been called for this revision walk. For ordinary commits it should be obvious that this is the right thing to do. Merge commits are a bit subtle. Observe that with default simplification, merge simplification is an all-or-nothing decision: either the merge is TREESAME to one parent and disappears, or it is different from all parents and the parent list remains intact. Redundant parents are not pruned, so the existing code also shows them as a merge. So if we do show a merge commit, the parent list just consists of the rewrite result on each parent. Running, e.g., --cc on this in --full-diff mode is not very useful: if any commits were skipped, some hunks will disagree with all sides of the merge (with one side, because commits were skipped; with the others, because they didn't have those changes in the first place). This triggers --cc showing these hunks spuriously. Therefore I believe that even for merge commits it is better to show the diffs wrt. the original parents. Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Helped-by: Junio C Hamano <gitster@pobox.com> Helped-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk> Signed-off-by: Thomas Rast <trast@inf.ethz.ch> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-31 20:13:20 +00:00
static inline int want_ancestry(const struct rev_info *revs)
{
return (revs->rewrite_parents || revs->children.name);
}
/*
* Return a timestamp to be used for --since/--until comparisons for this
* commit, based on the revision options.
*/
static timestamp_t comparison_date(const struct rev_info *revs,
struct commit *commit)
{
return revs->reflog_info ?
get_reflog_timestamp(revs->reflog_info) :
commit->date;
}
enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
Enhance --early-output format This makes --early-output a bit more advanced, and actually makes it generate multiple "Final output:" headers as it updates things asynchronously. I realize that the "Final output:" line is now illogical, since it's not really final until it also says "done", but It now _always_ generates a "Final output:" header in front of any commit list, and that output header gives you a *guess* at the maximum number of commits available. However, it should be noted that the guess can be completely off: I do a reasonable job estimating it, but it is not meant to be exact. So what happens is that you may get output like this: - at 0.1 seconds: Final output: 2 incomplete .. 2 commits listed .. - half a second later: Final output: 33 incomplete .. 33 commits listed .. - another half a second after that: Final output: 71 incomplete .. 71 commits listed .. - another half second later: Final output: 136 incomplete .. 100 commits listed: we hit the --early-output limit, and .. will only output 100 commits, and after this you'll not .. see an "incomplete" report any more since you got as much .. early output as you asked for! - .. and then finally: Final output: 73106 done .. all the commits .. The above is a real-life scenario on my current kernel tree after having flushed all the caches. Tested with the experimental gitk patch that Paul sent out, and by looking at the actual log output (and verifying that my commit count guesses actually match real life fairly well). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-04 20:12:05 +00:00
{
if (commit->object.flags & SHOWN)
return commit_ignore;
if (revs->unpacked && has_object_pack(&commit->object.oid))
Enhance --early-output format This makes --early-output a bit more advanced, and actually makes it generate multiple "Final output:" headers as it updates things asynchronously. I realize that the "Final output:" line is now illogical, since it's not really final until it also says "done", but It now _always_ generates a "Final output:" header in front of any commit list, and that output header gives you a *guess* at the maximum number of commits available. However, it should be noted that the guess can be completely off: I do a reasonable job estimating it, but it is not meant to be exact. So what happens is that you may get output like this: - at 0.1 seconds: Final output: 2 incomplete .. 2 commits listed .. - half a second later: Final output: 33 incomplete .. 33 commits listed .. - another half a second after that: Final output: 71 incomplete .. 71 commits listed .. - another half second later: Final output: 136 incomplete .. 100 commits listed: we hit the --early-output limit, and .. will only output 100 commits, and after this you'll not .. see an "incomplete" report any more since you got as much .. early output as you asked for! - .. and then finally: Final output: 73106 done .. all the commits .. The above is a real-life scenario on my current kernel tree after having flushed all the caches. Tested with the experimental gitk patch that Paul sent out, and by looking at the actual log output (and verifying that my commit count guesses actually match real life fairly well). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-04 20:12:05 +00:00
return commit_ignore;
revision: learn '--no-kept-objects' A future caller will want to be able to perform a reachability traversal which terminates when visiting an object found in a kept pack. The closest existing option is '--honor-pack-keep', but this isn't quite what we want. Instead of halting the traversal midway through, a full traversal is always performed, and the results are only trimmed afterwords. Besides needing to introduce a new flag (since culling results post-facto can be different than halting the traversal as it's happening), there is an additional wrinkle handling the distinction in-core and on-disk kept packs. That is: what kinds of kept pack should stop the traversal? Introduce '--no-kept-objects[=<on-disk|in-core>]' to specify which kinds of kept packs, if any, should stop a traversal. This can be useful for callers that want to perform a reachability analysis, but want to leave certain packs alone (for e.g., when doing a geometric repack that has some "large" packs which are kept in-core that it wants to leave alone). Note that this option is not guaranteed to produce exactly the set of objects that aren't in kept packs, since it's possible the traversal order may end up in a situation where a non-kept ancestor was "cut off" by a kept object (at which point we would stop traversing). But, we don't care about absolute correctness here, since this will eventually be used as a purely additive guide in an upcoming new repack mode. Explicitly avoid documenting this new flag, since it is only used internally. In theory we could avoid even adding it rev-list, but being able to spell this option out on the command-line makes some special cases easier to test without promising to keep it behaving consistently forever. Those tricky cases are exercised in t6114. Signed-off-by: Taylor Blau <me@ttaylorr.com> Reviewed-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-23 02:25:07 +00:00
if (revs->no_kept_objects) {
if (has_object_kept_pack(&commit->object.oid,
revs->keep_pack_cache_flags))
return commit_ignore;
}
Enhance --early-output format This makes --early-output a bit more advanced, and actually makes it generate multiple "Final output:" headers as it updates things asynchronously. I realize that the "Final output:" line is now illogical, since it's not really final until it also says "done", but It now _always_ generates a "Final output:" header in front of any commit list, and that output header gives you a *guess* at the maximum number of commits available. However, it should be noted that the guess can be completely off: I do a reasonable job estimating it, but it is not meant to be exact. So what happens is that you may get output like this: - at 0.1 seconds: Final output: 2 incomplete .. 2 commits listed .. - half a second later: Final output: 33 incomplete .. 33 commits listed .. - another half a second after that: Final output: 71 incomplete .. 71 commits listed .. - another half second later: Final output: 136 incomplete .. 100 commits listed: we hit the --early-output limit, and .. will only output 100 commits, and after this you'll not .. see an "incomplete" report any more since you got as much .. early output as you asked for! - .. and then finally: Final output: 73106 done .. all the commits .. The above is a real-life scenario on my current kernel tree after having flushed all the caches. Tested with the experimental gitk patch that Paul sent out, and by looking at the actual log output (and verifying that my commit count guesses actually match real life fairly well). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-04 20:12:05 +00:00
if (commit->object.flags & UNINTERESTING)
return commit_ignore;
line-log: more responsive, incremental 'git log -L' The current line-level log implementation performs a preprocessing step in prepare_revision_walk(), during which the line_log_filter() function filters and rewrites history to keep only commits modifying the given line range. This preprocessing affects both responsiveness and correctness: - Git doesn't produce any output during this preprocessing step. Checking whether a commit modified the given line range is somewhat expensive, so depending on the size of the given revision range this preprocessing can result in a significant delay before the first commit is shown. - Limiting the number of displayed commits (e.g. 'git log -3 -L...') doesn't limit the amount of work during preprocessing, because that limit is applied during history traversal. Alas, by that point this expensive preprocessing step has already churned through the whole revision range to find all commits modifying the revision range, even though only a few of them need to be shown. - It rewrites parents, with no way to turn it off. Without the user explicitly requesting parent rewriting any parent object ID shown should be that of the immediate parent, just like in case of a pathspec-limited history traversal without parent rewriting. However, after that preprocessing step rewrote history, the subsequent "regular" history traversal (i.e. get_revision() in a loop) only sees commits modifying the given line range. Consequently, it can only show the object ID of the last ancestor that modified the given line range (which might happen to be the immediate parent, but many-many times it isn't). This patch addresses both the correctness and, at least for the common case, the responsiveness issues by integrating line-level log filtering into the regular revision walking machinery: - Make process_ranges_arbitrary_commit(), the static function in 'line-log.c' deciding whether a commit modifies the given line range, public by removing the static keyword and adding the 'line_log_' prefix, so it can be called from other parts of the revision walking machinery. - If the user didn't explicitly ask for parent rewriting (which, I believe, is the most common case): - Call this now-public function during regular history traversal, namely from get_commit_action() to ignore any commits not modifying the given line range. Note that while this check is relatively expensive, it must be performed before other, much cheaper conditions, because the tracked line range must be adjusted even when the commit will end up being ignored by other conditions. - Skip the line_log_filter() call, i.e. the expensive preprocessing step, in prepare_revision_walk(), because, thanks to the above points, the revision walking machinery is now able to filter out commits not modifying the given line range while traversing history. This way the regular history traversal sees the unmodified history, and is therefore able to print the object ids of the immediate parents of the listed commits. The eliminated preprocessing step can greatly reduce the delay before the first commit is shown, see the numbers below. - However, if the user did explicitly ask for parent rewriting via '--parents' or a similar option, then stick with the current implementation for now, i.e. perform that expensive filtering and history rewriting in the preprocessing step just like we did before, leaving the initial delay as long as it was. I tried to integrate line-level log filtering with parent rewriting into the regular history traversal, but, unfortunately, several subtleties resisted... :) Maybe someday we'll figure out how to do that, but until then at least the simple and common (i.e. without parent rewriting) 'git log -L:func:file' commands can benefit from the reduced delay. This change makes the failing 'parent oids without parent rewriting' test in 't4211-line-log.sh' succeed. The reduced delay is most noticable when there's a commit modifying the line range near the tip of a large-ish revision range: # no parent rewriting requested, no commit-graph present $ time git --no-pager log -L:read_alternate_refs:sha1-file.c -1 v2.23.0 Before: real 0m9.570s user 0m9.494s sys 0m0.076s After: real 0m0.718s user 0m0.674s sys 0m0.044s A significant part of the remaining delay is spent reading and parsing commit objects in limit_list(). With the help of the commit-graph we can eliminate most of that reading and parsing overhead, so here are the timing results of the same command as above, but this time using the commit-graph: Before: real 0m8.874s user 0m8.816s sys 0m0.057s After: real 0m0.107s user 0m0.091s sys 0m0.013s The next patch will further reduce the remaining delay. To be clear: this patch doesn't actually optimize the line-level log, but merely moves most of the work from the preprocessing step to the history traversal, so the commits modifying the line range can be shown as soon as they are processed, and the traversal can be terminated as soon as the given number of commits are shown. Consequently, listing the full history of a line range, potentially all the way to the root commit, will take the same time as before (but at least the user might start reading the output earlier). Furthermore, if the most recent commit modifying the line range is far away from the starting revision, then that initial delay will still be significant. Additional testing by Derrick Stolee: In the Linux kernel repository, the MAINTAINERS file was changed ~3,500 times across the ~915,000 commits. In addition to that edit frequency, the file itself is quite large (~18,700 lines). This means that a significant portion of the computation is taken up by computing the patch-diff of the file. This patch improves the real time it takes to output the first result quite a bit: Command: git log -L 100,200:MAINTAINERS -n 1 >/dev/null Before: 3.88 s After: 0.71 s If we drop the "-n 1" in the command, then there is no change in end-to-end process time. This is because the command still needs to walk the entire commit history, which negates the point of this patch. This is expected. As a note for future reference, the ~4.3 seconds in the old code spends ~2.6 seconds computing the patch-diffs, and the rest of the time is spent walking commits and computing diffs for which paths changed at each commit. The changed-path Bloom filters could improve the end-to-end computation time (i.e. no "-n 1" in the command). Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-11 11:56:17 +00:00
if (revs->line_level_traverse && !want_ancestry(revs)) {
/*
* In case of line-level log with parent rewriting
* prepare_revision_walk() already took care of all line-level
* log filtering, and there is nothing left to do here.
*
* If parent rewriting was not requested, then this is the
* place to perform the line-level log filtering. Notably,
* this check, though expensive, must come before the other,
* cheaper filtering conditions, because the tracked line
* ranges must be adjusted even when the commit will end up
* being ignored based on other conditions.
*/
if (!line_log_process_ranges_arbitrary_commit(revs, commit))
return commit_ignore;
}
if (revs->min_age != -1 &&
comparison_date(revs, commit) > revs->min_age)
return commit_ignore;
if (revs->min_parents || (revs->max_parents >= 0)) {
int n = commit_list_count(commit->parents);
if ((n < revs->min_parents) ||
((revs->max_parents >= 0) && (n > revs->max_parents)))
return commit_ignore;
}
Enhance --early-output format This makes --early-output a bit more advanced, and actually makes it generate multiple "Final output:" headers as it updates things asynchronously. I realize that the "Final output:" line is now illogical, since it's not really final until it also says "done", but It now _always_ generates a "Final output:" header in front of any commit list, and that output header gives you a *guess* at the maximum number of commits available. However, it should be noted that the guess can be completely off: I do a reasonable job estimating it, but it is not meant to be exact. So what happens is that you may get output like this: - at 0.1 seconds: Final output: 2 incomplete .. 2 commits listed .. - half a second later: Final output: 33 incomplete .. 33 commits listed .. - another half a second after that: Final output: 71 incomplete .. 71 commits listed .. - another half second later: Final output: 136 incomplete .. 100 commits listed: we hit the --early-output limit, and .. will only output 100 commits, and after this you'll not .. see an "incomplete" report any more since you got as much .. early output as you asked for! - .. and then finally: Final output: 73106 done .. all the commits .. The above is a real-life scenario on my current kernel tree after having flushed all the caches. Tested with the experimental gitk patch that Paul sent out, and by looking at the actual log output (and verifying that my commit count guesses actually match real life fairly well). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-04 20:12:05 +00:00
if (!commit_match(commit, revs))
return commit_ignore;
if (revs->prune && revs->dense) {
Enhance --early-output format This makes --early-output a bit more advanced, and actually makes it generate multiple "Final output:" headers as it updates things asynchronously. I realize that the "Final output:" line is now illogical, since it's not really final until it also says "done", but It now _always_ generates a "Final output:" header in front of any commit list, and that output header gives you a *guess* at the maximum number of commits available. However, it should be noted that the guess can be completely off: I do a reasonable job estimating it, but it is not meant to be exact. So what happens is that you may get output like this: - at 0.1 seconds: Final output: 2 incomplete .. 2 commits listed .. - half a second later: Final output: 33 incomplete .. 33 commits listed .. - another half a second after that: Final output: 71 incomplete .. 71 commits listed .. - another half second later: Final output: 136 incomplete .. 100 commits listed: we hit the --early-output limit, and .. will only output 100 commits, and after this you'll not .. see an "incomplete" report any more since you got as much .. early output as you asked for! - .. and then finally: Final output: 73106 done .. all the commits .. The above is a real-life scenario on my current kernel tree after having flushed all the caches. Tested with the experimental gitk patch that Paul sent out, and by looking at the actual log output (and verifying that my commit count guesses actually match real life fairly well). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-04 20:12:05 +00:00
/* Commit without changes? */
if (commit->object.flags & TREESAME) {
int n;
struct commit_list *p;
Enhance --early-output format This makes --early-output a bit more advanced, and actually makes it generate multiple "Final output:" headers as it updates things asynchronously. I realize that the "Final output:" line is now illogical, since it's not really final until it also says "done", but It now _always_ generates a "Final output:" header in front of any commit list, and that output header gives you a *guess* at the maximum number of commits available. However, it should be noted that the guess can be completely off: I do a reasonable job estimating it, but it is not meant to be exact. So what happens is that you may get output like this: - at 0.1 seconds: Final output: 2 incomplete .. 2 commits listed .. - half a second later: Final output: 33 incomplete .. 33 commits listed .. - another half a second after that: Final output: 71 incomplete .. 71 commits listed .. - another half second later: Final output: 136 incomplete .. 100 commits listed: we hit the --early-output limit, and .. will only output 100 commits, and after this you'll not .. see an "incomplete" report any more since you got as much .. early output as you asked for! - .. and then finally: Final output: 73106 done .. all the commits .. The above is a real-life scenario on my current kernel tree after having flushed all the caches. Tested with the experimental gitk patch that Paul sent out, and by looking at the actual log output (and verifying that my commit count guesses actually match real life fairly well). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-04 20:12:05 +00:00
/* drop merges unless we want parenthood */
if (!want_ancestry(revs))
Enhance --early-output format This makes --early-output a bit more advanced, and actually makes it generate multiple "Final output:" headers as it updates things asynchronously. I realize that the "Final output:" line is now illogical, since it's not really final until it also says "done", but It now _always_ generates a "Final output:" header in front of any commit list, and that output header gives you a *guess* at the maximum number of commits available. However, it should be noted that the guess can be completely off: I do a reasonable job estimating it, but it is not meant to be exact. So what happens is that you may get output like this: - at 0.1 seconds: Final output: 2 incomplete .. 2 commits listed .. - half a second later: Final output: 33 incomplete .. 33 commits listed .. - another half a second after that: Final output: 71 incomplete .. 71 commits listed .. - another half second later: Final output: 136 incomplete .. 100 commits listed: we hit the --early-output limit, and .. will only output 100 commits, and after this you'll not .. see an "incomplete" report any more since you got as much .. early output as you asked for! - .. and then finally: Final output: 73106 done .. all the commits .. The above is a real-life scenario on my current kernel tree after having flushed all the caches. Tested with the experimental gitk patch that Paul sent out, and by looking at the actual log output (and verifying that my commit count guesses actually match real life fairly well). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-04 20:12:05 +00:00
return commit_ignore;
revision: --show-pulls adds helpful merges The default file history simplification of "git log -- <path>" or "git rev-list -- <path>" focuses on providing the smallest set of commits that first contributed a change. The revision walk greatly restricts the set of walked commits by visiting only the first TREESAME parent of a merge commit, when one exists. This means that portions of the commit-graph are not walked, which can be a performance benefit, but can also "hide" commits that added changes but were ignored by a merge resolution. The --full-history option modifies this by walking all commits and reporting a merge commit as "interesting" if it has _any_ parent that is not TREESAME. This tends to be an over-representation of important commits, especially in an environment where most merge commits are created by pull request completion. Suppose we have a commit A and we create a commit B on top that changes our file. When we merge the pull request, we create a merge commit M. If no one else changed the file in the first-parent history between M and A, then M will not be TREESAME to its first parent, but will be TREESAME to B. Thus, the simplified history will be "B". However, M will appear in the --full-history mode. However, suppose that a number of topics T1, T2, ..., Tn were created based on commits C1, C2, ..., Cn between A and M as follows: A----C1----C2--- ... ---Cn----M------P1---P2--- ... ---Pn \ \ \ \ / / / / \ \__.. \ \/ ..__T1 / Tn \ \__.. /\ ..__T2 / \_____________________B \____________________/ If the commits T1, T2, ... Tn did not change the file, then all of P1 through Pn will be TREESAME to their first parent, but not TREESAME to their second. This means that all of those merge commits appear in the --full-history view, with edges that immediately collapse into the lower history without introducing interesting single-parent commits. The --simplify-merges option was introduced to remove these extra merge commits. By noticing that the rewritten parents are reachable from their first parents, those edges can be simplified away. Finally, the commits now look like single-parent commits that are TREESAME to their "only" parent. Thus, they are removed and this issue does not cause issues anymore. However, this also ends up removing the commit M from the history view! Even worse, the --simplify-merges option requires walking the entire history before returning a single result. Many Git users are using Git alongside a Git service that provides code storage alongside a code review tool commonly called "Pull Requests" or "Merge Requests" against a target branch. When these requests are accepted and merged, they typically create a merge commit whose first parent is the previous branch tip and the second parent is the tip of the topic branch used for the request. This presents a valuable order to the parents, but also makes that merge commit slightly special. Users may want to see not only which commits changed a file, but which pull requests merged those commits into their branch. In the previous example, this would mean the users want to see the merge commit "M" in addition to the single- parent commit "C". Users are even more likely to want these merge commits when they use pull requests to merge into a feature branch before merging that feature branch into their trunk. In some sense, users are asking for the "first" merge commit to bring in the change to their branch. As long as the parent order is consistent, this can be handled with the following rule: Include a merge commit if it is not TREESAME to its first parent, but is TREESAME to a later parent. These merges look like the merge commits that would result from running "git pull <topic>" on a main branch. Thus, the option to show these commits is called "--show-pulls". This has the added benefit of showing the commits created by closing a pull request or merge request on any of the Git hosting and code review platforms. To test these options, extend the standard test example to include a merge commit that is not TREESAME to its first parent. It is surprising that that option was not already in the example, as it is instructive. In particular, this extension demonstrates a common issue with file history simplification. When a user resolves a merge conflict using "-Xours" or otherwise ignoring one side of the conflict, they create a TREESAME edge that probably should not be TREESAME. This leads users to become frustrated and complain that "my change disappeared!" In my experience, showing them history with --full-history and --simplify-merges quickly reveals the problematic merge. As mentioned, this option is expensive to compute. The --show-pulls option _might_ show the merge commit (usually titled "resolving conflicts") more quickly. Of course, this depends on the user having the correct parent order, which is backwards when using "git pull master" from a topic branch. There are some special considerations when combining the --show-pulls option with --simplify-merges. This requires adding a new PULL_MERGE object flag to store the information from the initial TREESAME comparisons. This helps avoid dropping those commits in later filters. This is covered by a test, including how the parents can be simplified. Since "struct object" has already ruined its 32-bit alignment by using 33 bits across parsed, type, and flags member, let's not make it worse. PULL_MERGE is used in revision.c with the same value (1u<<15) as REACHABLE in commit-graph.c. The REACHABLE flag is only used when writing a commit-graph file, and a revision walk using --show-pulls does not happen in the same process. Care must be taken in the future to ensure this remains the case. Update Documentation/rev-list-options.txt with significant details around this option. This requires updating the example in the History Simplification section to demonstrate some of the problems with TREESAME second parents. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-10 12:19:43 +00:00
if (revs->show_pulls && (commit->object.flags & PULL_MERGE))
return commit_show;
/*
* If we want ancestry, then need to keep any merges
* between relevant commits to tie together topology.
* For consistency with TREESAME and simplification
* use "relevant" here rather than just INTERESTING,
* to treat bottom commit(s) as part of the topology.
*/
for (n = 0, p = commit->parents; p; p = p->next)
if (relevant_commit(p->item))
if (++n >= 2)
return commit_show;
return commit_ignore;
Enhance --early-output format This makes --early-output a bit more advanced, and actually makes it generate multiple "Final output:" headers as it updates things asynchronously. I realize that the "Final output:" line is now illogical, since it's not really final until it also says "done", but It now _always_ generates a "Final output:" header in front of any commit list, and that output header gives you a *guess* at the maximum number of commits available. However, it should be noted that the guess can be completely off: I do a reasonable job estimating it, but it is not meant to be exact. So what happens is that you may get output like this: - at 0.1 seconds: Final output: 2 incomplete .. 2 commits listed .. - half a second later: Final output: 33 incomplete .. 33 commits listed .. - another half a second after that: Final output: 71 incomplete .. 71 commits listed .. - another half second later: Final output: 136 incomplete .. 100 commits listed: we hit the --early-output limit, and .. will only output 100 commits, and after this you'll not .. see an "incomplete" report any more since you got as much .. early output as you asked for! - .. and then finally: Final output: 73106 done .. all the commits .. The above is a real-life scenario on my current kernel tree after having flushed all the caches. Tested with the experimental gitk patch that Paul sent out, and by looking at the actual log output (and verifying that my commit count guesses actually match real life fairly well). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-04 20:12:05 +00:00
}
}
return commit_show;
}
define_commit_slab(saved_parents, struct commit_list *);
#define EMPTY_PARENT_LIST ((struct commit_list *)-1)
/*
* You may only call save_parents() once per commit (this is checked
* for non-root commits).
*/
static void save_parents(struct rev_info *revs, struct commit *commit)
{
struct commit_list **pp;
if (!revs->saved_parents_slab) {
revs->saved_parents_slab = xmalloc(sizeof(struct saved_parents));
init_saved_parents(revs->saved_parents_slab);
}
pp = saved_parents_at(revs->saved_parents_slab, commit);
/*
* When walking with reflogs, we may visit the same commit
* several times: once for each appearance in the reflog.
*
* In this case, save_parents() will be called multiple times.
* We want to keep only the first set of parents. We need to
* store a sentinel value for an empty (i.e., NULL) parent
* list to distinguish it from a not-yet-saved list, however.
*/
if (*pp)
return;
if (commit->parents)
*pp = copy_commit_list(commit->parents);
else
*pp = EMPTY_PARENT_LIST;
}
static void free_saved_parents(struct rev_info *revs)
{
if (revs->saved_parents_slab)
clear_saved_parents(revs->saved_parents_slab);
}
struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit)
{
struct commit_list *parents;
if (!revs->saved_parents_slab)
return commit->parents;
parents = *saved_parents_at(revs->saved_parents_slab, commit);
if (parents == EMPTY_PARENT_LIST)
return NULL;
return parents;
}
enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
{
enum commit_action action = get_commit_action(revs, commit);
if (action == commit_show &&
revs->prune && revs->dense && want_ancestry(revs)) {
log: use true parents for diff even when rewriting When using pathspec filtering in combination with diff-based log output, parent simplification happens before the diff is computed. The diff is therefore against the *simplified* parents. This works okay, arguably by accident, in the normal case: simplification reduces to one parent as long as the commit is TREESAME to it. So the simplified parent of any given commit must have the same tree contents on the filtered paths as its true (unfiltered) parent. However, --full-diff breaks this guarantee, and indeed gives pretty spectacular results when comparing the output of git log --graph --stat ... git log --graph --full-diff --stat ... (--graph internally kicks in parent simplification, much like --parents). To fix it, store a copy of the parent list before simplification (in a slab) whenever --full-diff is in effect. Then use the stored parents instead of the simplified ones in the commit display code paths. The latter do not actually check for --full-diff to avoid duplicated code; they just grab the original parents if save_parents() has not been called for this revision walk. For ordinary commits it should be obvious that this is the right thing to do. Merge commits are a bit subtle. Observe that with default simplification, merge simplification is an all-or-nothing decision: either the merge is TREESAME to one parent and disappears, or it is different from all parents and the parent list remains intact. Redundant parents are not pruned, so the existing code also shows them as a merge. So if we do show a merge commit, the parent list just consists of the rewrite result on each parent. Running, e.g., --cc on this in --full-diff mode is not very useful: if any commits were skipped, some hunks will disagree with all sides of the merge (with one side, because commits were skipped; with the others, because they didn't have those changes in the first place). This triggers --cc showing these hunks spuriously. Therefore I believe that even for merge commits it is better to show the diffs wrt. the original parents. Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Helped-by: Junio C Hamano <gitster@pobox.com> Helped-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk> Signed-off-by: Thomas Rast <trast@inf.ethz.ch> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-31 20:13:20 +00:00
/*
* --full-diff on simplified parents is no good: it
* will show spurious changes from the commits that
* were elided. So we save the parents on the side
* when --full-diff is in effect.
*/
if (revs->full_diff)
save_parents(revs, commit);
if (rewrite_parents(revs, commit, rewrite_one) < 0)
return commit_error;
}
return action;
}
static void track_linear(struct rev_info *revs, struct commit *commit)
{
if (revs->track_first_time) {
revs->linear = 1;
revs->track_first_time = 0;
} else {
struct commit_list *p;
for (p = revs->previous_parents; p; p = p->next)
if (p->item == NULL || /* first commit */
oideq(&p->item->object.oid, &commit->object.oid))
break;
revs->linear = p != NULL;
}
if (revs->reverse) {
if (revs->linear)
commit->object.flags |= TRACK_LINEAR;
}
free_commit_list(revs->previous_parents);
revs->previous_parents = copy_commit_list(commit->parents);
}
static struct commit *get_revision_1(struct rev_info *revs)
{
while (1) {
reflog-walk: stop using fake parents The reflog-walk system works by putting a ref's tip into the pending queue, and then "traversing" the reflog by pretending that the parent of each commit is the previous reflog entry. This causes a number of user-visible oddities, as documented in t1414 (and the commit message which introduced it). We can fix all of them in one go by replacing the fake-reflog system with a much simpler one: just keeping a list of reflogs to show, and walking through them entry by entry. The implementation is fairly straight-forward, but there are a few items to note: 1. We obviously must skip calling add_parents_to_list() when we are traversing reflogs, since we do not want to walk the original parents at all. As a result, we must call try_to_simplify_commit() ourselves. There are other parts of add_parents_to_list() we skip, as well, but none of them should matter for a reflog traversal: - We do not allow UNINTERESTING commits, nor symmetric ranges (and we bail when these are used with "-g"). - Using --source makes no sense, since we aren't traversing. The reflog selector shows the same information with more detail. - Using --first-parent is still sensible, since you may want to see the first-parent diff for each entry. But since we're not traversing, we don't need to cull the parent list here. 2. Since we now just walk the reflog entries themselves, rather than starting with the ref tip, we now look at the "new" field of each entry rather than the "old" (i.e., we are showing entries, not faking parents). This removes all of the tricky logic around skipping past root commits. But note that we have no way to show an entry with the null sha1 in its "new" field (because such a commit obviously does not exist). Normally this would not happen, since we delete reflogs along with refs, but there is one special case. When we rename the currently checked out branch, we write two reflog entries into the HEAD log: one where the commit goes away, and another where it comes back. Prior to this commit, we show both entries with identical reflog messages. After this commit, we show only the "comes back" entry. See the update in t3200 which demonstrates this. Arguably either is fine, as the whole double-entry thing is a bit hacky in the first place. And until a recent fix, we truncated the traversal in such a case anyway, which was _definitely_ wrong. 3. We show individual reflogs in order, but choose which reflog to show at each stage based on which has the most recent timestamp. This interleaves the output from multiple reflogs based on date order, which is probably what you'd want with limiting like "-n 30". Note that the implementation aims for simplicity. It does a linear walk over the reflog queue for each commit it pulls, which may perform badly if you interleave an enormous number of reflogs. That seems like an unlikely use case; if we did want to handle it, we could probably keep a priority queue of reflogs, ordered by the timestamp of their current tip entry. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-07 09:14:07 +00:00
struct commit *commit;
reflog-walk: stop using fake parents The reflog-walk system works by putting a ref's tip into the pending queue, and then "traversing" the reflog by pretending that the parent of each commit is the previous reflog entry. This causes a number of user-visible oddities, as documented in t1414 (and the commit message which introduced it). We can fix all of them in one go by replacing the fake-reflog system with a much simpler one: just keeping a list of reflogs to show, and walking through them entry by entry. The implementation is fairly straight-forward, but there are a few items to note: 1. We obviously must skip calling add_parents_to_list() when we are traversing reflogs, since we do not want to walk the original parents at all. As a result, we must call try_to_simplify_commit() ourselves. There are other parts of add_parents_to_list() we skip, as well, but none of them should matter for a reflog traversal: - We do not allow UNINTERESTING commits, nor symmetric ranges (and we bail when these are used with "-g"). - Using --source makes no sense, since we aren't traversing. The reflog selector shows the same information with more detail. - Using --first-parent is still sensible, since you may want to see the first-parent diff for each entry. But since we're not traversing, we don't need to cull the parent list here. 2. Since we now just walk the reflog entries themselves, rather than starting with the ref tip, we now look at the "new" field of each entry rather than the "old" (i.e., we are showing entries, not faking parents). This removes all of the tricky logic around skipping past root commits. But note that we have no way to show an entry with the null sha1 in its "new" field (because such a commit obviously does not exist). Normally this would not happen, since we delete reflogs along with refs, but there is one special case. When we rename the currently checked out branch, we write two reflog entries into the HEAD log: one where the commit goes away, and another where it comes back. Prior to this commit, we show both entries with identical reflog messages. After this commit, we show only the "comes back" entry. See the update in t3200 which demonstrates this. Arguably either is fine, as the whole double-entry thing is a bit hacky in the first place. And until a recent fix, we truncated the traversal in such a case anyway, which was _definitely_ wrong. 3. We show individual reflogs in order, but choose which reflog to show at each stage based on which has the most recent timestamp. This interleaves the output from multiple reflogs based on date order, which is probably what you'd want with limiting like "-n 30". Note that the implementation aims for simplicity. It does a linear walk over the reflog queue for each commit it pulls, which may perform badly if you interleave an enormous number of reflogs. That seems like an unlikely use case; if we did want to handle it, we could probably keep a priority queue of reflogs, ordered by the timestamp of their current tip entry. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-07 09:14:07 +00:00
if (revs->reflog_info)
commit = next_reflog_entry(revs->reflog_info);
revision.c: begin refactoring --topo-order logic When running 'git rev-list --topo-order' and its kin, the topo_order setting in struct rev_info implies the limited setting. This means that the following things happen during prepare_revision_walk(): * revs->limited implies we run limit_list() to walk the entire reachable set. There are some short-cuts here, such as if we perform a range query like 'git rev-list COMPARE..HEAD' and we can stop limit_list() when all queued commits are uninteresting. * revs->topo_order implies we run sort_in_topological_order(). See the implementation of that method in commit.c. It implies that the full set of commits to order is in the given commit_list. These two methods imply that a 'git rev-list --topo-order HEAD' command must walk the entire reachable set of commits _twice_ before returning a single result. If we have a commit-graph file with generation numbers computed, then there is a better way. This patch introduces some necessary logic redirection when we are in this situation. In v2.18.0, the commit-graph file contains zero-valued bytes in the positions where the generation number is stored in v2.19.0 and later. Thus, we use generation_numbers_enabled() to check if the commit-graph is available and has non-zero generation numbers. When setting revs->limited only because revs->topo_order is true, only do so if generation numbers are not available. There is no reason to use the new logic as it will behave similarly when all generation numbers are INFINITY or ZERO. In prepare_revision_walk(), if we have revs->topo_order but not revs->limited, then we trigger the new logic. It breaks the logic into three pieces, to fit with the existing framework: 1. init_topo_walk() fills a new struct topo_walk_info in the rev_info struct. We use the presence of this struct as a signal to use the new methods during our walk. In this patch, this method simply calls limit_list() and sort_in_topological_order(). In the future, this method will set up a new data structure to perform that logic in-line. 2. next_topo_commit() provides get_revision_1() with the next topo- ordered commit in the list. Currently, this simply pops the commit from revs->commits. 3. expand_topo_walk() provides get_revision_1() with a way to signal walking beyond the latest commit. Currently, this calls add_parents_to_list() exactly like the old logic. While this commit presents method redirection for performing the exact same logic as before, it allows the next commit to focus only on the new logic. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:20 +00:00
else if (revs->topo_walk_info)
commit = next_topo_commit(revs);
reflog-walk: stop using fake parents The reflog-walk system works by putting a ref's tip into the pending queue, and then "traversing" the reflog by pretending that the parent of each commit is the previous reflog entry. This causes a number of user-visible oddities, as documented in t1414 (and the commit message which introduced it). We can fix all of them in one go by replacing the fake-reflog system with a much simpler one: just keeping a list of reflogs to show, and walking through them entry by entry. The implementation is fairly straight-forward, but there are a few items to note: 1. We obviously must skip calling add_parents_to_list() when we are traversing reflogs, since we do not want to walk the original parents at all. As a result, we must call try_to_simplify_commit() ourselves. There are other parts of add_parents_to_list() we skip, as well, but none of them should matter for a reflog traversal: - We do not allow UNINTERESTING commits, nor symmetric ranges (and we bail when these are used with "-g"). - Using --source makes no sense, since we aren't traversing. The reflog selector shows the same information with more detail. - Using --first-parent is still sensible, since you may want to see the first-parent diff for each entry. But since we're not traversing, we don't need to cull the parent list here. 2. Since we now just walk the reflog entries themselves, rather than starting with the ref tip, we now look at the "new" field of each entry rather than the "old" (i.e., we are showing entries, not faking parents). This removes all of the tricky logic around skipping past root commits. But note that we have no way to show an entry with the null sha1 in its "new" field (because such a commit obviously does not exist). Normally this would not happen, since we delete reflogs along with refs, but there is one special case. When we rename the currently checked out branch, we write two reflog entries into the HEAD log: one where the commit goes away, and another where it comes back. Prior to this commit, we show both entries with identical reflog messages. After this commit, we show only the "comes back" entry. See the update in t3200 which demonstrates this. Arguably either is fine, as the whole double-entry thing is a bit hacky in the first place. And until a recent fix, we truncated the traversal in such a case anyway, which was _definitely_ wrong. 3. We show individual reflogs in order, but choose which reflog to show at each stage based on which has the most recent timestamp. This interleaves the output from multiple reflogs based on date order, which is probably what you'd want with limiting like "-n 30". Note that the implementation aims for simplicity. It does a linear walk over the reflog queue for each commit it pulls, which may perform badly if you interleave an enormous number of reflogs. That seems like an unlikely use case; if we did want to handle it, we could probably keep a priority queue of reflogs, ordered by the timestamp of their current tip entry. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-07 09:14:07 +00:00
else
commit = pop_commit(&revs->commits);
Make path-limiting be incremental when possible. This makes git-rev-list able to do path-limiting without having to parse all of history before it starts showing the results. This makes things like "git log -- pathname" much more pleasant to use. This is actually a pretty small patch, and the biggest part of it is purely cleanups (turning the "goto next" statements into "continue"), but it's conceptually a lot bigger than it looks. What it does is that if you do a path-limited revision list, and you do _not_ ask for pseudo-parenthood information, it won't do all the path-limiting up-front, but instead do it incrementally in "get_revision()". This is an absolutely huge deal for anything like "git log -- <pathname>", but also for some things that we don't do yet - like the "find where things changed" logic I've described elsewhere, where we want to find the previous revision that changed a file. The reason I put "RFC" in the subject line is that while I've validated it various ways, like doing git-rev-list HEAD -- drivers/char/ | md5sum before-and-after on the kernel archive, it's "git-rev-list" after all. In other words, it's that really really subtle and complex central piece of software. So while I think this is important and should go in asap, I also think it should get lots of testing and eyeballs looking at the code. Btw, don't even bother testing this with the git archive. git itself is so small that parsing the whole revision history for it takes about a second even with path limiting. The thing that _really_ shows this off is doing git log drivers/ on the kernel archive, or even better, on the _historic_ kernel archive. With this change, the response is instantaneous (although seeking to the end of the result will obviously take as long as it ever did). Before this change, the command would think about the result for tens of seconds - or even minutes, in the case of the bigger old kernel archive - before starting to output the results. NOTE NOTE NOTE! Using path limiting with things like "gitk", which uses the "--parents" flag to actually generate a pseudo-history of the resulting commits won't actually see the improvement in interactivity, since that forces git-rev-list to do the whole-history thing after all. MAYBE we can fix that too at some point, but I won't promise anything. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-03-31 01:05:25 +00:00
if (!commit)
return NULL;
reflog-walk: stop using fake parents The reflog-walk system works by putting a ref's tip into the pending queue, and then "traversing" the reflog by pretending that the parent of each commit is the previous reflog entry. This causes a number of user-visible oddities, as documented in t1414 (and the commit message which introduced it). We can fix all of them in one go by replacing the fake-reflog system with a much simpler one: just keeping a list of reflogs to show, and walking through them entry by entry. The implementation is fairly straight-forward, but there are a few items to note: 1. We obviously must skip calling add_parents_to_list() when we are traversing reflogs, since we do not want to walk the original parents at all. As a result, we must call try_to_simplify_commit() ourselves. There are other parts of add_parents_to_list() we skip, as well, but none of them should matter for a reflog traversal: - We do not allow UNINTERESTING commits, nor symmetric ranges (and we bail when these are used with "-g"). - Using --source makes no sense, since we aren't traversing. The reflog selector shows the same information with more detail. - Using --first-parent is still sensible, since you may want to see the first-parent diff for each entry. But since we're not traversing, we don't need to cull the parent list here. 2. Since we now just walk the reflog entries themselves, rather than starting with the ref tip, we now look at the "new" field of each entry rather than the "old" (i.e., we are showing entries, not faking parents). This removes all of the tricky logic around skipping past root commits. But note that we have no way to show an entry with the null sha1 in its "new" field (because such a commit obviously does not exist). Normally this would not happen, since we delete reflogs along with refs, but there is one special case. When we rename the currently checked out branch, we write two reflog entries into the HEAD log: one where the commit goes away, and another where it comes back. Prior to this commit, we show both entries with identical reflog messages. After this commit, we show only the "comes back" entry. See the update in t3200 which demonstrates this. Arguably either is fine, as the whole double-entry thing is a bit hacky in the first place. And until a recent fix, we truncated the traversal in such a case anyway, which was _definitely_ wrong. 3. We show individual reflogs in order, but choose which reflog to show at each stage based on which has the most recent timestamp. This interleaves the output from multiple reflogs based on date order, which is probably what you'd want with limiting like "-n 30". Note that the implementation aims for simplicity. It does a linear walk over the reflog queue for each commit it pulls, which may perform badly if you interleave an enormous number of reflogs. That seems like an unlikely use case; if we did want to handle it, we could probably keep a priority queue of reflogs, ordered by the timestamp of their current tip entry. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-07 09:14:07 +00:00
if (revs->reflog_info)
reflogs: clear flags properly in corner case The reflog-walking mechanism is based on the regular revision traversal. We just rewrite the parents of each commit in fake_reflog_parent to point to the commit in the next reflog entry instead of the real parents. However, the regular revision traversal tries not to show the same commit twice, and so sets the SHOWN flag on each commit it shows. In a reflog, however, we may want to see the same commit more than once if it appears in the reflog multiple times (which easily happens, for example, if you do a reset to a prior state). The fake_reflog_parent function takes care of this by clearing flags, including SHOWN. Unfortunately, it does so at the very end of the function, and it is possible to return early from the function if there is no fake parent to set up (e.g., because we are at the very first reflog entry on the branch). In such a case the flag is not cleared, and the entry is skipped by the revision traversal machinery as already shown. You can see this by walking the log of a ref which is set to its very first commit more than once (the test below shows such a situation). In this case the reflog walk will fail to show the entry for the initial creation of the ref. We don't want to simply move the flag-clearing to the top of the function; we want to make sure flags set during the fake-parent installation are also cleared. Instead, let's hoist the flag-clearing out of the fake_reflog_parent function entirely. It's not really about fake parents anyway, and the only caller is the get_revision machinery. Reported-by: Martin von Zweigbergk <martin.von.zweigbergk@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Acked-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-11-22 04:42:53 +00:00
commit->object.flags &= ~(ADDED | SEEN | SHOWN);
Make path-limiting be incremental when possible. This makes git-rev-list able to do path-limiting without having to parse all of history before it starts showing the results. This makes things like "git log -- pathname" much more pleasant to use. This is actually a pretty small patch, and the biggest part of it is purely cleanups (turning the "goto next" statements into "continue"), but it's conceptually a lot bigger than it looks. What it does is that if you do a path-limited revision list, and you do _not_ ask for pseudo-parenthood information, it won't do all the path-limiting up-front, but instead do it incrementally in "get_revision()". This is an absolutely huge deal for anything like "git log -- <pathname>", but also for some things that we don't do yet - like the "find where things changed" logic I've described elsewhere, where we want to find the previous revision that changed a file. The reason I put "RFC" in the subject line is that while I've validated it various ways, like doing git-rev-list HEAD -- drivers/char/ | md5sum before-and-after on the kernel archive, it's "git-rev-list" after all. In other words, it's that really really subtle and complex central piece of software. So while I think this is important and should go in asap, I also think it should get lots of testing and eyeballs looking at the code. Btw, don't even bother testing this with the git archive. git itself is so small that parsing the whole revision history for it takes about a second even with path limiting. The thing that _really_ shows this off is doing git log drivers/ on the kernel archive, or even better, on the _historic_ kernel archive. With this change, the response is instantaneous (although seeking to the end of the result will obviously take as long as it ever did). Before this change, the command would think about the result for tens of seconds - or even minutes, in the case of the bigger old kernel archive - before starting to output the results. NOTE NOTE NOTE! Using path limiting with things like "gitk", which uses the "--parents" flag to actually generate a pseudo-history of the resulting commits won't actually see the improvement in interactivity, since that forces git-rev-list to do the whole-history thing after all. MAYBE we can fix that too at some point, but I won't promise anything. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-03-31 01:05:25 +00:00
/*
* If we haven't done the list limiting, we need to look at
* the parents here. We also need to do the date-based limiting
* that we'd otherwise have done in limit_list().
Make path-limiting be incremental when possible. This makes git-rev-list able to do path-limiting without having to parse all of history before it starts showing the results. This makes things like "git log -- pathname" much more pleasant to use. This is actually a pretty small patch, and the biggest part of it is purely cleanups (turning the "goto next" statements into "continue"), but it's conceptually a lot bigger than it looks. What it does is that if you do a path-limited revision list, and you do _not_ ask for pseudo-parenthood information, it won't do all the path-limiting up-front, but instead do it incrementally in "get_revision()". This is an absolutely huge deal for anything like "git log -- <pathname>", but also for some things that we don't do yet - like the "find where things changed" logic I've described elsewhere, where we want to find the previous revision that changed a file. The reason I put "RFC" in the subject line is that while I've validated it various ways, like doing git-rev-list HEAD -- drivers/char/ | md5sum before-and-after on the kernel archive, it's "git-rev-list" after all. In other words, it's that really really subtle and complex central piece of software. So while I think this is important and should go in asap, I also think it should get lots of testing and eyeballs looking at the code. Btw, don't even bother testing this with the git archive. git itself is so small that parsing the whole revision history for it takes about a second even with path limiting. The thing that _really_ shows this off is doing git log drivers/ on the kernel archive, or even better, on the _historic_ kernel archive. With this change, the response is instantaneous (although seeking to the end of the result will obviously take as long as it ever did). Before this change, the command would think about the result for tens of seconds - or even minutes, in the case of the bigger old kernel archive - before starting to output the results. NOTE NOTE NOTE! Using path limiting with things like "gitk", which uses the "--parents" flag to actually generate a pseudo-history of the resulting commits won't actually see the improvement in interactivity, since that forces git-rev-list to do the whole-history thing after all. MAYBE we can fix that too at some point, but I won't promise anything. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-03-31 01:05:25 +00:00
*/
if (!revs->limited) {
if (revs->max_age != -1 &&
comparison_date(revs, commit) < revs->max_age)
revision walker: Fix --boundary when limited This cleans up the boundary processing in the commit walker. It - rips out the boundary logic from the commit walker. Placing "negative" commits in the revs->commits list was Ok if all we cared about "boundary" was the UNINTERESTING limiting case, but conceptually it was wrong. - makes get_revision_1() function to walk the commits and return the results as if there is no funny postprocessing flags such as --reverse, --skip nor --max-count. - makes get_revision() function the postprocessing phase: If reverse is given, wait for get_revision_1() to give everything that it would normally give, and then reverse it before consuming. If skip is given, skip that many before going further. If max is given, stop when we gave out that many. Now that we are about to return one positive commit, mark the parents of that commit to be potential boundaries before returning, iff we are doing the boundary processing. Return the commit. - After get_revision() finishes giving out all the positive commits, if we are doing the boundary processing, we look at the parents that we marked as potential boundaries earlier, see if they are really boundaries, and give them out. It loses more code than it adds, even when the new gc_boundary() function, which is purely for early optimization, is counted. Note that this patch is purely for eyeballing and discussion only. It breaks git-bundle's verify logic because the logic does not use BOUNDARY_SHOW flag for its internal computation anymore. After we correct it not to attempt to affect the boundary processing by setting the BOUNDARY_SHOW flag, we can remove BOUNDARY_SHOW from revision.h and use that bit assignment for the new CHILD_SHOWN flag. Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-05 21:10:06 +00:00
continue;
reflog-walk: stop using fake parents The reflog-walk system works by putting a ref's tip into the pending queue, and then "traversing" the reflog by pretending that the parent of each commit is the previous reflog entry. This causes a number of user-visible oddities, as documented in t1414 (and the commit message which introduced it). We can fix all of them in one go by replacing the fake-reflog system with a much simpler one: just keeping a list of reflogs to show, and walking through them entry by entry. The implementation is fairly straight-forward, but there are a few items to note: 1. We obviously must skip calling add_parents_to_list() when we are traversing reflogs, since we do not want to walk the original parents at all. As a result, we must call try_to_simplify_commit() ourselves. There are other parts of add_parents_to_list() we skip, as well, but none of them should matter for a reflog traversal: - We do not allow UNINTERESTING commits, nor symmetric ranges (and we bail when these are used with "-g"). - Using --source makes no sense, since we aren't traversing. The reflog selector shows the same information with more detail. - Using --first-parent is still sensible, since you may want to see the first-parent diff for each entry. But since we're not traversing, we don't need to cull the parent list here. 2. Since we now just walk the reflog entries themselves, rather than starting with the ref tip, we now look at the "new" field of each entry rather than the "old" (i.e., we are showing entries, not faking parents). This removes all of the tricky logic around skipping past root commits. But note that we have no way to show an entry with the null sha1 in its "new" field (because such a commit obviously does not exist). Normally this would not happen, since we delete reflogs along with refs, but there is one special case. When we rename the currently checked out branch, we write two reflog entries into the HEAD log: one where the commit goes away, and another where it comes back. Prior to this commit, we show both entries with identical reflog messages. After this commit, we show only the "comes back" entry. See the update in t3200 which demonstrates this. Arguably either is fine, as the whole double-entry thing is a bit hacky in the first place. And until a recent fix, we truncated the traversal in such a case anyway, which was _definitely_ wrong. 3. We show individual reflogs in order, but choose which reflog to show at each stage based on which has the most recent timestamp. This interleaves the output from multiple reflogs based on date order, which is probably what you'd want with limiting like "-n 30". Note that the implementation aims for simplicity. It does a linear walk over the reflog queue for each commit it pulls, which may perform badly if you interleave an enormous number of reflogs. That seems like an unlikely use case; if we did want to handle it, we could probably keep a priority queue of reflogs, ordered by the timestamp of their current tip entry. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-07 09:14:07 +00:00
if (revs->reflog_info)
try_to_simplify_commit(revs, commit);
revision.c: begin refactoring --topo-order logic When running 'git rev-list --topo-order' and its kin, the topo_order setting in struct rev_info implies the limited setting. This means that the following things happen during prepare_revision_walk(): * revs->limited implies we run limit_list() to walk the entire reachable set. There are some short-cuts here, such as if we perform a range query like 'git rev-list COMPARE..HEAD' and we can stop limit_list() when all queued commits are uninteresting. * revs->topo_order implies we run sort_in_topological_order(). See the implementation of that method in commit.c. It implies that the full set of commits to order is in the given commit_list. These two methods imply that a 'git rev-list --topo-order HEAD' command must walk the entire reachable set of commits _twice_ before returning a single result. If we have a commit-graph file with generation numbers computed, then there is a better way. This patch introduces some necessary logic redirection when we are in this situation. In v2.18.0, the commit-graph file contains zero-valued bytes in the positions where the generation number is stored in v2.19.0 and later. Thus, we use generation_numbers_enabled() to check if the commit-graph is available and has non-zero generation numbers. When setting revs->limited only because revs->topo_order is true, only do so if generation numbers are not available. There is no reason to use the new logic as it will behave similarly when all generation numbers are INFINITY or ZERO. In prepare_revision_walk(), if we have revs->topo_order but not revs->limited, then we trigger the new logic. It breaks the logic into three pieces, to fit with the existing framework: 1. init_topo_walk() fills a new struct topo_walk_info in the rev_info struct. We use the presence of this struct as a signal to use the new methods during our walk. In this patch, this method simply calls limit_list() and sort_in_topological_order(). In the future, this method will set up a new data structure to perform that logic in-line. 2. next_topo_commit() provides get_revision_1() with the next topo- ordered commit in the list. Currently, this simply pops the commit from revs->commits. 3. expand_topo_walk() provides get_revision_1() with a way to signal walking beyond the latest commit. Currently, this calls add_parents_to_list() exactly like the old logic. While this commit presents method redirection for performing the exact same logic as before, it allows the next commit to focus only on the new logic. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-01 13:46:20 +00:00
else if (revs->topo_walk_info)
expand_topo_walk(revs, commit);
else if (process_parents(revs, commit, &revs->commits, NULL) < 0) {
add `ignore_missing_links` mode to revwalk When pack-objects is computing the reachability bitmap to serve a fetch request, it can erroneously die() if some of the UNINTERESTING objects are not present. Upload-pack throws away HAVE lines from the client for objects we do not have, but we may have a tip object without all of its ancestors (e.g., if the tip is no longer reachable and was new enough to survive a `git prune`, but some of its reachable objects did get pruned). In the non-bitmap case, we do a revision walk with the HAVE objects marked as UNINTERESTING. The revision walker explicitly ignores errors in accessing UNINTERESTING commits to handle this case (and we do not bother looking at UNINTERESTING trees or blobs at all). When we have bitmaps, however, the process is quite different. The bitmap index for a pack-objects run is calculated in two separate steps: First, we perform an extensive walk from all the HAVEs to find the full set of objects reachable from them. This walk is usually optimized away because we are expected to hit an object with a bitmap during the traversal, which allows us to terminate early. Secondly, we perform an extensive walk from all the WANTs, which usually also terminates early because we hit a commit with an existing bitmap. Once we have the resulting bitmaps from the two walks, we AND-NOT them together to obtain the resulting set of objects we need to pack. When we are walking the HAVE objects, the revision walker does not know that we are walking it only to mark the results as uninteresting. We strip out the UNINTERESTING flag, because those objects _are_ interesting to us during the first walk. We want to keep going to get a complete set of reachable objects if we can. We need some way to tell the revision walker that it's OK to silently truncate the HAVE walk, just like it does for the UNINTERESTING case. This patch introduces a new `ignore_missing_links` flag to the `rev_info` struct, which we set only for the HAVE walk. It also adds tests to cover UNINTERESTING objects missing from several positions: a missing blob, a missing tree, and a missing parent commit. The missing blob already worked (as we do not care about its contents at all), but the other two cases caused us to die(). Note that there are a few cases we do not need to test: 1. We do not need to test a missing tree, with the blob still present. Without the tree that refers to it, we would not know that the blob is relevant to our walk. 2. We do not need to test a tip commit that is missing. Upload-pack omits these for us (and in fact, we complain even in the non-bitmap case if it fails to do so). Reported-by: Siddharth Agarwal <sid0@fb.com> Signed-off-by: Vicent Marti <tanoku@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-03-28 10:00:43 +00:00
if (!revs->ignore_missing_links)
die("Failed to traverse parents of commit %s",
oid_to_hex(&commit->object.oid));
add `ignore_missing_links` mode to revwalk When pack-objects is computing the reachability bitmap to serve a fetch request, it can erroneously die() if some of the UNINTERESTING objects are not present. Upload-pack throws away HAVE lines from the client for objects we do not have, but we may have a tip object without all of its ancestors (e.g., if the tip is no longer reachable and was new enough to survive a `git prune`, but some of its reachable objects did get pruned). In the non-bitmap case, we do a revision walk with the HAVE objects marked as UNINTERESTING. The revision walker explicitly ignores errors in accessing UNINTERESTING commits to handle this case (and we do not bother looking at UNINTERESTING trees or blobs at all). When we have bitmaps, however, the process is quite different. The bitmap index for a pack-objects run is calculated in two separate steps: First, we perform an extensive walk from all the HAVEs to find the full set of objects reachable from them. This walk is usually optimized away because we are expected to hit an object with a bitmap during the traversal, which allows us to terminate early. Secondly, we perform an extensive walk from all the WANTs, which usually also terminates early because we hit a commit with an existing bitmap. Once we have the resulting bitmaps from the two walks, we AND-NOT them together to obtain the resulting set of objects we need to pack. When we are walking the HAVE objects, the revision walker does not know that we are walking it only to mark the results as uninteresting. We strip out the UNINTERESTING flag, because those objects _are_ interesting to us during the first walk. We want to keep going to get a complete set of reachable objects if we can. We need some way to tell the revision walker that it's OK to silently truncate the HAVE walk, just like it does for the UNINTERESTING case. This patch introduces a new `ignore_missing_links` flag to the `rev_info` struct, which we set only for the HAVE walk. It also adds tests to cover UNINTERESTING objects missing from several positions: a missing blob, a missing tree, and a missing parent commit. The missing blob already worked (as we do not care about its contents at all), but the other two cases caused us to die(). Note that there are a few cases we do not need to test: 1. We do not need to test a missing tree, with the blob still present. Without the tree that refers to it, we would not know that the blob is relevant to our walk. 2. We do not need to test a tip commit that is missing. Upload-pack omits these for us (and in fact, we complain even in the non-bitmap case if it fails to do so). Reported-by: Siddharth Agarwal <sid0@fb.com> Signed-off-by: Vicent Marti <tanoku@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-03-28 10:00:43 +00:00
}
}
Enhance --early-output format This makes --early-output a bit more advanced, and actually makes it generate multiple "Final output:" headers as it updates things asynchronously. I realize that the "Final output:" line is now illogical, since it's not really final until it also says "done", but It now _always_ generates a "Final output:" header in front of any commit list, and that output header gives you a *guess* at the maximum number of commits available. However, it should be noted that the guess can be completely off: I do a reasonable job estimating it, but it is not meant to be exact. So what happens is that you may get output like this: - at 0.1 seconds: Final output: 2 incomplete .. 2 commits listed .. - half a second later: Final output: 33 incomplete .. 33 commits listed .. - another half a second after that: Final output: 71 incomplete .. 71 commits listed .. - another half second later: Final output: 136 incomplete .. 100 commits listed: we hit the --early-output limit, and .. will only output 100 commits, and after this you'll not .. see an "incomplete" report any more since you got as much .. early output as you asked for! - .. and then finally: Final output: 73106 done .. all the commits .. The above is a real-life scenario on my current kernel tree after having flushed all the caches. Tested with the experimental gitk patch that Paul sent out, and by looking at the actual log output (and verifying that my commit count guesses actually match real life fairly well). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-04 20:12:05 +00:00
switch (simplify_commit(revs, commit)) {
case commit_ignore:
continue;
Enhance --early-output format This makes --early-output a bit more advanced, and actually makes it generate multiple "Final output:" headers as it updates things asynchronously. I realize that the "Final output:" line is now illogical, since it's not really final until it also says "done", but It now _always_ generates a "Final output:" header in front of any commit list, and that output header gives you a *guess* at the maximum number of commits available. However, it should be noted that the guess can be completely off: I do a reasonable job estimating it, but it is not meant to be exact. So what happens is that you may get output like this: - at 0.1 seconds: Final output: 2 incomplete .. 2 commits listed .. - half a second later: Final output: 33 incomplete .. 33 commits listed .. - another half a second after that: Final output: 71 incomplete .. 71 commits listed .. - another half second later: Final output: 136 incomplete .. 100 commits listed: we hit the --early-output limit, and .. will only output 100 commits, and after this you'll not .. see an "incomplete" report any more since you got as much .. early output as you asked for! - .. and then finally: Final output: 73106 done .. all the commits .. The above is a real-life scenario on my current kernel tree after having flushed all the caches. Tested with the experimental gitk patch that Paul sent out, and by looking at the actual log output (and verifying that my commit count guesses actually match real life fairly well). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-04 20:12:05 +00:00
case commit_error:
die("Failed to simplify parents of commit %s",
oid_to_hex(&commit->object.oid));
Enhance --early-output format This makes --early-output a bit more advanced, and actually makes it generate multiple "Final output:" headers as it updates things asynchronously. I realize that the "Final output:" line is now illogical, since it's not really final until it also says "done", but It now _always_ generates a "Final output:" header in front of any commit list, and that output header gives you a *guess* at the maximum number of commits available. However, it should be noted that the guess can be completely off: I do a reasonable job estimating it, but it is not meant to be exact. So what happens is that you may get output like this: - at 0.1 seconds: Final output: 2 incomplete .. 2 commits listed .. - half a second later: Final output: 33 incomplete .. 33 commits listed .. - another half a second after that: Final output: 71 incomplete .. 71 commits listed .. - another half second later: Final output: 136 incomplete .. 100 commits listed: we hit the --early-output limit, and .. will only output 100 commits, and after this you'll not .. see an "incomplete" report any more since you got as much .. early output as you asked for! - .. and then finally: Final output: 73106 done .. all the commits .. The above is a real-life scenario on my current kernel tree after having flushed all the caches. Tested with the experimental gitk patch that Paul sent out, and by looking at the actual log output (and verifying that my commit count guesses actually match real life fairly well). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-04 20:12:05 +00:00
default:
if (revs->track_linear)
track_linear(revs, commit);
Enhance --early-output format This makes --early-output a bit more advanced, and actually makes it generate multiple "Final output:" headers as it updates things asynchronously. I realize that the "Final output:" line is now illogical, since it's not really final until it also says "done", but It now _always_ generates a "Final output:" header in front of any commit list, and that output header gives you a *guess* at the maximum number of commits available. However, it should be noted that the guess can be completely off: I do a reasonable job estimating it, but it is not meant to be exact. So what happens is that you may get output like this: - at 0.1 seconds: Final output: 2 incomplete .. 2 commits listed .. - half a second later: Final output: 33 incomplete .. 33 commits listed .. - another half a second after that: Final output: 71 incomplete .. 71 commits listed .. - another half second later: Final output: 136 incomplete .. 100 commits listed: we hit the --early-output limit, and .. will only output 100 commits, and after this you'll not .. see an "incomplete" report any more since you got as much .. early output as you asked for! - .. and then finally: Final output: 73106 done .. all the commits .. The above is a real-life scenario on my current kernel tree after having flushed all the caches. Tested with the experimental gitk patch that Paul sent out, and by looking at the actual log output (and verifying that my commit count guesses actually match real life fairly well). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-04 20:12:05 +00:00
return commit;
}
}
}
/*
* Return true for entries that have not yet been shown. (This is an
* object_array_each_func_t.)
*/
static int entry_unshown(struct object_array_entry *entry, void *cb_data_unused)
revision walker: Fix --boundary when limited This cleans up the boundary processing in the commit walker. It - rips out the boundary logic from the commit walker. Placing "negative" commits in the revs->commits list was Ok if all we cared about "boundary" was the UNINTERESTING limiting case, but conceptually it was wrong. - makes get_revision_1() function to walk the commits and return the results as if there is no funny postprocessing flags such as --reverse, --skip nor --max-count. - makes get_revision() function the postprocessing phase: If reverse is given, wait for get_revision_1() to give everything that it would normally give, and then reverse it before consuming. If skip is given, skip that many before going further. If max is given, stop when we gave out that many. Now that we are about to return one positive commit, mark the parents of that commit to be potential boundaries before returning, iff we are doing the boundary processing. Return the commit. - After get_revision() finishes giving out all the positive commits, if we are doing the boundary processing, we look at the parents that we marked as potential boundaries earlier, see if they are really boundaries, and give them out. It loses more code than it adds, even when the new gc_boundary() function, which is purely for early optimization, is counted. Note that this patch is purely for eyeballing and discussion only. It breaks git-bundle's verify logic because the logic does not use BOUNDARY_SHOW flag for its internal computation anymore. After we correct it not to attempt to affect the boundary processing by setting the BOUNDARY_SHOW flag, we can remove BOUNDARY_SHOW from revision.h and use that bit assignment for the new CHILD_SHOWN flag. Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-05 21:10:06 +00:00
{
return !(entry->item->flags & SHOWN);
}
revision walker: Fix --boundary when limited This cleans up the boundary processing in the commit walker. It - rips out the boundary logic from the commit walker. Placing "negative" commits in the revs->commits list was Ok if all we cared about "boundary" was the UNINTERESTING limiting case, but conceptually it was wrong. - makes get_revision_1() function to walk the commits and return the results as if there is no funny postprocessing flags such as --reverse, --skip nor --max-count. - makes get_revision() function the postprocessing phase: If reverse is given, wait for get_revision_1() to give everything that it would normally give, and then reverse it before consuming. If skip is given, skip that many before going further. If max is given, stop when we gave out that many. Now that we are about to return one positive commit, mark the parents of that commit to be potential boundaries before returning, iff we are doing the boundary processing. Return the commit. - After get_revision() finishes giving out all the positive commits, if we are doing the boundary processing, we look at the parents that we marked as potential boundaries earlier, see if they are really boundaries, and give them out. It loses more code than it adds, even when the new gc_boundary() function, which is purely for early optimization, is counted. Note that this patch is purely for eyeballing and discussion only. It breaks git-bundle's verify logic because the logic does not use BOUNDARY_SHOW flag for its internal computation anymore. After we correct it not to attempt to affect the boundary processing by setting the BOUNDARY_SHOW flag, we can remove BOUNDARY_SHOW from revision.h and use that bit assignment for the new CHILD_SHOWN flag. Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-05 21:10:06 +00:00
/*
* If array is on the verge of a realloc, garbage-collect any entries
* that have already been shown to try to free up some space.
*/
static void gc_boundary(struct object_array *array)
{
if (array->nr == array->alloc)
object_array_filter(array, entry_unshown, NULL);
revision walker: Fix --boundary when limited This cleans up the boundary processing in the commit walker. It - rips out the boundary logic from the commit walker. Placing "negative" commits in the revs->commits list was Ok if all we cared about "boundary" was the UNINTERESTING limiting case, but conceptually it was wrong. - makes get_revision_1() function to walk the commits and return the results as if there is no funny postprocessing flags such as --reverse, --skip nor --max-count. - makes get_revision() function the postprocessing phase: If reverse is given, wait for get_revision_1() to give everything that it would normally give, and then reverse it before consuming. If skip is given, skip that many before going further. If max is given, stop when we gave out that many. Now that we are about to return one positive commit, mark the parents of that commit to be potential boundaries before returning, iff we are doing the boundary processing. Return the commit. - After get_revision() finishes giving out all the positive commits, if we are doing the boundary processing, we look at the parents that we marked as potential boundaries earlier, see if they are really boundaries, and give them out. It loses more code than it adds, even when the new gc_boundary() function, which is purely for early optimization, is counted. Note that this patch is purely for eyeballing and discussion only. It breaks git-bundle's verify logic because the logic does not use BOUNDARY_SHOW flag for its internal computation anymore. After we correct it not to attempt to affect the boundary processing by setting the BOUNDARY_SHOW flag, we can remove BOUNDARY_SHOW from revision.h and use that bit assignment for the new CHILD_SHOWN flag. Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-05 21:10:06 +00:00
}
static void create_boundary_commit_list(struct rev_info *revs)
{
unsigned i;
struct commit *c;
struct object_array *array = &revs->boundary_commits;
struct object_array_entry *objects = array->objects;
/*
* If revs->commits is non-NULL at this point, an error occurred in
* get_revision_1(). Ignore the error and continue printing the
* boundary commits anyway. (This is what the code has always
* done.)
*/
if (revs->commits) {
free_commit_list(revs->commits);
revs->commits = NULL;
}
/*
* Put all of the actual boundary commits from revs->boundary_commits
* into revs->commits
*/
for (i = 0; i < array->nr; i++) {
c = (struct commit *)(objects[i].item);
if (!c)
continue;
if (!(c->object.flags & CHILD_SHOWN))
continue;
if (c->object.flags & (SHOWN | BOUNDARY))
continue;
c->object.flags |= BOUNDARY;
commit_list_insert(c, &revs->commits);
}
/*
* If revs->topo_order is set, sort the boundary commits
* in topological order
*/
toposort: rename "lifo" field The primary invariant of sort_in_topological_order() is that a parent commit is not emitted until all children of it are. When traversing a forked history like this with "git log C E": A----B----C \ D----E we ensure that A is emitted after all of B, C, D, and E are done, B has to wait until C is done, and D has to wait until E is done. In some applications, however, we would further want to control how these child commits B, C, D and E on two parallel ancestry chains are shown. Most of the time, we would want to see C and B emitted together, and then E and D, and finally A (i.e. the --topo-order output). The "lifo" parameter of the sort_in_topological_order() function is used to control this behaviour. We start the traversal by knowing two commits, C and E. While keeping in mind that we also need to inspect E later, we pick C first to inspect, and we notice and record that B needs to be inspected. By structuring the "work to be done" set as a LIFO stack, we ensure that B is inspected next, before other in-flight commits we had known that we will need to inspect, e.g. E. When showing in --date-order, we would want to see commits ordered by timestamps, i.e. show C, E, B and D in this order before showing A, possibly mixing commits from two parallel histories together. When "lifo" parameter is set to false, the function keeps the "work to be done" set sorted in the date order to realize this semantics. After inspecting C, we add B to the "work to be done" set, but the next commit we inspect from the set is E which is newer than B. The name "lifo", however, is too strongly tied to the way how the function implements its behaviour, and does not describe what the behaviour _means_. Replace this field with an enum rev_sort_order, with two possible values: REV_SORT_IN_GRAPH_ORDER and REV_SORT_BY_COMMIT_DATE, and update the existing code. The mechanical replacement rule is: "lifo == 0" is equivalent to "sort_order == REV_SORT_BY_COMMIT_DATE" "lifo == 1" is equivalent to "sort_order == REV_SORT_IN_GRAPH_ORDER" Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-06-06 23:07:14 +00:00
sort_in_topological_order(&revs->commits, revs->sort_order);
}
static struct commit *get_revision_internal(struct rev_info *revs)
{
struct commit *c = NULL;
revision walker: Fix --boundary when limited This cleans up the boundary processing in the commit walker. It - rips out the boundary logic from the commit walker. Placing "negative" commits in the revs->commits list was Ok if all we cared about "boundary" was the UNINTERESTING limiting case, but conceptually it was wrong. - makes get_revision_1() function to walk the commits and return the results as if there is no funny postprocessing flags such as --reverse, --skip nor --max-count. - makes get_revision() function the postprocessing phase: If reverse is given, wait for get_revision_1() to give everything that it would normally give, and then reverse it before consuming. If skip is given, skip that many before going further. If max is given, stop when we gave out that many. Now that we are about to return one positive commit, mark the parents of that commit to be potential boundaries before returning, iff we are doing the boundary processing. Return the commit. - After get_revision() finishes giving out all the positive commits, if we are doing the boundary processing, we look at the parents that we marked as potential boundaries earlier, see if they are really boundaries, and give them out. It loses more code than it adds, even when the new gc_boundary() function, which is purely for early optimization, is counted. Note that this patch is purely for eyeballing and discussion only. It breaks git-bundle's verify logic because the logic does not use BOUNDARY_SHOW flag for its internal computation anymore. After we correct it not to attempt to affect the boundary processing by setting the BOUNDARY_SHOW flag, we can remove BOUNDARY_SHOW from revision.h and use that bit assignment for the new CHILD_SHOWN flag. Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-05 21:10:06 +00:00
struct commit_list *l;
if (revs->boundary == 2) {
/*
* All of the normal commits have already been returned,
* and we are now returning boundary commits.
* create_boundary_commit_list() has populated
* revs->commits with the remaining commits to return.
*/
c = pop_commit(&revs->commits);
if (c)
c->object.flags |= SHOWN;
return c;
}
revision walker: Fix --boundary when limited This cleans up the boundary processing in the commit walker. It - rips out the boundary logic from the commit walker. Placing "negative" commits in the revs->commits list was Ok if all we cared about "boundary" was the UNINTERESTING limiting case, but conceptually it was wrong. - makes get_revision_1() function to walk the commits and return the results as if there is no funny postprocessing flags such as --reverse, --skip nor --max-count. - makes get_revision() function the postprocessing phase: If reverse is given, wait for get_revision_1() to give everything that it would normally give, and then reverse it before consuming. If skip is given, skip that many before going further. If max is given, stop when we gave out that many. Now that we are about to return one positive commit, mark the parents of that commit to be potential boundaries before returning, iff we are doing the boundary processing. Return the commit. - After get_revision() finishes giving out all the positive commits, if we are doing the boundary processing, we look at the parents that we marked as potential boundaries earlier, see if they are really boundaries, and give them out. It loses more code than it adds, even when the new gc_boundary() function, which is purely for early optimization, is counted. Note that this patch is purely for eyeballing and discussion only. It breaks git-bundle's verify logic because the logic does not use BOUNDARY_SHOW flag for its internal computation anymore. After we correct it not to attempt to affect the boundary processing by setting the BOUNDARY_SHOW flag, we can remove BOUNDARY_SHOW from revision.h and use that bit assignment for the new CHILD_SHOWN flag. Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-05 21:10:06 +00:00
/*
revision: avoid work after --max-count is reached During a revision traversal in which --max-count has been specified, we decrement a counter for each revision returned by get_revision. When it hits 0, we typically return NULL (the exception being if we still have boundary commits to show). However, before we check the counter, we call get_revision_1 to get the next commit. This might involve looking at a large number of commits if we have restricted the traversal (e.g., we might traverse until we find the next commit whose diff actually matches a pathspec). There's no need to make this get_revision_1 call when our counter runs out. If we are not in --boundary mode, we will just throw away the result and immediately return NULL. If we are in --boundary mode, then we will still throw away the result, and then start showing the boundary commits. However, as git_revision_1 does not impact the boundary list, it should not have an impact. In most cases, avoiding this work will not be especially noticeable. However, in some cases, it can make a big difference: [before] $ time git rev-list -1 origin Documentation/RelNotes/1.7.11.2.txt 8d141a1d562abb31f27f599dbf6e10a6c06ed73e real 0m0.301s user 0m0.280s sys 0m0.016s [after] $ time git rev-list -1 origin Documentation/RelNotes/1.7.11.2.txt 8d141a1d562abb31f27f599dbf6e10a6c06ed73e real 0m0.010s user 0m0.008s sys 0m0.000s Note that the output is produced almost instantaneously in the first case, and then git uselessly spends a long time looking for the next commit to touch that file (but there isn't one, and we traverse all the way down to the roots). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-07-13 07:50:23 +00:00
* If our max_count counter has reached zero, then we are done. We
* don't simply return NULL because we still might need to show
* boundary commits. But we want to avoid calling get_revision_1, which
* might do a considerable amount of work finding the next commit only
* for us to throw it away.
*
* If it is non-zero, then either we don't have a max_count at all
* (-1), or it is still counting, in which case we decrement.
revision walker: Fix --boundary when limited This cleans up the boundary processing in the commit walker. It - rips out the boundary logic from the commit walker. Placing "negative" commits in the revs->commits list was Ok if all we cared about "boundary" was the UNINTERESTING limiting case, but conceptually it was wrong. - makes get_revision_1() function to walk the commits and return the results as if there is no funny postprocessing flags such as --reverse, --skip nor --max-count. - makes get_revision() function the postprocessing phase: If reverse is given, wait for get_revision_1() to give everything that it would normally give, and then reverse it before consuming. If skip is given, skip that many before going further. If max is given, stop when we gave out that many. Now that we are about to return one positive commit, mark the parents of that commit to be potential boundaries before returning, iff we are doing the boundary processing. Return the commit. - After get_revision() finishes giving out all the positive commits, if we are doing the boundary processing, we look at the parents that we marked as potential boundaries earlier, see if they are really boundaries, and give them out. It loses more code than it adds, even when the new gc_boundary() function, which is purely for early optimization, is counted. Note that this patch is purely for eyeballing and discussion only. It breaks git-bundle's verify logic because the logic does not use BOUNDARY_SHOW flag for its internal computation anymore. After we correct it not to attempt to affect the boundary processing by setting the BOUNDARY_SHOW flag, we can remove BOUNDARY_SHOW from revision.h and use that bit assignment for the new CHILD_SHOWN flag. Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-05 21:10:06 +00:00
*/
revision: avoid work after --max-count is reached During a revision traversal in which --max-count has been specified, we decrement a counter for each revision returned by get_revision. When it hits 0, we typically return NULL (the exception being if we still have boundary commits to show). However, before we check the counter, we call get_revision_1 to get the next commit. This might involve looking at a large number of commits if we have restricted the traversal (e.g., we might traverse until we find the next commit whose diff actually matches a pathspec). There's no need to make this get_revision_1 call when our counter runs out. If we are not in --boundary mode, we will just throw away the result and immediately return NULL. If we are in --boundary mode, then we will still throw away the result, and then start showing the boundary commits. However, as git_revision_1 does not impact the boundary list, it should not have an impact. In most cases, avoiding this work will not be especially noticeable. However, in some cases, it can make a big difference: [before] $ time git rev-list -1 origin Documentation/RelNotes/1.7.11.2.txt 8d141a1d562abb31f27f599dbf6e10a6c06ed73e real 0m0.301s user 0m0.280s sys 0m0.016s [after] $ time git rev-list -1 origin Documentation/RelNotes/1.7.11.2.txt 8d141a1d562abb31f27f599dbf6e10a6c06ed73e real 0m0.010s user 0m0.008s sys 0m0.000s Note that the output is produced almost instantaneously in the first case, and then git uselessly spends a long time looking for the next commit to touch that file (but there isn't one, and we traverse all the way down to the roots). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-07-13 07:50:23 +00:00
if (revs->max_count) {
c = get_revision_1(revs);
if (c) {
while (revs->skip_count > 0) {
revision: avoid work after --max-count is reached During a revision traversal in which --max-count has been specified, we decrement a counter for each revision returned by get_revision. When it hits 0, we typically return NULL (the exception being if we still have boundary commits to show). However, before we check the counter, we call get_revision_1 to get the next commit. This might involve looking at a large number of commits if we have restricted the traversal (e.g., we might traverse until we find the next commit whose diff actually matches a pathspec). There's no need to make this get_revision_1 call when our counter runs out. If we are not in --boundary mode, we will just throw away the result and immediately return NULL. If we are in --boundary mode, then we will still throw away the result, and then start showing the boundary commits. However, as git_revision_1 does not impact the boundary list, it should not have an impact. In most cases, avoiding this work will not be especially noticeable. However, in some cases, it can make a big difference: [before] $ time git rev-list -1 origin Documentation/RelNotes/1.7.11.2.txt 8d141a1d562abb31f27f599dbf6e10a6c06ed73e real 0m0.301s user 0m0.280s sys 0m0.016s [after] $ time git rev-list -1 origin Documentation/RelNotes/1.7.11.2.txt 8d141a1d562abb31f27f599dbf6e10a6c06ed73e real 0m0.010s user 0m0.008s sys 0m0.000s Note that the output is produced almost instantaneously in the first case, and then git uselessly spends a long time looking for the next commit to touch that file (but there isn't one, and we traverse all the way down to the roots). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-07-13 07:50:23 +00:00
revs->skip_count--;
c = get_revision_1(revs);
if (!c)
break;
}
}
revision walker: Fix --boundary when limited This cleans up the boundary processing in the commit walker. It - rips out the boundary logic from the commit walker. Placing "negative" commits in the revs->commits list was Ok if all we cared about "boundary" was the UNINTERESTING limiting case, but conceptually it was wrong. - makes get_revision_1() function to walk the commits and return the results as if there is no funny postprocessing flags such as --reverse, --skip nor --max-count. - makes get_revision() function the postprocessing phase: If reverse is given, wait for get_revision_1() to give everything that it would normally give, and then reverse it before consuming. If skip is given, skip that many before going further. If max is given, stop when we gave out that many. Now that we are about to return one positive commit, mark the parents of that commit to be potential boundaries before returning, iff we are doing the boundary processing. Return the commit. - After get_revision() finishes giving out all the positive commits, if we are doing the boundary processing, we look at the parents that we marked as potential boundaries earlier, see if they are really boundaries, and give them out. It loses more code than it adds, even when the new gc_boundary() function, which is purely for early optimization, is counted. Note that this patch is purely for eyeballing and discussion only. It breaks git-bundle's verify logic because the logic does not use BOUNDARY_SHOW flag for its internal computation anymore. After we correct it not to attempt to affect the boundary processing by setting the BOUNDARY_SHOW flag, we can remove BOUNDARY_SHOW from revision.h and use that bit assignment for the new CHILD_SHOWN flag. Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-05 21:10:06 +00:00
revision: avoid work after --max-count is reached During a revision traversal in which --max-count has been specified, we decrement a counter for each revision returned by get_revision. When it hits 0, we typically return NULL (the exception being if we still have boundary commits to show). However, before we check the counter, we call get_revision_1 to get the next commit. This might involve looking at a large number of commits if we have restricted the traversal (e.g., we might traverse until we find the next commit whose diff actually matches a pathspec). There's no need to make this get_revision_1 call when our counter runs out. If we are not in --boundary mode, we will just throw away the result and immediately return NULL. If we are in --boundary mode, then we will still throw away the result, and then start showing the boundary commits. However, as git_revision_1 does not impact the boundary list, it should not have an impact. In most cases, avoiding this work will not be especially noticeable. However, in some cases, it can make a big difference: [before] $ time git rev-list -1 origin Documentation/RelNotes/1.7.11.2.txt 8d141a1d562abb31f27f599dbf6e10a6c06ed73e real 0m0.301s user 0m0.280s sys 0m0.016s [after] $ time git rev-list -1 origin Documentation/RelNotes/1.7.11.2.txt 8d141a1d562abb31f27f599dbf6e10a6c06ed73e real 0m0.010s user 0m0.008s sys 0m0.000s Note that the output is produced almost instantaneously in the first case, and then git uselessly spends a long time looking for the next commit to touch that file (but there isn't one, and we traverse all the way down to the roots). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-07-13 07:50:23 +00:00
if (revs->max_count > 0)
revs->max_count--;
}
revision walker: Fix --boundary when limited This cleans up the boundary processing in the commit walker. It - rips out the boundary logic from the commit walker. Placing "negative" commits in the revs->commits list was Ok if all we cared about "boundary" was the UNINTERESTING limiting case, but conceptually it was wrong. - makes get_revision_1() function to walk the commits and return the results as if there is no funny postprocessing flags such as --reverse, --skip nor --max-count. - makes get_revision() function the postprocessing phase: If reverse is given, wait for get_revision_1() to give everything that it would normally give, and then reverse it before consuming. If skip is given, skip that many before going further. If max is given, stop when we gave out that many. Now that we are about to return one positive commit, mark the parents of that commit to be potential boundaries before returning, iff we are doing the boundary processing. Return the commit. - After get_revision() finishes giving out all the positive commits, if we are doing the boundary processing, we look at the parents that we marked as potential boundaries earlier, see if they are really boundaries, and give them out. It loses more code than it adds, even when the new gc_boundary() function, which is purely for early optimization, is counted. Note that this patch is purely for eyeballing and discussion only. It breaks git-bundle's verify logic because the logic does not use BOUNDARY_SHOW flag for its internal computation anymore. After we correct it not to attempt to affect the boundary processing by setting the BOUNDARY_SHOW flag, we can remove BOUNDARY_SHOW from revision.h and use that bit assignment for the new CHILD_SHOWN flag. Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-05 21:10:06 +00:00
if (c)
c->object.flags |= SHOWN;
if (!revs->boundary)
return c;
revision walker: Fix --boundary when limited This cleans up the boundary processing in the commit walker. It - rips out the boundary logic from the commit walker. Placing "negative" commits in the revs->commits list was Ok if all we cared about "boundary" was the UNINTERESTING limiting case, but conceptually it was wrong. - makes get_revision_1() function to walk the commits and return the results as if there is no funny postprocessing flags such as --reverse, --skip nor --max-count. - makes get_revision() function the postprocessing phase: If reverse is given, wait for get_revision_1() to give everything that it would normally give, and then reverse it before consuming. If skip is given, skip that many before going further. If max is given, stop when we gave out that many. Now that we are about to return one positive commit, mark the parents of that commit to be potential boundaries before returning, iff we are doing the boundary processing. Return the commit. - After get_revision() finishes giving out all the positive commits, if we are doing the boundary processing, we look at the parents that we marked as potential boundaries earlier, see if they are really boundaries, and give them out. It loses more code than it adds, even when the new gc_boundary() function, which is purely for early optimization, is counted. Note that this patch is purely for eyeballing and discussion only. It breaks git-bundle's verify logic because the logic does not use BOUNDARY_SHOW flag for its internal computation anymore. After we correct it not to attempt to affect the boundary processing by setting the BOUNDARY_SHOW flag, we can remove BOUNDARY_SHOW from revision.h and use that bit assignment for the new CHILD_SHOWN flag. Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-05 21:10:06 +00:00
if (!c) {
/*
* get_revision_1() runs out the commits, and
* we are done computing the boundaries.
* switch to boundary commits output mode.
*/
revs->boundary = 2;
/*
* Update revs->commits to contain the list of
* boundary commits.
*/
create_boundary_commit_list(revs);
return get_revision_internal(revs);
revision walker: Fix --boundary when limited This cleans up the boundary processing in the commit walker. It - rips out the boundary logic from the commit walker. Placing "negative" commits in the revs->commits list was Ok if all we cared about "boundary" was the UNINTERESTING limiting case, but conceptually it was wrong. - makes get_revision_1() function to walk the commits and return the results as if there is no funny postprocessing flags such as --reverse, --skip nor --max-count. - makes get_revision() function the postprocessing phase: If reverse is given, wait for get_revision_1() to give everything that it would normally give, and then reverse it before consuming. If skip is given, skip that many before going further. If max is given, stop when we gave out that many. Now that we are about to return one positive commit, mark the parents of that commit to be potential boundaries before returning, iff we are doing the boundary processing. Return the commit. - After get_revision() finishes giving out all the positive commits, if we are doing the boundary processing, we look at the parents that we marked as potential boundaries earlier, see if they are really boundaries, and give them out. It loses more code than it adds, even when the new gc_boundary() function, which is purely for early optimization, is counted. Note that this patch is purely for eyeballing and discussion only. It breaks git-bundle's verify logic because the logic does not use BOUNDARY_SHOW flag for its internal computation anymore. After we correct it not to attempt to affect the boundary processing by setting the BOUNDARY_SHOW flag, we can remove BOUNDARY_SHOW from revision.h and use that bit assignment for the new CHILD_SHOWN flag. Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-05 21:10:06 +00:00
}
/*
* boundary commits are the commits that are parents of the
* ones we got from get_revision_1() but they themselves are
* not returned from get_revision_1(). Before returning
* 'c', we need to mark its parents that they could be boundaries.
*/
for (l = c->parents; l; l = l->next) {
struct object *p;
p = &(l->item->object);
if (p->flags & (CHILD_SHOWN | SHOWN))
revision walker: Fix --boundary when limited This cleans up the boundary processing in the commit walker. It - rips out the boundary logic from the commit walker. Placing "negative" commits in the revs->commits list was Ok if all we cared about "boundary" was the UNINTERESTING limiting case, but conceptually it was wrong. - makes get_revision_1() function to walk the commits and return the results as if there is no funny postprocessing flags such as --reverse, --skip nor --max-count. - makes get_revision() function the postprocessing phase: If reverse is given, wait for get_revision_1() to give everything that it would normally give, and then reverse it before consuming. If skip is given, skip that many before going further. If max is given, stop when we gave out that many. Now that we are about to return one positive commit, mark the parents of that commit to be potential boundaries before returning, iff we are doing the boundary processing. Return the commit. - After get_revision() finishes giving out all the positive commits, if we are doing the boundary processing, we look at the parents that we marked as potential boundaries earlier, see if they are really boundaries, and give them out. It loses more code than it adds, even when the new gc_boundary() function, which is purely for early optimization, is counted. Note that this patch is purely for eyeballing and discussion only. It breaks git-bundle's verify logic because the logic does not use BOUNDARY_SHOW flag for its internal computation anymore. After we correct it not to attempt to affect the boundary processing by setting the BOUNDARY_SHOW flag, we can remove BOUNDARY_SHOW from revision.h and use that bit assignment for the new CHILD_SHOWN flag. Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-05 21:10:06 +00:00
continue;
p->flags |= CHILD_SHOWN;
gc_boundary(&revs->boundary_commits);
add_object_array(p, NULL, &revs->boundary_commits);
}
return c;
}
struct commit *get_revision(struct rev_info *revs)
{
struct commit *c;
struct commit_list *reversed;
if (revs->reverse) {
reversed = NULL;
while ((c = get_revision_internal(revs)))
commit_list_insert(c, &reversed);
revs->commits = reversed;
revs->reverse = 0;
revs->reverse_output_stage = 1;
}
if (revs->reverse_output_stage) {
c = pop_commit(&revs->commits);
if (revs->track_linear)
revs->linear = !!(c && c->object.flags & TRACK_LINEAR);
return c;
}
c = get_revision_internal(revs);
if (c && revs->graph)
graph_update(revs->graph, c);
if (!c) {
log: use true parents for diff even when rewriting When using pathspec filtering in combination with diff-based log output, parent simplification happens before the diff is computed. The diff is therefore against the *simplified* parents. This works okay, arguably by accident, in the normal case: simplification reduces to one parent as long as the commit is TREESAME to it. So the simplified parent of any given commit must have the same tree contents on the filtered paths as its true (unfiltered) parent. However, --full-diff breaks this guarantee, and indeed gives pretty spectacular results when comparing the output of git log --graph --stat ... git log --graph --full-diff --stat ... (--graph internally kicks in parent simplification, much like --parents). To fix it, store a copy of the parent list before simplification (in a slab) whenever --full-diff is in effect. Then use the stored parents instead of the simplified ones in the commit display code paths. The latter do not actually check for --full-diff to avoid duplicated code; they just grab the original parents if save_parents() has not been called for this revision walk. For ordinary commits it should be obvious that this is the right thing to do. Merge commits are a bit subtle. Observe that with default simplification, merge simplification is an all-or-nothing decision: either the merge is TREESAME to one parent and disappears, or it is different from all parents and the parent list remains intact. Redundant parents are not pruned, so the existing code also shows them as a merge. So if we do show a merge commit, the parent list just consists of the rewrite result on each parent. Running, e.g., --cc on this in --full-diff mode is not very useful: if any commits were skipped, some hunks will disagree with all sides of the merge (with one side, because commits were skipped; with the others, because they didn't have those changes in the first place). This triggers --cc showing these hunks spuriously. Therefore I believe that even for merge commits it is better to show the diffs wrt. the original parents. Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Helped-by: Junio C Hamano <gitster@pobox.com> Helped-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk> Signed-off-by: Thomas Rast <trast@inf.ethz.ch> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-31 20:13:20 +00:00
free_saved_parents(revs);
if (revs->previous_parents) {
free_commit_list(revs->previous_parents);
revs->previous_parents = NULL;
}
}
return c;
}
const char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
{
if (commit->object.flags & BOUNDARY)
return "-";
else if (commit->object.flags & UNINTERESTING)
return "^";
else if (commit->object.flags & PATCHSAME)
return "=";
else if (!revs || revs->left_right) {
if (commit->object.flags & SYMMETRIC_LEFT)
return "<";
else
return ">";
} else if (revs->graph)
return "*";
else if (revs->cherry_mark)
return "+";
return "";
}
void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
{
const char *mark = get_revision_mark(revs, commit);
if (!strlen(mark))
return;
fputs(mark, stdout);
putchar(' ');
}