git/commit-graph.c

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#include "git-compat-util.h"
#include "config.h"
#include "lockfile.h"
#include "pack.h"
#include "packfile.h"
#include "commit.h"
#include "object.h"
#include "refs.h"
#include "revision.h"
#include "sha1-lookup.h"
#include "commit-graph.h"
#include "object-store.h"
#include "alloc.h"
#include "hashmap.h"
#include "replace-object.h"
commit-graph write: add progress output Before this change the "commit-graph write" command didn't report any progress. On my machine this command takes more than 10 seconds to write the graph for linux.git, and around 1m30s on the 2015-04-03-1M-git.git[1] test repository (a test case for a large monorepository). Furthermore, since the gc.writeCommitGraph setting was added in d5d5d7b641 ("gc: automatically write commit-graph files", 2018-06-27), there was no indication at all from a "git gc" run that anything was different. This why one of the progress bars being added here uses start_progress() instead of start_delayed_progress(), so that it's guaranteed to be seen. E.g. on my tiny 867 commit dotfiles.git repository: $ git -c gc.writeCommitGraph=true gc Enumerating objects: 2821, done. [...] Computing commit graph generation numbers: 100% (867/867), done. On larger repositories, such as linux.git the delayed progress bar(s) will kick in, and we'll show what's going on instead of, as was previously happening, printing nothing while we write the graph: $ git -c gc.writeCommitGraph=true gc [...] Annotating commits in commit graph: 1565573, done. Computing commit graph generation numbers: 100% (782484/782484), done. Note that here we don't show "Finding commits for commit graph", this is because under "git gc" we seed the search with the commit references in the repository, and that set is too small to show any progress, but would e.g. on a smaller repo such as git.git with --stdin-commits: $ git rev-list --all | git -c gc.writeCommitGraph=true write --stdin-commits Finding commits for commit graph: 100% (162576/162576), done. Computing commit graph generation numbers: 100% (162576/162576), done. With --stdin-packs we don't show any estimation of how much is left to do. This is because we might be processing more than one pack. We could be less lazy here and show progress, either by detecting that we're only processing one pack, or by first looping over the packs to discover how many commits they have. I don't see the point in doing that work. So instead we get (on 2015-04-03-1M-git.git): $ echo pack-<HASH>.idx | git -c gc.writeCommitGraph=true --exec-path=$PWD commit-graph write --stdin-packs Finding commits for commit graph: 13064614, done. Annotating commits in commit graph: 3001341, done. Computing commit graph generation numbers: 100% (1000447/1000447), done. No GC mode uses --stdin-packs. It's what they use at Microsoft to manually compute the generation numbers for their collection of large packs which are never coalesced. The reason we need a "report_progress" variable passed down from "git gc" is so that we don't report this output when we're running in the process "git gc --auto" detaches from the terminal. Since we write the commit graph from the "git gc" process itself (as opposed to what we do with say the "git repack" phase), we'd end up writing the output to .git/gc.log and reporting it to the user next time as part of the "The last gc run reported the following[...]" error, see 329e6e8794 ("gc: save log from daemonized gc --auto and print it next time", 2015-09-19). So we must keep track of whether or not we're running in that demonized mode, and if so print no progress. See [2] and subsequent replies for a discussion of an approach not taken in compute_generation_numbers(). I.e. we're saying "Computing commit graph generation numbers", even though on an established history we're mostly skipping over all the work we did in the past. This is similar to the white lie we tell in the "Writing objects" phase (not all are objects being written). Always showing progress is considered more important than accuracy. I.e. on a repository like 2015-04-03-1M-git.git we'd hang for 6 seconds with no output on the second "git gc" if no changes were made to any objects in the interim if we'd take the approach in [2]. 1. https://github.com/avar/2015-04-03-1M-git 2. <c6960252-c095-fb2b-e0bc-b1e6bb261614@gmail.com> (https://public-inbox.org/git/c6960252-c095-fb2b-e0bc-b1e6bb261614@gmail.com/) Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17 15:33:35 +00:00
#include "progress.h"
#include "bloom.h"
#include "commit-slab.h"
#include "shallow.h"
#include "json-writer.h"
#include "trace2.h"
void git_test_write_commit_graph_or_die(void)
{
int flags = 0;
if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0))
return;
if (git_env_bool(GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS, 0))
flags = COMMIT_GRAPH_WRITE_BLOOM_FILTERS;
if (write_commit_graph_reachable(the_repository->objects->odb,
flags, NULL))
die("failed to write commit-graph under GIT_TEST_COMMIT_GRAPH");
}
#define GRAPH_SIGNATURE 0x43475048 /* "CGPH" */
#define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
#define GRAPH_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
#define GRAPH_CHUNKID_DATA 0x43444154 /* "CDAT" */
commit-graph: rename "large edges" to "extra edges" The optional 'Large Edge List' chunk of the commit graph file stores parent information for commits with more than two parents, and the names of most of the macros, variables, struct fields, and functions related to this chunk contain the term "large edges", e.g. write_graph_chunk_large_edges(). However, it's not a really great term, as the edges to the second and subsequent parents stored in this chunk are not any larger than the edges to the first and second parents stored in the "main" 'Commit Data' chunk. It's the number of edges, IOW number of parents, that is larger compared to non-merge and "regular" two-parent merge commits. And indeed, two functions in 'commit-graph.c' have a local variable called 'num_extra_edges' that refer to the same thing, and this "extra edges" term is much better at describing these edges. So let's rename all these references to "large edges" in macro, variable, function, etc. names to "extra edges". There is a GRAPH_OCTOPUS_EDGES_NEEDED macro as well; for the sake of consistency rename it to GRAPH_EXTRA_EDGES_NEEDED. We can do so safely without causing any incompatibility issues, because the term "large edges" doesn't come up in the file format itself in any form (the chunk's magic is {'E', 'D', 'G', 'E'}, there is no 'L' in there), but only in the specification text. The string "large edges", however, does come up in the output of 'git commit-graph read' and in tests looking at its input, but that command is explicitly documented as debugging aid, so we can change its output and the affected tests safely. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-19 20:21:13 +00:00
#define GRAPH_CHUNKID_EXTRAEDGES 0x45444745 /* "EDGE" */
#define GRAPH_CHUNKID_BLOOMINDEXES 0x42494458 /* "BIDX" */
#define GRAPH_CHUNKID_BLOOMDATA 0x42444154 /* "BDAT" */
#define GRAPH_CHUNKID_BASE 0x42415345 /* "BASE" */
#define MAX_NUM_CHUNKS 7
#define GRAPH_DATA_WIDTH (the_hash_algo->rawsz + 16)
#define GRAPH_VERSION_1 0x1
#define GRAPH_VERSION GRAPH_VERSION_1
commit-graph: rename "large edges" to "extra edges" The optional 'Large Edge List' chunk of the commit graph file stores parent information for commits with more than two parents, and the names of most of the macros, variables, struct fields, and functions related to this chunk contain the term "large edges", e.g. write_graph_chunk_large_edges(). However, it's not a really great term, as the edges to the second and subsequent parents stored in this chunk are not any larger than the edges to the first and second parents stored in the "main" 'Commit Data' chunk. It's the number of edges, IOW number of parents, that is larger compared to non-merge and "regular" two-parent merge commits. And indeed, two functions in 'commit-graph.c' have a local variable called 'num_extra_edges' that refer to the same thing, and this "extra edges" term is much better at describing these edges. So let's rename all these references to "large edges" in macro, variable, function, etc. names to "extra edges". There is a GRAPH_OCTOPUS_EDGES_NEEDED macro as well; for the sake of consistency rename it to GRAPH_EXTRA_EDGES_NEEDED. We can do so safely without causing any incompatibility issues, because the term "large edges" doesn't come up in the file format itself in any form (the chunk's magic is {'E', 'D', 'G', 'E'}, there is no 'L' in there), but only in the specification text. The string "large edges", however, does come up in the output of 'git commit-graph read' and in tests looking at its input, but that command is explicitly documented as debugging aid, so we can change its output and the affected tests safely. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-19 20:21:13 +00:00
#define GRAPH_EXTRA_EDGES_NEEDED 0x80000000
#define GRAPH_EDGE_LAST_MASK 0x7fffffff
#define GRAPH_PARENT_NONE 0x70000000
#define GRAPH_LAST_EDGE 0x80000000
#define GRAPH_HEADER_SIZE 8
#define GRAPH_FANOUT_SIZE (4 * 256)
#define GRAPH_CHUNKLOOKUP_WIDTH 12
#define GRAPH_MIN_SIZE (GRAPH_HEADER_SIZE + 4 * GRAPH_CHUNKLOOKUP_WIDTH \
+ GRAPH_FANOUT_SIZE + the_hash_algo->rawsz)
commit-graph: fix writing first commit-graph during fetch The previous commit includes a failing test for an issue around fetch.writeCommitGraph and fetching in a repo with a submodule. Here, we fix that bug and set the test to "test_expect_success". The problem arises with this set of commands when the remote repo at <url> has a submodule. Note that --recurse-submodules is not needed to demonstrate the bug. $ git clone <url> test $ cd test $ git -c fetch.writeCommitGraph=true fetch origin Computing commit graph generation numbers: 100% (12/12), done. BUG: commit-graph.c:886: missing parent <hash1> for commit <hash2> Aborted (core dumped) As an initial fix, I converted the code in builtin/fetch.c that calls write_commit_graph_reachable() to instead launch a "git commit-graph write --reachable --split" process. That code worked, but is not how we want the feature to work long-term. That test did demonstrate that the issue must be something to do with internal state of the 'git fetch' process. The write_commit_graph() method in commit-graph.c ensures the commits we plan to write are "closed under reachability" using close_reachable(). This method walks from the input commits, and uses the UNINTERESTING flag to mark which commits have already been visited. This allows the walk to take O(N) time, where N is the number of commits, instead of O(P) time, where P is the number of paths. (The number of paths can be exponential in the number of commits.) However, the UNINTERESTING flag is used in lots of places in the codebase. This flag usually means some barrier to stop a commit walk, such as in revision-walking to compare histories. It is not often cleared after the walk completes because the starting points of those walks do not have the UNINTERESTING flag, and clear_commit_marks() would stop immediately. This is happening during a 'git fetch' call with a remote. The fetch negotiation is comparing the remote refs with the local refs and marking some commits as UNINTERESTING. I tested running clear_commit_marks_many() to clear the UNINTERESTING flag inside close_reachable(), but the tips did not have the flag, so that did nothing. It turns out that the calculate_changed_submodule_paths() method is at fault. Thanks, Peff, for pointing out this detail! More specifically, for each submodule, the collect_changed_submodules() runs a revision walk to essentially do file-history on the list of submodules. That revision walk marks commits UNININTERESTING if they are simplified away by not changing the submodule. Instead, I finally arrived on the conclusion that I should use a flag that is not used in any other part of the code. In commit-reach.c, a number of flags were defined for commit walk algorithms. The REACHABLE flag seemed like it made the most sense, and it seems it was not actually used in the file. The REACHABLE flag was used in early versions of commit-reach.c, but was removed by 4fbcca4 (commit-reach: make can_all_from_reach... linear, 2018-07-20). Add the REACHABLE flag to commit-graph.c and use it instead of UNINTERESTING in close_reachable(). This fixes the bug in manual testing. Reported-by: Johannes Schindelin <johannes.schindelin@gmx.de> Helped-by: Jeff King <peff@peff.net> Helped-by: Szeder Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-24 13:40:42 +00:00
/* Remember to update object flag allocation in object.h */
#define REACHABLE (1u<<15)
/* Keep track of the order in which commits are added to our list. */
define_commit_slab(commit_pos, int);
static struct commit_pos commit_pos = COMMIT_SLAB_INIT(1, commit_pos);
static void set_commit_pos(struct repository *r, const struct object_id *oid)
{
static int32_t max_pos;
struct commit *commit = lookup_commit(r, oid);
if (!commit)
return; /* should never happen, but be lenient */
*commit_pos_at(&commit_pos, commit) = max_pos++;
}
static int commit_pos_cmp(const void *va, const void *vb)
{
const struct commit *a = *(const struct commit **)va;
const struct commit *b = *(const struct commit **)vb;
return commit_pos_at(&commit_pos, a) -
commit_pos_at(&commit_pos, b);
}
define_commit_slab(commit_graph_data_slab, struct commit_graph_data);
static struct commit_graph_data_slab commit_graph_data_slab =
COMMIT_SLAB_INIT(1, commit_graph_data_slab);
uint32_t commit_graph_position(const struct commit *c)
{
struct commit_graph_data *data =
commit_graph_data_slab_peek(&commit_graph_data_slab, c);
return data ? data->graph_pos : COMMIT_NOT_FROM_GRAPH;
}
uint32_t commit_graph_generation(const struct commit *c)
{
struct commit_graph_data *data =
commit_graph_data_slab_peek(&commit_graph_data_slab, c);
if (!data)
return GENERATION_NUMBER_INFINITY;
else if (data->graph_pos == COMMIT_NOT_FROM_GRAPH)
return GENERATION_NUMBER_INFINITY;
return data->generation;
}
static struct commit_graph_data *commit_graph_data_at(const struct commit *c)
{
unsigned int i, nth_slab;
struct commit_graph_data *data =
commit_graph_data_slab_peek(&commit_graph_data_slab, c);
if (data)
return data;
nth_slab = c->index / commit_graph_data_slab.slab_size;
data = commit_graph_data_slab_at(&commit_graph_data_slab, c);
/*
* commit-slab initializes elements with zero, overwrite this with
* COMMIT_NOT_FROM_GRAPH for graph_pos.
*
* We avoid initializing generation with checking if graph position
* is not COMMIT_NOT_FROM_GRAPH.
*/
for (i = 0; i < commit_graph_data_slab.slab_size; i++) {
commit_graph_data_slab.slab[nth_slab][i].graph_pos =
COMMIT_NOT_FROM_GRAPH;
}
return data;
}
static int commit_gen_cmp(const void *va, const void *vb)
{
const struct commit *a = *(const struct commit **)va;
const struct commit *b = *(const struct commit **)vb;
uint32_t generation_a = commit_graph_generation(a);
uint32_t generation_b = commit_graph_generation(b);
/* lower generation commits first */
if (generation_a < generation_b)
return -1;
else if (generation_a > generation_b)
return 1;
/* use date as a heuristic when generations are equal */
if (a->date < b->date)
return -1;
else if (a->date > b->date)
return 1;
return 0;
}
char *get_commit_graph_filename(struct object_directory *obj_dir)
{
return xstrfmt("%s/info/commit-graph", obj_dir->path);
}
commit-graph.c: remove path normalization, comparison As of the previous patch, all calls to 'commit-graph.c' functions which perform path normalization (for e.g., 'get_commit_graph_filename()') are of the form 'ctx->odb->path', which is always in normalized form. Now that there are no callers passing non-normalized paths to these functions, ensure that future callers are bound by the same restrictions by making these functions take a 'struct object_directory *' instead of a 'const char *'. To match, replace all calls with arguments of the form 'ctx->odb->path' with 'ctx->odb' To recover the path, functions that perform path manipulation simply use 'odb->path'. Further, avoid string comparisons with arguments of the form 'odb->path', and instead prefer raw pointer comparisons, which accomplish the same effect, but are far less brittle. This has a pleasant side-effect of making these functions much more robust to paths that cannot be normalized by 'normalize_path_copy()', i.e., because they are outside of the current working directory. For example, prior to this patch, Valgrind reports that the following uninitialized memory read [1]: $ ( cd t && GIT_DIR=../.git valgrind git rev-parse HEAD^ ) because 'normalize_path_copy()' can't normalize '../.git' (since it's relative to but above of the current working directory) [2]. By using a 'struct object_directory *' directly, 'get_commit_graph_filename()' does not need to normalize, because all paths are relative to the current working directory since they are always read from the '->path' of an object directory. [1]: https://lore.kernel.org/git/20191027042116.GA5801@sigill.intra.peff.net. [2]: The bug here is that 'get_commit_graph_filename()' returns the result of 'normalize_path_copy()' without checking the return value. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-03 21:18:02 +00:00
static char *get_split_graph_filename(struct object_directory *odb,
const char *oid_hex)
{
commit-graph.c: remove path normalization, comparison As of the previous patch, all calls to 'commit-graph.c' functions which perform path normalization (for e.g., 'get_commit_graph_filename()') are of the form 'ctx->odb->path', which is always in normalized form. Now that there are no callers passing non-normalized paths to these functions, ensure that future callers are bound by the same restrictions by making these functions take a 'struct object_directory *' instead of a 'const char *'. To match, replace all calls with arguments of the form 'ctx->odb->path' with 'ctx->odb' To recover the path, functions that perform path manipulation simply use 'odb->path'. Further, avoid string comparisons with arguments of the form 'odb->path', and instead prefer raw pointer comparisons, which accomplish the same effect, but are far less brittle. This has a pleasant side-effect of making these functions much more robust to paths that cannot be normalized by 'normalize_path_copy()', i.e., because they are outside of the current working directory. For example, prior to this patch, Valgrind reports that the following uninitialized memory read [1]: $ ( cd t && GIT_DIR=../.git valgrind git rev-parse HEAD^ ) because 'normalize_path_copy()' can't normalize '../.git' (since it's relative to but above of the current working directory) [2]. By using a 'struct object_directory *' directly, 'get_commit_graph_filename()' does not need to normalize, because all paths are relative to the current working directory since they are always read from the '->path' of an object directory. [1]: https://lore.kernel.org/git/20191027042116.GA5801@sigill.intra.peff.net. [2]: The bug here is that 'get_commit_graph_filename()' returns the result of 'normalize_path_copy()' without checking the return value. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-03 21:18:02 +00:00
return xstrfmt("%s/info/commit-graphs/graph-%s.graph", odb->path,
oid_hex);
}
char *get_commit_graph_chain_filename(struct object_directory *odb)
{
commit-graph.c: remove path normalization, comparison As of the previous patch, all calls to 'commit-graph.c' functions which perform path normalization (for e.g., 'get_commit_graph_filename()') are of the form 'ctx->odb->path', which is always in normalized form. Now that there are no callers passing non-normalized paths to these functions, ensure that future callers are bound by the same restrictions by making these functions take a 'struct object_directory *' instead of a 'const char *'. To match, replace all calls with arguments of the form 'ctx->odb->path' with 'ctx->odb' To recover the path, functions that perform path manipulation simply use 'odb->path'. Further, avoid string comparisons with arguments of the form 'odb->path', and instead prefer raw pointer comparisons, which accomplish the same effect, but are far less brittle. This has a pleasant side-effect of making these functions much more robust to paths that cannot be normalized by 'normalize_path_copy()', i.e., because they are outside of the current working directory. For example, prior to this patch, Valgrind reports that the following uninitialized memory read [1]: $ ( cd t && GIT_DIR=../.git valgrind git rev-parse HEAD^ ) because 'normalize_path_copy()' can't normalize '../.git' (since it's relative to but above of the current working directory) [2]. By using a 'struct object_directory *' directly, 'get_commit_graph_filename()' does not need to normalize, because all paths are relative to the current working directory since they are always read from the '->path' of an object directory. [1]: https://lore.kernel.org/git/20191027042116.GA5801@sigill.intra.peff.net. [2]: The bug here is that 'get_commit_graph_filename()' returns the result of 'normalize_path_copy()' without checking the return value. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-03 21:18:02 +00:00
return xstrfmt("%s/info/commit-graphs/commit-graph-chain", odb->path);
}
static uint8_t oid_version(void)
{
commit-graph: use the "hash version" byte The commit-graph format reserved a byte among the header of the file to store a "hash version". During the SHA-256 work, this was not modified because file formats are not necessarily intended to work across hash versions. If a repository has SHA-256 as its hash algorithm, it automatically up-shifts the lengths of object names in all necessary formats. However, since we have this byte available for adjusting the version, we can make the file formats more obviously incompatible instead of relying on other context from the repository. Update the oid_version() method in commit-graph.c to add a new value, 2, for sha-256. This automatically writes the new value in a SHA-256 repository _and_ verifies the value is correct. This is a breaking change relative to the current 'master' branch since 092b677 (Merge branch 'bc/sha-256-cvs-svn-updates', 2020-08-13) but it is not breaking relative to any released version of Git. The test impact is relatively minor: the output of 'test-tool read-graph' lists the header information, so those instances of '1' need to be replaced with a variable determined by GIT_TEST_DEFAULT_HASH. A more careful test is added that specifically creates a repository of each type then swaps the commit-graph files. The important value here is that the "git log" command succeeds while writing a message to stderr. Helped-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-17 14:04:47 +00:00
switch (hash_algo_by_ptr(the_hash_algo)) {
case GIT_HASH_SHA1:
return 1;
case GIT_HASH_SHA256:
return 2;
default:
die(_("invalid hash version"));
}
}
static struct commit_graph *alloc_commit_graph(void)
{
struct commit_graph *g = xcalloc(1, sizeof(*g));
return g;
}
extern int read_replace_refs;
static int commit_graph_compatible(struct repository *r)
{
if (!r->gitdir)
return 0;
if (read_replace_refs) {
prepare_replace_object(r);
if (hashmap_get_size(&r->objects->replace_map->map))
return 0;
}
prepare_commit_graft(r);
commit.c: don't persist substituted parents when unshallowing Since 37b9dcabfc (shallow.c: use '{commit,rollback}_shallow_file', 2020-04-22), Git knows how to reset stat-validity checks for the $GIT_DIR/shallow file, allowing it to change between a shallow and non-shallow state in the same process (e.g., in the case of 'git fetch --unshallow'). However, when $GIT_DIR/shallow changes, Git does not alter or remove any grafts (nor substituted parents) in memory. This comes up in a "git fetch --unshallow" with fetch.writeCommitGraph set to true. Ordinarily in a shallow repository (and before 37b9dcabfc, even in this case), commit_graph_compatible() would return false, indicating that the repository should not be used to write a commit-graphs (since commit-graph files cannot represent a shallow history). But since 37b9dcabfc, in an --unshallow operation that check succeeds. Thus even though the repository isn't shallow any longer (that is, we have all of the objects), the in-core representation of those objects still has munged parents at the shallow boundaries. When the commit-graph write proceeds, we use the incorrect parentage, producing wrong results. There are two ways for a user to work around this: either (1) set 'fetch.writeCommitGraph' to 'false', or (2) drop the commit-graph after unshallowing. One way to fix this would be to reset the parsed object pool entirely (flushing the cache and thus preventing subsequent reads from modifying their parents) after unshallowing. That would produce a problem when callers have a now-stale reference to the old pool, and so this patch implements a different approach. Instead, attach a new bit to the pool, 'substituted_parent', which indicates if the repository *ever* stored a commit which had its parents modified (i.e., the shallow boundary prior to unshallowing). This bit needs to be sticky because all reads subsequent to modifying a commit's parents are unreliable when unshallowing. Modify the check in 'commit_graph_compatible' to take this bit into account, and correctly avoid generating commit-graphs in this case, thus solving the bug. Helped-by: Derrick Stolee <dstolee@microsoft.com> Helped-by: Jonathan Nieder <jrnieder@gmail.com> Reported-by: Jay Conrod <jayconrod@google.com> Reviewed-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-08 21:10:53 +00:00
if (r->parsed_objects &&
(r->parsed_objects->grafts_nr || r->parsed_objects->substituted_parent))
return 0;
if (is_repository_shallow(r))
return 0;
return 1;
}
commit-graph: don't early exit(1) on e.g. "git status" Make the commit-graph loading code work as a library that returns an error code instead of calling exit(1) when the commit-graph is corrupt. This means that e.g. "status" will now report commit-graph corruption as an "error: [...]" at the top of its output, but then proceed to work normally. This required splitting up the load_commit_graph_one() function so that the code that deals with open()-ing and stat()-ing the graph can now be called independently as open_commit_graph(). This is needed because "commit-graph verify" where the graph doesn't exist isn't an error. See the third paragraph in 283e68c72f ("commit-graph: add 'verify' subcommand", 2018-06-27). There's a bug in that logic where we conflate the intended ENOENT with other errno values (e.g. EACCES), but this change doesn't address that. That'll be addressed in a follow-up change. I'm then splitting most of the logic out of load_commit_graph_one() into load_commit_graph_one_fd_st(), which allows for providing an existing file descriptor and stat information to the loading code. This isn't strictly needed, but it would be redundant and confusing to open() and stat() the file twice for some of the codepaths, this allows for calling open_commit_graph() followed by load_commit_graph_one_fd_st(). The "graph_file" still needs to be passed to that function for the the "graph file %s is too small" error message. This leaves load_commit_graph_one() unused by everything except the internal prepare_commit_graph_one() function, so let's mark it as "static". If someone needs it in the future we can remove the "static" attribute. I could also rewrite its sole remaining user ("prepare_commit_graph_one()") to use load_commit_graph_one_fd_st() instead, but let's leave it at this. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-25 12:08:30 +00:00
int open_commit_graph(const char *graph_file, int *fd, struct stat *st)
{
*fd = git_open(graph_file);
if (*fd < 0)
return 0;
if (fstat(*fd, st)) {
close(*fd);
return 0;
}
return 1;
}
struct commit_graph *load_commit_graph_one_fd_st(struct repository *r,
int fd, struct stat *st,
struct object_directory *odb)
{
void *graph_map;
size_t graph_size;
struct commit_graph *ret;
commit-graph: don't early exit(1) on e.g. "git status" Make the commit-graph loading code work as a library that returns an error code instead of calling exit(1) when the commit-graph is corrupt. This means that e.g. "status" will now report commit-graph corruption as an "error: [...]" at the top of its output, but then proceed to work normally. This required splitting up the load_commit_graph_one() function so that the code that deals with open()-ing and stat()-ing the graph can now be called independently as open_commit_graph(). This is needed because "commit-graph verify" where the graph doesn't exist isn't an error. See the third paragraph in 283e68c72f ("commit-graph: add 'verify' subcommand", 2018-06-27). There's a bug in that logic where we conflate the intended ENOENT with other errno values (e.g. EACCES), but this change doesn't address that. That'll be addressed in a follow-up change. I'm then splitting most of the logic out of load_commit_graph_one() into load_commit_graph_one_fd_st(), which allows for providing an existing file descriptor and stat information to the loading code. This isn't strictly needed, but it would be redundant and confusing to open() and stat() the file twice for some of the codepaths, this allows for calling open_commit_graph() followed by load_commit_graph_one_fd_st(). The "graph_file" still needs to be passed to that function for the the "graph file %s is too small" error message. This leaves load_commit_graph_one() unused by everything except the internal prepare_commit_graph_one() function, so let's mark it as "static". If someone needs it in the future we can remove the "static" attribute. I could also rewrite its sole remaining user ("prepare_commit_graph_one()") to use load_commit_graph_one_fd_st() instead, but let's leave it at this. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-25 12:08:30 +00:00
graph_size = xsize_t(st->st_size);
if (graph_size < GRAPH_MIN_SIZE) {
close(fd);
error(_("commit-graph file is too small"));
commit-graph: don't early exit(1) on e.g. "git status" Make the commit-graph loading code work as a library that returns an error code instead of calling exit(1) when the commit-graph is corrupt. This means that e.g. "status" will now report commit-graph corruption as an "error: [...]" at the top of its output, but then proceed to work normally. This required splitting up the load_commit_graph_one() function so that the code that deals with open()-ing and stat()-ing the graph can now be called independently as open_commit_graph(). This is needed because "commit-graph verify" where the graph doesn't exist isn't an error. See the third paragraph in 283e68c72f ("commit-graph: add 'verify' subcommand", 2018-06-27). There's a bug in that logic where we conflate the intended ENOENT with other errno values (e.g. EACCES), but this change doesn't address that. That'll be addressed in a follow-up change. I'm then splitting most of the logic out of load_commit_graph_one() into load_commit_graph_one_fd_st(), which allows for providing an existing file descriptor and stat information to the loading code. This isn't strictly needed, but it would be redundant and confusing to open() and stat() the file twice for some of the codepaths, this allows for calling open_commit_graph() followed by load_commit_graph_one_fd_st(). The "graph_file" still needs to be passed to that function for the the "graph file %s is too small" error message. This leaves load_commit_graph_one() unused by everything except the internal prepare_commit_graph_one() function, so let's mark it as "static". If someone needs it in the future we can remove the "static" attribute. I could also rewrite its sole remaining user ("prepare_commit_graph_one()") to use load_commit_graph_one_fd_st() instead, but let's leave it at this. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-25 12:08:30 +00:00
return NULL;
}
graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
ret = parse_commit_graph(r, graph_map, graph_size);
if (ret)
ret->odb = odb;
else
munmap(graph_map, graph_size);
return ret;
}
commit-graph: fix segfault on e.g. "git status" When core.commitGraph=true is set, various common commands now consult the commit graph. Because the commit-graph code is very trusting of its input data, it's possibly to construct a graph that'll cause an immediate segfault on e.g. "status" (and e.g. "log", "blame", ...). In some other cases where git immediately exits with a cryptic error about the graph being broken. The root cause of this is that while the "commit-graph verify" sub-command exhaustively verifies the graph, other users of the graph simply trust the graph, and will e.g. deference data found at certain offsets as pointers, causing segfaults. This change does the bare minimum to ensure that we don't segfault in the common fill_commit_in_graph() codepath called by e.g. setup_revisions(), to do this instrument the "commit-graph verify" tests to always check if "status" would subsequently segfault. This fixes the following tests which would previously segfault: not ok 50 - detect low chunk count not ok 51 - detect missing OID fanout chunk not ok 52 - detect missing OID lookup chunk not ok 53 - detect missing commit data chunk Those happened because with the commit-graph enabled setup_revisions() would eventually call fill_commit_in_graph(), where e.g. g->chunk_commit_data is used early as an offset (and will be 0x0). With this change we get far enough to detect that the graph is broken, and show an error instead. E.g.: $ git status; echo $? error: commit-graph is missing the Commit Data chunk 1 That also sucks, we should *warn* and not hard-fail "status" just because the commit-graph is corrupt, but fixing is left to a follow-up change. A side-effect of changing the reporting from graph_report() to error() is that we now have an "error: " prefix for these even for "commit-graph verify". Pseudo-diff before/after: $ git commit-graph verify -commit-graph is missing the Commit Data chunk +error: commit-graph is missing the Commit Data chunk Changing that is OK. Various errors it emits now early on are prefixed with "error: ", moving these over and changing the output doesn't break anything. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-25 12:08:29 +00:00
static int verify_commit_graph_lite(struct commit_graph *g)
{
/*
* Basic validation shared between parse_commit_graph()
* which'll be called every time the graph is used, and the
* much more expensive verify_commit_graph() used by
* "commit-graph verify".
*
* There should only be very basic checks here to ensure that
* we don't e.g. segfault in fill_commit_in_graph(), but
* because this is a very hot codepath nothing that e.g. loops
* over g->num_commits, or runs a checksum on the commit-graph
* itself.
*/
if (!g->chunk_oid_fanout) {
error("commit-graph is missing the OID Fanout chunk");
return 1;
}
if (!g->chunk_oid_lookup) {
error("commit-graph is missing the OID Lookup chunk");
return 1;
}
if (!g->chunk_commit_data) {
error("commit-graph is missing the Commit Data chunk");
return 1;
}
return 0;
}
struct commit_graph *parse_commit_graph(struct repository *r,
void *graph_map, size_t graph_size)
{
const unsigned char *data, *chunk_lookup;
uint32_t i;
struct commit_graph *graph;
uint64_t next_chunk_offset;
uint32_t graph_signature;
unsigned char graph_version, hash_version;
if (!graph_map)
return NULL;
if (graph_size < GRAPH_MIN_SIZE)
return NULL;
data = (const unsigned char *)graph_map;
graph_signature = get_be32(data);
if (graph_signature != GRAPH_SIGNATURE) {
error(_("commit-graph signature %X does not match signature %X"),
graph_signature, GRAPH_SIGNATURE);
return NULL;
}
graph_version = *(unsigned char*)(data + 4);
if (graph_version != GRAPH_VERSION) {
error(_("commit-graph version %X does not match version %X"),
graph_version, GRAPH_VERSION);
return NULL;
}
hash_version = *(unsigned char*)(data + 5);
if (hash_version != oid_version()) {
error(_("commit-graph hash version %X does not match version %X"),
hash_version, oid_version());
return NULL;
}
prepare_repo_settings(r);
graph = alloc_commit_graph();
graph->hash_len = the_hash_algo->rawsz;
graph->num_chunks = *(unsigned char*)(data + 6);
graph->data = graph_map;
graph->data_len = graph_size;
if (graph_size < GRAPH_HEADER_SIZE +
(graph->num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH +
GRAPH_FANOUT_SIZE + the_hash_algo->rawsz) {
error(_("commit-graph file is too small to hold %u chunks"),
graph->num_chunks);
free(graph);
return NULL;
}
chunk_lookup = data + 8;
next_chunk_offset = get_be64(chunk_lookup + 4);
for (i = 0; i < graph->num_chunks; i++) {
uint32_t chunk_id;
uint64_t chunk_offset = next_chunk_offset;
int chunk_repeated = 0;
chunk_id = get_be32(chunk_lookup + 0);
chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
next_chunk_offset = get_be64(chunk_lookup + 4);
if (chunk_offset > graph_size - the_hash_algo->rawsz) {
error(_("commit-graph improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
(uint32_t)chunk_offset);
goto free_and_return;
}
switch (chunk_id) {
case GRAPH_CHUNKID_OIDFANOUT:
if (graph->chunk_oid_fanout)
chunk_repeated = 1;
else
graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset);
break;
case GRAPH_CHUNKID_OIDLOOKUP:
if (graph->chunk_oid_lookup)
chunk_repeated = 1;
else {
graph->chunk_oid_lookup = data + chunk_offset;
graph->num_commits = (next_chunk_offset - chunk_offset)
/ graph->hash_len;
}
break;
case GRAPH_CHUNKID_DATA:
if (graph->chunk_commit_data)
chunk_repeated = 1;
else
graph->chunk_commit_data = data + chunk_offset;
break;
commit-graph: rename "large edges" to "extra edges" The optional 'Large Edge List' chunk of the commit graph file stores parent information for commits with more than two parents, and the names of most of the macros, variables, struct fields, and functions related to this chunk contain the term "large edges", e.g. write_graph_chunk_large_edges(). However, it's not a really great term, as the edges to the second and subsequent parents stored in this chunk are not any larger than the edges to the first and second parents stored in the "main" 'Commit Data' chunk. It's the number of edges, IOW number of parents, that is larger compared to non-merge and "regular" two-parent merge commits. And indeed, two functions in 'commit-graph.c' have a local variable called 'num_extra_edges' that refer to the same thing, and this "extra edges" term is much better at describing these edges. So let's rename all these references to "large edges" in macro, variable, function, etc. names to "extra edges". There is a GRAPH_OCTOPUS_EDGES_NEEDED macro as well; for the sake of consistency rename it to GRAPH_EXTRA_EDGES_NEEDED. We can do so safely without causing any incompatibility issues, because the term "large edges" doesn't come up in the file format itself in any form (the chunk's magic is {'E', 'D', 'G', 'E'}, there is no 'L' in there), but only in the specification text. The string "large edges", however, does come up in the output of 'git commit-graph read' and in tests looking at its input, but that command is explicitly documented as debugging aid, so we can change its output and the affected tests safely. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-19 20:21:13 +00:00
case GRAPH_CHUNKID_EXTRAEDGES:
if (graph->chunk_extra_edges)
chunk_repeated = 1;
else
commit-graph: rename "large edges" to "extra edges" The optional 'Large Edge List' chunk of the commit graph file stores parent information for commits with more than two parents, and the names of most of the macros, variables, struct fields, and functions related to this chunk contain the term "large edges", e.g. write_graph_chunk_large_edges(). However, it's not a really great term, as the edges to the second and subsequent parents stored in this chunk are not any larger than the edges to the first and second parents stored in the "main" 'Commit Data' chunk. It's the number of edges, IOW number of parents, that is larger compared to non-merge and "regular" two-parent merge commits. And indeed, two functions in 'commit-graph.c' have a local variable called 'num_extra_edges' that refer to the same thing, and this "extra edges" term is much better at describing these edges. So let's rename all these references to "large edges" in macro, variable, function, etc. names to "extra edges". There is a GRAPH_OCTOPUS_EDGES_NEEDED macro as well; for the sake of consistency rename it to GRAPH_EXTRA_EDGES_NEEDED. We can do so safely without causing any incompatibility issues, because the term "large edges" doesn't come up in the file format itself in any form (the chunk's magic is {'E', 'D', 'G', 'E'}, there is no 'L' in there), but only in the specification text. The string "large edges", however, does come up in the output of 'git commit-graph read' and in tests looking at its input, but that command is explicitly documented as debugging aid, so we can change its output and the affected tests safely. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-19 20:21:13 +00:00
graph->chunk_extra_edges = data + chunk_offset;
break;
case GRAPH_CHUNKID_BASE:
if (graph->chunk_base_graphs)
chunk_repeated = 1;
else
graph->chunk_base_graphs = data + chunk_offset;
break;
case GRAPH_CHUNKID_BLOOMINDEXES:
if (graph->chunk_bloom_indexes)
chunk_repeated = 1;
else if (r->settings.commit_graph_read_changed_paths)
graph->chunk_bloom_indexes = data + chunk_offset;
break;
case GRAPH_CHUNKID_BLOOMDATA:
if (graph->chunk_bloom_data)
chunk_repeated = 1;
else if (r->settings.commit_graph_read_changed_paths) {
uint32_t hash_version;
graph->chunk_bloom_data = data + chunk_offset;
hash_version = get_be32(data + chunk_offset);
if (hash_version != 1)
break;
graph->bloom_filter_settings = xmalloc(sizeof(struct bloom_filter_settings));
graph->bloom_filter_settings->hash_version = hash_version;
graph->bloom_filter_settings->num_hashes = get_be32(data + chunk_offset + 4);
graph->bloom_filter_settings->bits_per_entry = get_be32(data + chunk_offset + 8);
graph->bloom_filter_settings->max_changed_paths = DEFAULT_BLOOM_MAX_CHANGES;
}
break;
}
if (chunk_repeated) {
error(_("commit-graph chunk id %08x appears multiple times"), chunk_id);
goto free_and_return;
}
}
if (graph->chunk_bloom_indexes && graph->chunk_bloom_data) {
init_bloom_filters();
} else {
/* We need both the bloom chunks to exist together. Else ignore the data */
graph->chunk_bloom_indexes = NULL;
graph->chunk_bloom_data = NULL;
FREE_AND_NULL(graph->bloom_filter_settings);
}
hashcpy(graph->oid.hash, graph->data + graph->data_len - graph->hash_len);
if (verify_commit_graph_lite(graph))
goto free_and_return;
commit-graph: fix segfault on e.g. "git status" When core.commitGraph=true is set, various common commands now consult the commit graph. Because the commit-graph code is very trusting of its input data, it's possibly to construct a graph that'll cause an immediate segfault on e.g. "status" (and e.g. "log", "blame", ...). In some other cases where git immediately exits with a cryptic error about the graph being broken. The root cause of this is that while the "commit-graph verify" sub-command exhaustively verifies the graph, other users of the graph simply trust the graph, and will e.g. deference data found at certain offsets as pointers, causing segfaults. This change does the bare minimum to ensure that we don't segfault in the common fill_commit_in_graph() codepath called by e.g. setup_revisions(), to do this instrument the "commit-graph verify" tests to always check if "status" would subsequently segfault. This fixes the following tests which would previously segfault: not ok 50 - detect low chunk count not ok 51 - detect missing OID fanout chunk not ok 52 - detect missing OID lookup chunk not ok 53 - detect missing commit data chunk Those happened because with the commit-graph enabled setup_revisions() would eventually call fill_commit_in_graph(), where e.g. g->chunk_commit_data is used early as an offset (and will be 0x0). With this change we get far enough to detect that the graph is broken, and show an error instead. E.g.: $ git status; echo $? error: commit-graph is missing the Commit Data chunk 1 That also sucks, we should *warn* and not hard-fail "status" just because the commit-graph is corrupt, but fixing is left to a follow-up change. A side-effect of changing the reporting from graph_report() to error() is that we now have an "error: " prefix for these even for "commit-graph verify". Pseudo-diff before/after: $ git commit-graph verify -commit-graph is missing the Commit Data chunk +error: commit-graph is missing the Commit Data chunk Changing that is OK. Various errors it emits now early on are prefixed with "error: ", moving these over and changing the output doesn't break anything. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-25 12:08:29 +00:00
return graph;
free_and_return:
free(graph->bloom_filter_settings);
free(graph);
return NULL;
}
static struct commit_graph *load_commit_graph_one(struct repository *r,
const char *graph_file,
struct object_directory *odb)
commit-graph: don't early exit(1) on e.g. "git status" Make the commit-graph loading code work as a library that returns an error code instead of calling exit(1) when the commit-graph is corrupt. This means that e.g. "status" will now report commit-graph corruption as an "error: [...]" at the top of its output, but then proceed to work normally. This required splitting up the load_commit_graph_one() function so that the code that deals with open()-ing and stat()-ing the graph can now be called independently as open_commit_graph(). This is needed because "commit-graph verify" where the graph doesn't exist isn't an error. See the third paragraph in 283e68c72f ("commit-graph: add 'verify' subcommand", 2018-06-27). There's a bug in that logic where we conflate the intended ENOENT with other errno values (e.g. EACCES), but this change doesn't address that. That'll be addressed in a follow-up change. I'm then splitting most of the logic out of load_commit_graph_one() into load_commit_graph_one_fd_st(), which allows for providing an existing file descriptor and stat information to the loading code. This isn't strictly needed, but it would be redundant and confusing to open() and stat() the file twice for some of the codepaths, this allows for calling open_commit_graph() followed by load_commit_graph_one_fd_st(). The "graph_file" still needs to be passed to that function for the the "graph file %s is too small" error message. This leaves load_commit_graph_one() unused by everything except the internal prepare_commit_graph_one() function, so let's mark it as "static". If someone needs it in the future we can remove the "static" attribute. I could also rewrite its sole remaining user ("prepare_commit_graph_one()") to use load_commit_graph_one_fd_st() instead, but let's leave it at this. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-25 12:08:30 +00:00
{
struct stat st;
int fd;
struct commit_graph *g;
commit-graph: don't early exit(1) on e.g. "git status" Make the commit-graph loading code work as a library that returns an error code instead of calling exit(1) when the commit-graph is corrupt. This means that e.g. "status" will now report commit-graph corruption as an "error: [...]" at the top of its output, but then proceed to work normally. This required splitting up the load_commit_graph_one() function so that the code that deals with open()-ing and stat()-ing the graph can now be called independently as open_commit_graph(). This is needed because "commit-graph verify" where the graph doesn't exist isn't an error. See the third paragraph in 283e68c72f ("commit-graph: add 'verify' subcommand", 2018-06-27). There's a bug in that logic where we conflate the intended ENOENT with other errno values (e.g. EACCES), but this change doesn't address that. That'll be addressed in a follow-up change. I'm then splitting most of the logic out of load_commit_graph_one() into load_commit_graph_one_fd_st(), which allows for providing an existing file descriptor and stat information to the loading code. This isn't strictly needed, but it would be redundant and confusing to open() and stat() the file twice for some of the codepaths, this allows for calling open_commit_graph() followed by load_commit_graph_one_fd_st(). The "graph_file" still needs to be passed to that function for the the "graph file %s is too small" error message. This leaves load_commit_graph_one() unused by everything except the internal prepare_commit_graph_one() function, so let's mark it as "static". If someone needs it in the future we can remove the "static" attribute. I could also rewrite its sole remaining user ("prepare_commit_graph_one()") to use load_commit_graph_one_fd_st() instead, but let's leave it at this. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-25 12:08:30 +00:00
int open_ok = open_commit_graph(graph_file, &fd, &st);
if (!open_ok)
return NULL;
g = load_commit_graph_one_fd_st(r, fd, &st, odb);
if (g)
g->filename = xstrdup(graph_file);
return g;
commit-graph: don't early exit(1) on e.g. "git status" Make the commit-graph loading code work as a library that returns an error code instead of calling exit(1) when the commit-graph is corrupt. This means that e.g. "status" will now report commit-graph corruption as an "error: [...]" at the top of its output, but then proceed to work normally. This required splitting up the load_commit_graph_one() function so that the code that deals with open()-ing and stat()-ing the graph can now be called independently as open_commit_graph(). This is needed because "commit-graph verify" where the graph doesn't exist isn't an error. See the third paragraph in 283e68c72f ("commit-graph: add 'verify' subcommand", 2018-06-27). There's a bug in that logic where we conflate the intended ENOENT with other errno values (e.g. EACCES), but this change doesn't address that. That'll be addressed in a follow-up change. I'm then splitting most of the logic out of load_commit_graph_one() into load_commit_graph_one_fd_st(), which allows for providing an existing file descriptor and stat information to the loading code. This isn't strictly needed, but it would be redundant and confusing to open() and stat() the file twice for some of the codepaths, this allows for calling open_commit_graph() followed by load_commit_graph_one_fd_st(). The "graph_file" still needs to be passed to that function for the the "graph file %s is too small" error message. This leaves load_commit_graph_one() unused by everything except the internal prepare_commit_graph_one() function, so let's mark it as "static". If someone needs it in the future we can remove the "static" attribute. I could also rewrite its sole remaining user ("prepare_commit_graph_one()") to use load_commit_graph_one_fd_st() instead, but let's leave it at this. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-25 12:08:30 +00:00
}
static struct commit_graph *load_commit_graph_v1(struct repository *r,
struct object_directory *odb)
{
commit-graph.c: remove path normalization, comparison As of the previous patch, all calls to 'commit-graph.c' functions which perform path normalization (for e.g., 'get_commit_graph_filename()') are of the form 'ctx->odb->path', which is always in normalized form. Now that there are no callers passing non-normalized paths to these functions, ensure that future callers are bound by the same restrictions by making these functions take a 'struct object_directory *' instead of a 'const char *'. To match, replace all calls with arguments of the form 'ctx->odb->path' with 'ctx->odb' To recover the path, functions that perform path manipulation simply use 'odb->path'. Further, avoid string comparisons with arguments of the form 'odb->path', and instead prefer raw pointer comparisons, which accomplish the same effect, but are far less brittle. This has a pleasant side-effect of making these functions much more robust to paths that cannot be normalized by 'normalize_path_copy()', i.e., because they are outside of the current working directory. For example, prior to this patch, Valgrind reports that the following uninitialized memory read [1]: $ ( cd t && GIT_DIR=../.git valgrind git rev-parse HEAD^ ) because 'normalize_path_copy()' can't normalize '../.git' (since it's relative to but above of the current working directory) [2]. By using a 'struct object_directory *' directly, 'get_commit_graph_filename()' does not need to normalize, because all paths are relative to the current working directory since they are always read from the '->path' of an object directory. [1]: https://lore.kernel.org/git/20191027042116.GA5801@sigill.intra.peff.net. [2]: The bug here is that 'get_commit_graph_filename()' returns the result of 'normalize_path_copy()' without checking the return value. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-03 21:18:02 +00:00
char *graph_name = get_commit_graph_filename(odb);
struct commit_graph *g = load_commit_graph_one(r, graph_name, odb);
free(graph_name);
return g;
}
static int add_graph_to_chain(struct commit_graph *g,
struct commit_graph *chain,
struct object_id *oids,
int n)
{
struct commit_graph *cur_g = chain;
if (n && !g->chunk_base_graphs) {
warning(_("commit-graph has no base graphs chunk"));
return 0;
}
while (n) {
n--;
if (!cur_g ||
!oideq(&oids[n], &cur_g->oid) ||
!hasheq(oids[n].hash, g->chunk_base_graphs + g->hash_len * n)) {
warning(_("commit-graph chain does not match"));
return 0;
}
cur_g = cur_g->base_graph;
}
g->base_graph = chain;
if (chain)
g->num_commits_in_base = chain->num_commits + chain->num_commits_in_base;
return 1;
}
static struct commit_graph *load_commit_graph_chain(struct repository *r,
struct object_directory *odb)
{
struct commit_graph *graph_chain = NULL;
struct strbuf line = STRBUF_INIT;
struct stat st;
struct object_id *oids;
int i = 0, valid = 1, count;
char *chain_name = get_commit_graph_chain_filename(odb);
FILE *fp;
int stat_res;
fp = fopen(chain_name, "r");
stat_res = stat(chain_name, &st);
free(chain_name);
if (!fp ||
stat_res ||
st.st_size <= the_hash_algo->hexsz)
return NULL;
count = st.st_size / (the_hash_algo->hexsz + 1);
oids = xcalloc(count, sizeof(struct object_id));
prepare_alt_odb(r);
for (i = 0; i < count; i++) {
struct object_directory *odb;
if (strbuf_getline_lf(&line, fp) == EOF)
break;
if (get_oid_hex(line.buf, &oids[i])) {
warning(_("invalid commit-graph chain: line '%s' not a hash"),
line.buf);
valid = 0;
break;
}
valid = 0;
for (odb = r->objects->odb; odb; odb = odb->next) {
commit-graph.c: remove path normalization, comparison As of the previous patch, all calls to 'commit-graph.c' functions which perform path normalization (for e.g., 'get_commit_graph_filename()') are of the form 'ctx->odb->path', which is always in normalized form. Now that there are no callers passing non-normalized paths to these functions, ensure that future callers are bound by the same restrictions by making these functions take a 'struct object_directory *' instead of a 'const char *'. To match, replace all calls with arguments of the form 'ctx->odb->path' with 'ctx->odb' To recover the path, functions that perform path manipulation simply use 'odb->path'. Further, avoid string comparisons with arguments of the form 'odb->path', and instead prefer raw pointer comparisons, which accomplish the same effect, but are far less brittle. This has a pleasant side-effect of making these functions much more robust to paths that cannot be normalized by 'normalize_path_copy()', i.e., because they are outside of the current working directory. For example, prior to this patch, Valgrind reports that the following uninitialized memory read [1]: $ ( cd t && GIT_DIR=../.git valgrind git rev-parse HEAD^ ) because 'normalize_path_copy()' can't normalize '../.git' (since it's relative to but above of the current working directory) [2]. By using a 'struct object_directory *' directly, 'get_commit_graph_filename()' does not need to normalize, because all paths are relative to the current working directory since they are always read from the '->path' of an object directory. [1]: https://lore.kernel.org/git/20191027042116.GA5801@sigill.intra.peff.net. [2]: The bug here is that 'get_commit_graph_filename()' returns the result of 'normalize_path_copy()' without checking the return value. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-03 21:18:02 +00:00
char *graph_name = get_split_graph_filename(odb, line.buf);
struct commit_graph *g = load_commit_graph_one(r, graph_name, odb);
free(graph_name);
if (g) {
if (add_graph_to_chain(g, graph_chain, oids, i)) {
graph_chain = g;
valid = 1;
}
break;
}
}
if (!valid) {
warning(_("unable to find all commit-graph files"));
break;
}
}
free(oids);
fclose(fp);
strbuf_release(&line);
return graph_chain;
}
struct commit_graph *read_commit_graph_one(struct repository *r,
struct object_directory *odb)
{
struct commit_graph *g = load_commit_graph_v1(r, odb);
if (!g)
g = load_commit_graph_chain(r, odb);
return g;
commit-graph: don't early exit(1) on e.g. "git status" Make the commit-graph loading code work as a library that returns an error code instead of calling exit(1) when the commit-graph is corrupt. This means that e.g. "status" will now report commit-graph corruption as an "error: [...]" at the top of its output, but then proceed to work normally. This required splitting up the load_commit_graph_one() function so that the code that deals with open()-ing and stat()-ing the graph can now be called independently as open_commit_graph(). This is needed because "commit-graph verify" where the graph doesn't exist isn't an error. See the third paragraph in 283e68c72f ("commit-graph: add 'verify' subcommand", 2018-06-27). There's a bug in that logic where we conflate the intended ENOENT with other errno values (e.g. EACCES), but this change doesn't address that. That'll be addressed in a follow-up change. I'm then splitting most of the logic out of load_commit_graph_one() into load_commit_graph_one_fd_st(), which allows for providing an existing file descriptor and stat information to the loading code. This isn't strictly needed, but it would be redundant and confusing to open() and stat() the file twice for some of the codepaths, this allows for calling open_commit_graph() followed by load_commit_graph_one_fd_st(). The "graph_file" still needs to be passed to that function for the the "graph file %s is too small" error message. This leaves load_commit_graph_one() unused by everything except the internal prepare_commit_graph_one() function, so let's mark it as "static". If someone needs it in the future we can remove the "static" attribute. I could also rewrite its sole remaining user ("prepare_commit_graph_one()") to use load_commit_graph_one_fd_st() instead, but let's leave it at this. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-25 12:08:30 +00:00
}
static void prepare_commit_graph_one(struct repository *r,
struct object_directory *odb)
{
if (r->objects->commit_graph)
return;
r->objects->commit_graph = read_commit_graph_one(r, odb);
}
/*
* Return 1 if commit_graph is non-NULL, and 0 otherwise.
*
* On the first invocation, this function attempts to load the commit
* graph if the_repository is configured to have one.
*/
static int prepare_commit_graph(struct repository *r)
{
struct object_directory *odb;
upload-pack: disable commit graph more gently for shallow traversal When the client has asked for certain shallow options like "deepen-since", we do a custom rev-list walk that pretends to be shallow. Before doing so, we have to disable the commit-graph, since it is not compatible with the shallow view of the repository. That's handled by 829a321569 (commit-graph: close_commit_graph before shallow walk, 2018-08-20). That commit literally closes and frees our repo->objects->commit_graph struct. That creates an interesting problem for commits that have _already_ been parsed using the commit graph. Their commit->object.parsed flag is set, their commit->graph_pos is set, but their commit->maybe_tree may still be NULL. When somebody later calls repo_get_commit_tree(), we see that we haven't loaded the tree oid yet and try to get it from the commit graph. But since it has been freed, we segfault! So the root of the issue is a data dependency between the commit's lazy-load of the tree oid and the fact that the commit graph can go away mid-process. How can we resolve it? There are a couple of general approaches: 1. The obvious answer is to avoid loading the tree from the graph when we see that it's NULL. But then what do we return for the tree oid? If we return NULL, our caller in do_traverse() will rightly complain that we have no tree. We'd have to fallback to loading the actual commit object and re-parsing it. That requires teaching parse_commit_buffer() to understand re-parsing (i.e., not starting from a clean slate and not leaking any allocated bits like parent list pointers). 2. When we close the commit graph, walk through the set of in-memory objects and clear any graph_pos pointers. But this means we also have to "unparse" any such commits so that we know they still need to open the commit object to fill in their trees. So it's no less complicated than (1), and is more expensive (since we clear objects we might not later need). 3. Stop freeing the commit-graph struct. Continue to let it be used for lazy-loads of tree oids, but let upload-pack specify that it shouldn't be used for further commit parsing. 4. Push the whole shallow rev-list out to its own sub-process, with the commit-graph disabled from the start, giving it a clean memory space to work from. I've chosen (3) here. Options (1) and (2) would work, but are non-trivial to implement. Option (4) is more expensive, and I'm not sure how complicated it is (shelling out for the actual rev-list part is easy, but we do then parse the resulting commits internally, and I'm not clear which parts need to be handling shallow-ness). The new test in t5500 triggers this segfault, but see the comments there for how horribly intimate it has to be with how both upload-pack and commit graphs work. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-09-12 14:44:45 +00:00
/*
* This must come before the "already attempted?" check below, because
* we want to disable even an already-loaded graph file.
*/
if (r->commit_graph_disabled)
return 0;
commit-graph write: don't die if the existing graph is corrupt When the commit-graph is written we end up calling parse_commit(). This will in turn invoke code that'll consult the existing commit-graph about the commit, if the graph is corrupted we die. We thus get into a state where a failing "commit-graph verify" can't be followed-up with a "commit-graph write" if core.commitGraph=true is set, the graph either needs to be manually removed to proceed, or core.commitGraph needs to be set to "false". Change the "commit-graph write" codepath to use a new parse_commit_no_graph() helper instead of parse_commit() to avoid this. The latter will call repo_parse_commit_internal() with use_commit_graph=1 as seen in 177722b344 ("commit: integrate commit graph with commit parsing", 2018-04-10). Not using the old graph at all slows down the writing of the new graph by some small amount, but is a sensible way to prevent an error in the existing commit-graph from spreading. Just fixing the current issue would be likely to result in code that's inadvertently broken in the future. New code might use the commit-graph at a distance. To detect such cases introduce a "GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD" setting used when we do our corruption tests, and test that a "write/verify" combo works after every one of our current test cases where we now detect commit-graph corruption. Some of the code changes here might be strictly unnecessary, e.g. I was unable to find cases where the parse_commit() called from write_graph_chunk_data() didn't exit early due to "item->object.parsed" being true in repo_parse_commit_internal() (before the use_commit_graph=1 has any effect). But let's also convert those cases for good measure, we do not have exhaustive tests for all possible types of commit-graph corruption. This might need to be re-visited if we learn to write the commit-graph incrementally, but probably not. Hopefully we'll just start by finding out what commits we have in total, then read the old graph(s) to see what they cover, and finally write a new graph file with everything that's missing. In that case the new graph writing code just needs to continue to use e.g. a parse_commit() that doesn't consult the existing commit-graphs. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-25 12:08:33 +00:00
if (r->objects->commit_graph_attempted)
return !!r->objects->commit_graph;
r->objects->commit_graph_attempted = 1;
prepare_repo_settings(r);
if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
r->settings.core_commit_graph != 1)
/*
* This repository is not configured to use commit graphs, so
* do not load one. (But report commit_graph_attempted anyway
* so that commit graph loading is not attempted again for this
* repository.)
*/
return 0;
if (!commit_graph_compatible(r))
return 0;
prepare_alt_odb(r);
sha1-file: use an object_directory for the main object dir Our handling of alternate object directories is needlessly different from the main object directory. As a result, many places in the code basically look like this: do_something(r->objects->objdir); for (odb = r->objects->alt_odb_list; odb; odb = odb->next) do_something(odb->path); That gets annoying when do_something() is non-trivial, and we've resorted to gross hacks like creating fake alternates (see find_short_object_filename()). Instead, let's give each raw_object_store a unified list of object_directory structs. The first will be the main store, and everything after is an alternate. Very few callers even care about the distinction, and can just loop over the whole list (and those who care can just treat the first element differently). A few observations: - we don't need r->objects->objectdir anymore, and can just mechanically convert that to r->objects->odb->path - object_directory's path field needs to become a real pointer rather than a FLEX_ARRAY, in order to fill it with expand_base_dir() - we'll call prepare_alt_odb() earlier in many functions (i.e., outside of the loop). This may result in us calling it even when our function would be satisfied looking only at the main odb. But this doesn't matter in practice. It's not a very expensive operation in the first place, and in the majority of cases it will be a noop. We call it already (and cache its results) in prepare_packed_git(), and we'll generally check packs before loose objects. So essentially every program is going to call it immediately once per program. Arguably we should just prepare_alt_odb() immediately upon setting up the repository's object directory, which would save us sprinkling calls throughout the code base (and forgetting to do so has been a source of subtle bugs in the past). But I've stopped short of that here, since there are already a lot of other moving parts in this patch. - Most call sites just get shorter. The check_and_freshen() functions are an exception, because they have entry points to handle local and nonlocal directories separately. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-12 14:50:39 +00:00
for (odb = r->objects->odb;
!r->objects->commit_graph && odb;
odb = odb->next)
prepare_commit_graph_one(r, odb);
return !!r->objects->commit_graph;
}
commit-reach: use can_all_from_reach The is_descendant_of method previously used in_merge_bases() to check if the commit can reach any of the commits in the provided list. This had two performance problems: 1. The performance is quadratic in worst-case. 2. A single in_merge_bases() call requires walking beyond the target commit in order to find the full set of boundary commits that may be merge-bases. The can_all_from_reach method avoids this quadratic behavior and can limit the search beyond the target commits using generation numbers. It requires a small prototype adjustment to stop using commit-date as a cutoff, as that optimization is no longer appropriate here. Since in_merge_bases() uses paint_down_to_common(), is_descendant_of() naturally found cutoffs to avoid walking the entire commit graph. Since we want to always return the correct result, we cannot use the min_commit_date cutoff in can_all_from_reach. We then rely on generation numbers to provide the cutoff. Since not all repos will have a commit-graph file, nor will we always have generation numbers computed for a commit-graph file, create a new method, generation_numbers_enabled(), that checks for a commit-graph file and sees if the first commit in the file has a non-zero generation number. In the case that we do not have generation numbers, use the old logic for is_descendant_of(). Performance was meausured on a copy of the Linux repository using the 'test-tool reach is_descendant_of' command using this input: A:v4.9 X:v4.10 X:v4.11 X:v4.12 X:v4.13 X:v4.14 X:v4.15 X:v4.16 X:v4.17 X.v3.0 Note that this input is tailored to demonstrate the quadratic nature of the previous method, as it will compute merge-bases for v4.9 versus all of the later versions before checking against v4.1. Before: 0.26 s After: 0.21 s Since we previously used the is_descendant_of method in the ref_newer method, we also measured performance there using 'test-tool reach ref_newer' with this input: A:v4.9 B:v3.19 Before: 0.10 s After: 0.08 s By adding a new commit with parent v3.19, we test the non-reachable case of ref_newer: Before: 0.09 s After: 0.08 s Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 16:33:30 +00:00
int generation_numbers_enabled(struct repository *r)
{
uint32_t first_generation;
struct commit_graph *g;
if (!prepare_commit_graph(r))
return 0;
g = r->objects->commit_graph;
if (!g->num_commits)
return 0;
first_generation = get_be32(g->chunk_commit_data +
g->hash_len + 8) >> 2;
return !!first_generation;
}
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
struct bloom_filter_settings *get_bloom_filter_settings(struct repository *r)
{
struct commit_graph *g = r->objects->commit_graph;
while (g) {
if (g->bloom_filter_settings)
return g->bloom_filter_settings;
g = g->base_graph;
}
return NULL;
}
static void close_commit_graph_one(struct commit_graph *g)
{
if (!g)
return;
close_commit_graph_one(g->base_graph);
free_commit_graph(g);
}
void close_commit_graph(struct raw_object_store *o)
{
close_commit_graph_one(o->commit_graph);
o->commit_graph = NULL;
}
static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
{
return bsearch_hash(oid->hash, g->chunk_oid_fanout,
g->chunk_oid_lookup, g->hash_len, pos);
}
static void load_oid_from_graph(struct commit_graph *g,
uint32_t pos,
struct object_id *oid)
{
uint32_t lex_index;
while (g && pos < g->num_commits_in_base)
g = g->base_graph;
if (!g)
BUG("NULL commit-graph");
if (pos >= g->num_commits + g->num_commits_in_base)
die(_("invalid commit position. commit-graph is likely corrupt"));
lex_index = pos - g->num_commits_in_base;
hashcpy(oid->hash, g->chunk_oid_lookup + g->hash_len * lex_index);
}
static struct commit_list **insert_parent_or_die(struct repository *r,
struct commit_graph *g,
uint32_t pos,
struct commit_list **pptr)
{
struct commit *c;
struct object_id oid;
if (pos >= g->num_commits + g->num_commits_in_base)
die("invalid parent position %"PRIu32, pos);
load_oid_from_graph(g, pos, &oid);
c = lookup_commit(r, &oid);
if (!c)
die(_("could not find commit %s"), oid_to_hex(&oid));
commit_graph_data_at(c)->graph_pos = pos;
return &commit_list_insert(c, pptr)->next;
}
static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
{
const unsigned char *commit_data;
struct commit_graph_data *graph_data;
uint32_t lex_index;
while (pos < g->num_commits_in_base)
g = g->base_graph;
lex_index = pos - g->num_commits_in_base;
commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * lex_index;
graph_data = commit_graph_data_at(item);
graph_data->graph_pos = pos;
graph_data->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
}
static inline void set_commit_tree(struct commit *c, struct tree *t)
{
c->maybe_tree = t;
}
static int fill_commit_in_graph(struct repository *r,
struct commit *item,
struct commit_graph *g, uint32_t pos)
{
uint32_t edge_value;
uint32_t *parent_data_ptr;
uint64_t date_low, date_high;
struct commit_list **pptr;
struct commit_graph_data *graph_data;
const unsigned char *commit_data;
uint32_t lex_index;
while (pos < g->num_commits_in_base)
g = g->base_graph;
if (pos >= g->num_commits + g->num_commits_in_base)
die(_("invalid commit position. commit-graph is likely corrupt"));
/*
* Store the "full" position, but then use the
* "local" position for the rest of the calculation.
*/
graph_data = commit_graph_data_at(item);
graph_data->graph_pos = pos;
lex_index = pos - g->num_commits_in_base;
commit_data = g->chunk_commit_data + (g->hash_len + 16) * lex_index;
item->object.parsed = 1;
set_commit_tree(item, NULL);
date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
date_low = get_be32(commit_data + g->hash_len + 12);
item->date = (timestamp_t)((date_high << 32) | date_low);
graph_data->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
pptr = &item->parents;
edge_value = get_be32(commit_data + g->hash_len);
if (edge_value == GRAPH_PARENT_NONE)
return 1;
pptr = insert_parent_or_die(r, g, edge_value, pptr);
edge_value = get_be32(commit_data + g->hash_len + 4);
if (edge_value == GRAPH_PARENT_NONE)
return 1;
commit-graph: rename "large edges" to "extra edges" The optional 'Large Edge List' chunk of the commit graph file stores parent information for commits with more than two parents, and the names of most of the macros, variables, struct fields, and functions related to this chunk contain the term "large edges", e.g. write_graph_chunk_large_edges(). However, it's not a really great term, as the edges to the second and subsequent parents stored in this chunk are not any larger than the edges to the first and second parents stored in the "main" 'Commit Data' chunk. It's the number of edges, IOW number of parents, that is larger compared to non-merge and "regular" two-parent merge commits. And indeed, two functions in 'commit-graph.c' have a local variable called 'num_extra_edges' that refer to the same thing, and this "extra edges" term is much better at describing these edges. So let's rename all these references to "large edges" in macro, variable, function, etc. names to "extra edges". There is a GRAPH_OCTOPUS_EDGES_NEEDED macro as well; for the sake of consistency rename it to GRAPH_EXTRA_EDGES_NEEDED. We can do so safely without causing any incompatibility issues, because the term "large edges" doesn't come up in the file format itself in any form (the chunk's magic is {'E', 'D', 'G', 'E'}, there is no 'L' in there), but only in the specification text. The string "large edges", however, does come up in the output of 'git commit-graph read' and in tests looking at its input, but that command is explicitly documented as debugging aid, so we can change its output and the affected tests safely. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-19 20:21:13 +00:00
if (!(edge_value & GRAPH_EXTRA_EDGES_NEEDED)) {
pptr = insert_parent_or_die(r, g, edge_value, pptr);
return 1;
}
commit-graph: rename "large edges" to "extra edges" The optional 'Large Edge List' chunk of the commit graph file stores parent information for commits with more than two parents, and the names of most of the macros, variables, struct fields, and functions related to this chunk contain the term "large edges", e.g. write_graph_chunk_large_edges(). However, it's not a really great term, as the edges to the second and subsequent parents stored in this chunk are not any larger than the edges to the first and second parents stored in the "main" 'Commit Data' chunk. It's the number of edges, IOW number of parents, that is larger compared to non-merge and "regular" two-parent merge commits. And indeed, two functions in 'commit-graph.c' have a local variable called 'num_extra_edges' that refer to the same thing, and this "extra edges" term is much better at describing these edges. So let's rename all these references to "large edges" in macro, variable, function, etc. names to "extra edges". There is a GRAPH_OCTOPUS_EDGES_NEEDED macro as well; for the sake of consistency rename it to GRAPH_EXTRA_EDGES_NEEDED. We can do so safely without causing any incompatibility issues, because the term "large edges" doesn't come up in the file format itself in any form (the chunk's magic is {'E', 'D', 'G', 'E'}, there is no 'L' in there), but only in the specification text. The string "large edges", however, does come up in the output of 'git commit-graph read' and in tests looking at its input, but that command is explicitly documented as debugging aid, so we can change its output and the affected tests safely. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-19 20:21:13 +00:00
parent_data_ptr = (uint32_t*)(g->chunk_extra_edges +
4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
do {
edge_value = get_be32(parent_data_ptr);
pptr = insert_parent_or_die(r, g,
edge_value & GRAPH_EDGE_LAST_MASK,
pptr);
parent_data_ptr++;
} while (!(edge_value & GRAPH_LAST_EDGE));
return 1;
}
static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
{
uint32_t graph_pos = commit_graph_position(item);
if (graph_pos != COMMIT_NOT_FROM_GRAPH) {
*pos = graph_pos;
return 1;
} else {
struct commit_graph *cur_g = g;
uint32_t lex_index;
while (cur_g && !bsearch_graph(cur_g, &(item->object.oid), &lex_index))
cur_g = cur_g->base_graph;
if (cur_g) {
*pos = lex_index + cur_g->num_commits_in_base;
return 1;
}
return 0;
}
}
static int parse_commit_in_graph_one(struct repository *r,
struct commit_graph *g,
struct commit *item)
{
uint32_t pos;
if (item->object.parsed)
return 1;
if (find_commit_in_graph(item, g, &pos))
return fill_commit_in_graph(r, item, g, pos);
return 0;
}
int parse_commit_in_graph(struct repository *r, struct commit *item)
{
static int checked_env = 0;
if (!checked_env &&
git_env_bool(GIT_TEST_COMMIT_GRAPH_DIE_ON_PARSE, 0))
die("dying as requested by the '%s' variable on commit-graph parse!",
GIT_TEST_COMMIT_GRAPH_DIE_ON_PARSE);
checked_env = 1;
if (!prepare_commit_graph(r))
return 0;
return parse_commit_in_graph_one(r, r->objects->commit_graph, item);
}
void load_commit_graph_info(struct repository *r, struct commit *item)
{
uint32_t pos;
if (!prepare_commit_graph(r))
return;
if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
fill_commit_graph_info(item, r->objects->commit_graph, pos);
}
static struct tree *load_tree_for_commit(struct repository *r,
struct commit_graph *g,
struct commit *c)
{
struct object_id oid;
const unsigned char *commit_data;
uint32_t graph_pos = commit_graph_position(c);
while (graph_pos < g->num_commits_in_base)
g = g->base_graph;
commit_data = g->chunk_commit_data +
GRAPH_DATA_WIDTH * (graph_pos - g->num_commits_in_base);
hashcpy(oid.hash, commit_data);
set_commit_tree(c, lookup_tree(r, &oid));
return c->maybe_tree;
}
static struct tree *get_commit_tree_in_graph_one(struct repository *r,
struct commit_graph *g,
const struct commit *c)
{
if (c->maybe_tree)
return c->maybe_tree;
if (commit_graph_position(c) == COMMIT_NOT_FROM_GRAPH)
BUG("get_commit_tree_in_graph_one called from non-commit-graph commit");
return load_tree_for_commit(r, g, (struct commit *)c);
}
struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
{
return get_commit_tree_in_graph_one(r, r->objects->commit_graph, c);
}
struct packed_commit_list {
struct commit **list;
int nr;
int alloc;
};
struct packed_oid_list {
struct object_id *list;
int nr;
int alloc;
};
struct write_commit_graph_context {
struct repository *r;
commit-graph.h: store an odb in 'struct write_commit_graph_context' There are lots of places in 'commit-graph.h' where a function either has (or almost has) a full 'struct object_directory *', accesses '->path', and then throws away the rest of the struct. This can cause headaches when comparing the locations of object directories across alternates (e.g., in the case of deciding if two commit-graph layers can be merged). These paths are normalized with 'normalize_path_copy()' which mitigates some comparison issues, but not all [1]. Replace usage of 'char *object_dir' with 'odb->path' by storing a 'struct object_directory *' in the 'write_commit_graph_context' structure. This is an intermediate step towards getting rid of all path normalization in 'commit-graph.c'. Resolving a user-provided '--object-dir' argument now requires that we compare it to the known alternates for equality. Prior to this patch, an unknown '--object-dir' argument would silently exit with status zero. This can clearly lead to unintended behavior, such as verifying commit-graphs that aren't in a repository's own object store (or one of its alternates), or causing a typo to mask a legitimate commit-graph verification failure. Make this error non-silent by 'die()'-ing when the given '--object-dir' does not match any known alternate object store. [1]: In my testing, for example, I can get one side of the commit-graph code to fill object_dir with "./objects" and the other with just "objects". Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-04 05:51:50 +00:00
struct object_directory *odb;
char *graph_name;
struct packed_oid_list oids;
struct packed_commit_list commits;
int num_extra_edges;
unsigned long approx_nr_objects;
struct progress *progress;
int progress_done;
uint64_t progress_cnt;
char *base_graph_name;
int num_commit_graphs_before;
int num_commit_graphs_after;
char **commit_graph_filenames_before;
char **commit_graph_filenames_after;
char **commit_graph_hash_after;
uint32_t new_num_commits_in_base;
struct commit_graph *new_base_graph;
unsigned append:1,
report_progress:1,
commit-graph: error out on invalid commit oids in 'write --stdin-commits' While 'git commit-graph write --stdin-commits' expects commit object ids as input, it accepts and silently skips over any invalid commit object ids, and still exits with success: # nonsense $ echo not-a-commit-oid | git commit-graph write --stdin-commits $ echo $? 0 # sometimes I forgot that refs are not good... $ echo HEAD | git commit-graph write --stdin-commits $ echo $? 0 # valid tree OID, but not a commit OID $ git rev-parse HEAD^{tree} | git commit-graph write --stdin-commits $ echo $? 0 $ ls -l .git/objects/info/commit-graph ls: cannot access '.git/objects/info/commit-graph': No such file or directory Check that all input records are indeed valid commit object ids and return with error otherwise, the same way '--stdin-packs' handles invalid input; see e103f7276f (commit-graph: return with errors during write, 2019-06-12). Note that it should only return with error when encountering an invalid commit object id coming from standard input. However, '--reachable' uses the same code path to process object ids pointed to by all refs, and that includes tag object ids as well, which should still be skipped over. Therefore add a new flag to 'enum commit_graph_write_flags' and a corresponding field to 'struct write_commit_graph_context', so we can differentiate between those two cases. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Acked-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-05 08:02:40 +00:00
split:1,
changed_paths:1,
order_by_pack:1;
const struct commit_graph_opts *opts;
size_t total_bloom_filter_data_size;
const struct bloom_filter_settings *bloom_settings;
int count_bloom_filter_computed;
int count_bloom_filter_not_computed;
bloom: encode out-of-bounds filters as non-empty When a changed-path Bloom filter has either zero, or more than a certain number (commonly 512) of entries, the commit-graph machinery encodes it as "missing". More specifically, it sets the indices adjacent in the BIDX chunk as equal to each other to indicate a "length 0" filter; that is, that the filter occupies zero bytes on disk. This has heretofore been fine, since the commit-graph machinery has no need to care about these filters with too few or too many changed paths. Both cases act like no filter has been generated at all, and so there is no need to store them. In a subsequent commit, however, the commit-graph machinery will learn to only compute Bloom filters for some commits in the current commit-graph layer. This is a change from the current implementation which computes Bloom filters for all commits that are in the layer being written. Critically for this patch, only computing some of the Bloom filters means adding a third state for length 0 Bloom filters: zero entries, too many entries, or "hasn't been computed". It will be important for that future patch to distinguish between "not representable" (i.e., zero or too-many changed paths), and "hasn't been computed". In particular, we don't want to waste time recomputing filters that have already been computed. To that end, change how we store Bloom filters in the "computed but not representable" category: - Bloom filters with no entries are stored as a single byte with all bits low (i.e., all queries to that Bloom filter will return "definitely not") - Bloom filters with too many entries are stored as a single byte with all bits set high (i.e., all queries to that Bloom filter will return "maybe"). These rules are sufficient to not incur a behavior change by changing the on-disk representation of these two classes. Likewise, no specification changes are necessary for the commit-graph format, either: - Filters that were previously empty will be recomputed and stored according to the new rules, and - old clients reading filters generated by new clients will interpret the filters correctly and be none the wiser to how they were generated. Clients will invoke the Bloom machinery in more cases than before, but this can be addressed by returning a NULL filter when all bits are set high. This can be addressed in a future patch. Note that this does increase the size of on-disk commit-graphs, but far less than other proposals. In particular, this is generally more efficient than storing a bitmap for which commits haven't computed their Bloom filters. Storing a bitmap incurs a penalty of one bit per commit, whereas storing explicit filters as above incurs a penalty of one byte per too-large or empty commit. In practice, these boundary commits likely occupy a small proportion of the overall number of commits, and so the size penalty is likely smaller than storing a bitmap for all commits. See, for example, these relative proportions of such boundary commits (collected by SZEDER Gábor): | Percentage of | commit-graph | | | commits modifying | file size | | ├────────┬──────────────┼───────────────────┤ pct. | | 0 path | >= 512 paths | before | after | change | ┌────────────────┼────────┼──────────────┼─────────┼─────────┼───────────┤ | android-base | 13.20% | 0.13% | 37.468M | 37.534M | +0.1741 % | | cmssw | 0.15% | 0.23% | 17.118M | 17.119M | +0.0091 % | | cpython | 3.07% | 0.01% | 7.967M | 7.971M | +0.0423 % | | elasticsearch | 0.70% | 1.00% | 8.833M | 8.835M | +0.0128 % | | gcc | 0.00% | 0.08% | 16.073M | 16.074M | +0.0030 % | | gecko-dev | 0.14% | 0.64% | 59.868M | 59.874M | +0.0105 % | | git | 0.11% | 0.02% | 3.895M | 3.895M | +0.0020 % | | glibc | 0.02% | 0.10% | 3.555M | 3.555M | +0.0021 % | | go | 0.00% | 0.07% | 3.186M | 3.186M | +0.0018 % | | homebrew-cask | 0.40% | 0.02% | 7.035M | 7.035M | +0.0065 % | | homebrew-core | 0.01% | 0.01% | 11.611M | 11.611M | +0.0002 % | | jdk | 0.26% | 5.64% | 5.537M | 5.540M | +0.0590 % | | linux | 0.01% | 0.51% | 63.735M | 63.740M | +0.0073 % | | llvm-project | 0.12% | 0.03% | 25.515M | 25.516M | +0.0050 % | | rails | 0.10% | 0.10% | 6.252M | 6.252M | +0.0027 % | | rust | 0.07% | 0.17% | 9.364M | 9.364M | +0.0033 % | | tensorflow | 0.09% | 1.02% | 7.009M | 7.010M | +0.0158 % | | webkit | 0.05% | 0.31% | 17.405M | 17.406M | +0.0047 % | (where the above increase is determined by computing a non-split commit-graph before and after this patch). Given that these projects are all "large" by commit count, the storage cost by writing these filters explicitly is negligible. In the most extreme example, android-base (which has 494,848 commits at the time of writing) would have its commit-graph increase by a modest 68.4 KB. Finally, a test to exercise filters which contain too many changed path entries will be introduced in a subsequent patch. Suggested-by: SZEDER Gábor <szeder.dev@gmail.com> Suggested-by: Jakub Narębski <jnareb@gmail.com> Helped-by: Derrick Stolee <dstolee@microsoft.com> Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-18 02:59:44 +00:00
int count_bloom_filter_trunc_empty;
int count_bloom_filter_trunc_large;
};
static int write_graph_chunk_fanout(struct hashfile *f,
struct write_commit_graph_context *ctx)
{
int i, count = 0;
struct commit **list = ctx->commits.list;
/*
* Write the first-level table (the list is sorted,
* but we use a 256-entry lookup to be able to avoid
* having to do eight extra binary search iterations).
*/
for (i = 0; i < 256; i++) {
while (count < ctx->commits.nr) {
if ((*list)->object.oid.hash[0] != i)
break;
display_progress(ctx->progress, ++ctx->progress_cnt);
count++;
list++;
}
hashwrite_be32(f, count);
}
return 0;
}
static int write_graph_chunk_oids(struct hashfile *f,
struct write_commit_graph_context *ctx)
{
struct commit **list = ctx->commits.list;
int count;
for (count = 0; count < ctx->commits.nr; count++, list++) {
display_progress(ctx->progress, ++ctx->progress_cnt);
hashwrite(f, (*list)->object.oid.hash, the_hash_algo->rawsz);
}
return 0;
}
static const unsigned char *commit_to_sha1(size_t index, void *table)
{
struct commit **commits = table;
return commits[index]->object.oid.hash;
}
static int write_graph_chunk_data(struct hashfile *f,
struct write_commit_graph_context *ctx)
{
struct commit **list = ctx->commits.list;
struct commit **last = ctx->commits.list + ctx->commits.nr;
uint32_t num_extra_edges = 0;
while (list < last) {
struct commit_list *parent;
struct object_id *tree;
int edge_value;
uint32_t packedDate[2];
display_progress(ctx->progress, ++ctx->progress_cnt);
2019-09-05 22:04:55 +00:00
if (parse_commit_no_graph(*list))
die(_("unable to parse commit %s"),
oid_to_hex(&(*list)->object.oid));
tree = get_commit_tree_oid(*list);
hashwrite(f, tree->hash, the_hash_algo->rawsz);
parent = (*list)->parents;
if (!parent)
edge_value = GRAPH_PARENT_NONE;
else {
edge_value = sha1_pos(parent->item->object.oid.hash,
ctx->commits.list,
ctx->commits.nr,
commit_to_sha1);
if (edge_value >= 0)
edge_value += ctx->new_num_commits_in_base;
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
else if (ctx->new_base_graph) {
uint32_t pos;
if (find_commit_in_graph(parent->item,
ctx->new_base_graph,
&pos))
edge_value = pos;
}
if (edge_value < 0)
BUG("missing parent %s for commit %s",
oid_to_hex(&parent->item->object.oid),
oid_to_hex(&(*list)->object.oid));
}
hashwrite_be32(f, edge_value);
if (parent)
parent = parent->next;
if (!parent)
edge_value = GRAPH_PARENT_NONE;
else if (parent->next)
commit-graph: rename "large edges" to "extra edges" The optional 'Large Edge List' chunk of the commit graph file stores parent information for commits with more than two parents, and the names of most of the macros, variables, struct fields, and functions related to this chunk contain the term "large edges", e.g. write_graph_chunk_large_edges(). However, it's not a really great term, as the edges to the second and subsequent parents stored in this chunk are not any larger than the edges to the first and second parents stored in the "main" 'Commit Data' chunk. It's the number of edges, IOW number of parents, that is larger compared to non-merge and "regular" two-parent merge commits. And indeed, two functions in 'commit-graph.c' have a local variable called 'num_extra_edges' that refer to the same thing, and this "extra edges" term is much better at describing these edges. So let's rename all these references to "large edges" in macro, variable, function, etc. names to "extra edges". There is a GRAPH_OCTOPUS_EDGES_NEEDED macro as well; for the sake of consistency rename it to GRAPH_EXTRA_EDGES_NEEDED. We can do so safely without causing any incompatibility issues, because the term "large edges" doesn't come up in the file format itself in any form (the chunk's magic is {'E', 'D', 'G', 'E'}, there is no 'L' in there), but only in the specification text. The string "large edges", however, does come up in the output of 'git commit-graph read' and in tests looking at its input, but that command is explicitly documented as debugging aid, so we can change its output and the affected tests safely. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-19 20:21:13 +00:00
edge_value = GRAPH_EXTRA_EDGES_NEEDED | num_extra_edges;
else {
edge_value = sha1_pos(parent->item->object.oid.hash,
ctx->commits.list,
ctx->commits.nr,
commit_to_sha1);
if (edge_value >= 0)
edge_value += ctx->new_num_commits_in_base;
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
else if (ctx->new_base_graph) {
uint32_t pos;
if (find_commit_in_graph(parent->item,
ctx->new_base_graph,
&pos))
edge_value = pos;
}
if (edge_value < 0)
BUG("missing parent %s for commit %s",
oid_to_hex(&parent->item->object.oid),
oid_to_hex(&(*list)->object.oid));
}
hashwrite_be32(f, edge_value);
commit-graph: rename "large edges" to "extra edges" The optional 'Large Edge List' chunk of the commit graph file stores parent information for commits with more than two parents, and the names of most of the macros, variables, struct fields, and functions related to this chunk contain the term "large edges", e.g. write_graph_chunk_large_edges(). However, it's not a really great term, as the edges to the second and subsequent parents stored in this chunk are not any larger than the edges to the first and second parents stored in the "main" 'Commit Data' chunk. It's the number of edges, IOW number of parents, that is larger compared to non-merge and "regular" two-parent merge commits. And indeed, two functions in 'commit-graph.c' have a local variable called 'num_extra_edges' that refer to the same thing, and this "extra edges" term is much better at describing these edges. So let's rename all these references to "large edges" in macro, variable, function, etc. names to "extra edges". There is a GRAPH_OCTOPUS_EDGES_NEEDED macro as well; for the sake of consistency rename it to GRAPH_EXTRA_EDGES_NEEDED. We can do so safely without causing any incompatibility issues, because the term "large edges" doesn't come up in the file format itself in any form (the chunk's magic is {'E', 'D', 'G', 'E'}, there is no 'L' in there), but only in the specification text. The string "large edges", however, does come up in the output of 'git commit-graph read' and in tests looking at its input, but that command is explicitly documented as debugging aid, so we can change its output and the affected tests safely. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-19 20:21:13 +00:00
if (edge_value & GRAPH_EXTRA_EDGES_NEEDED) {
do {
num_extra_edges++;
parent = parent->next;
} while (parent);
}
if (sizeof((*list)->date) > 4)
packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
else
packedDate[0] = 0;
packedDate[0] |= htonl(commit_graph_data_at(*list)->generation << 2);
packedDate[1] = htonl((*list)->date);
hashwrite(f, packedDate, 8);
list++;
}
return 0;
}
static int write_graph_chunk_extra_edges(struct hashfile *f,
struct write_commit_graph_context *ctx)
{
struct commit **list = ctx->commits.list;
struct commit **last = ctx->commits.list + ctx->commits.nr;
struct commit_list *parent;
while (list < last) {
int num_parents = 0;
display_progress(ctx->progress, ++ctx->progress_cnt);
for (parent = (*list)->parents; num_parents < 3 && parent;
parent = parent->next)
num_parents++;
if (num_parents <= 2) {
list++;
continue;
}
/* Since num_parents > 2, this initializer is safe. */
for (parent = (*list)->parents->next; parent; parent = parent->next) {
int edge_value = sha1_pos(parent->item->object.oid.hash,
ctx->commits.list,
ctx->commits.nr,
commit_to_sha1);
if (edge_value >= 0)
edge_value += ctx->new_num_commits_in_base;
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
else if (ctx->new_base_graph) {
uint32_t pos;
if (find_commit_in_graph(parent->item,
ctx->new_base_graph,
&pos))
edge_value = pos;
}
if (edge_value < 0)
BUG("missing parent %s for commit %s",
oid_to_hex(&parent->item->object.oid),
oid_to_hex(&(*list)->object.oid));
else if (!parent->next)
edge_value |= GRAPH_LAST_EDGE;
hashwrite_be32(f, edge_value);
}
list++;
}
return 0;
}
static int write_graph_chunk_bloom_indexes(struct hashfile *f,
struct write_commit_graph_context *ctx)
{
struct commit **list = ctx->commits.list;
struct commit **last = ctx->commits.list + ctx->commits.nr;
uint32_t cur_pos = 0;
while (list < last) {
struct bloom_filter *filter = get_bloom_filter(ctx->r, *list);
size_t len = filter ? filter->len : 0;
cur_pos += len;
display_progress(ctx->progress, ++ctx->progress_cnt);
hashwrite_be32(f, cur_pos);
list++;
}
return 0;
}
static void trace2_bloom_filter_settings(struct write_commit_graph_context *ctx)
{
struct json_writer jw = JSON_WRITER_INIT;
jw_object_begin(&jw, 0);
jw_object_intmax(&jw, "hash_version", ctx->bloom_settings->hash_version);
jw_object_intmax(&jw, "num_hashes", ctx->bloom_settings->num_hashes);
jw_object_intmax(&jw, "bits_per_entry", ctx->bloom_settings->bits_per_entry);
jw_object_intmax(&jw, "max_changed_paths", ctx->bloom_settings->max_changed_paths);
jw_end(&jw);
trace2_data_json("bloom", ctx->r, "settings", &jw);
jw_release(&jw);
}
static int write_graph_chunk_bloom_data(struct hashfile *f,
struct write_commit_graph_context *ctx)
{
struct commit **list = ctx->commits.list;
struct commit **last = ctx->commits.list + ctx->commits.nr;
trace2_bloom_filter_settings(ctx);
hashwrite_be32(f, ctx->bloom_settings->hash_version);
hashwrite_be32(f, ctx->bloom_settings->num_hashes);
hashwrite_be32(f, ctx->bloom_settings->bits_per_entry);
while (list < last) {
struct bloom_filter *filter = get_bloom_filter(ctx->r, *list);
size_t len = filter ? filter->len : 0;
display_progress(ctx->progress, ++ctx->progress_cnt);
if (len)
hashwrite(f, filter->data, len * sizeof(unsigned char));
list++;
}
return 0;
}
static int oid_compare(const void *_a, const void *_b)
{
const struct object_id *a = (const struct object_id *)_a;
const struct object_id *b = (const struct object_id *)_b;
return oidcmp(a, b);
}
static int add_packed_commits(const struct object_id *oid,
struct packed_git *pack,
uint32_t pos,
void *data)
{
struct write_commit_graph_context *ctx = (struct write_commit_graph_context*)data;
enum object_type type;
off_t offset = nth_packed_object_offset(pack, pos);
struct object_info oi = OBJECT_INFO_INIT;
if (ctx->progress)
display_progress(ctx->progress, ++ctx->progress_done);
commit-graph write: add progress output Before this change the "commit-graph write" command didn't report any progress. On my machine this command takes more than 10 seconds to write the graph for linux.git, and around 1m30s on the 2015-04-03-1M-git.git[1] test repository (a test case for a large monorepository). Furthermore, since the gc.writeCommitGraph setting was added in d5d5d7b641 ("gc: automatically write commit-graph files", 2018-06-27), there was no indication at all from a "git gc" run that anything was different. This why one of the progress bars being added here uses start_progress() instead of start_delayed_progress(), so that it's guaranteed to be seen. E.g. on my tiny 867 commit dotfiles.git repository: $ git -c gc.writeCommitGraph=true gc Enumerating objects: 2821, done. [...] Computing commit graph generation numbers: 100% (867/867), done. On larger repositories, such as linux.git the delayed progress bar(s) will kick in, and we'll show what's going on instead of, as was previously happening, printing nothing while we write the graph: $ git -c gc.writeCommitGraph=true gc [...] Annotating commits in commit graph: 1565573, done. Computing commit graph generation numbers: 100% (782484/782484), done. Note that here we don't show "Finding commits for commit graph", this is because under "git gc" we seed the search with the commit references in the repository, and that set is too small to show any progress, but would e.g. on a smaller repo such as git.git with --stdin-commits: $ git rev-list --all | git -c gc.writeCommitGraph=true write --stdin-commits Finding commits for commit graph: 100% (162576/162576), done. Computing commit graph generation numbers: 100% (162576/162576), done. With --stdin-packs we don't show any estimation of how much is left to do. This is because we might be processing more than one pack. We could be less lazy here and show progress, either by detecting that we're only processing one pack, or by first looping over the packs to discover how many commits they have. I don't see the point in doing that work. So instead we get (on 2015-04-03-1M-git.git): $ echo pack-<HASH>.idx | git -c gc.writeCommitGraph=true --exec-path=$PWD commit-graph write --stdin-packs Finding commits for commit graph: 13064614, done. Annotating commits in commit graph: 3001341, done. Computing commit graph generation numbers: 100% (1000447/1000447), done. No GC mode uses --stdin-packs. It's what they use at Microsoft to manually compute the generation numbers for their collection of large packs which are never coalesced. The reason we need a "report_progress" variable passed down from "git gc" is so that we don't report this output when we're running in the process "git gc --auto" detaches from the terminal. Since we write the commit graph from the "git gc" process itself (as opposed to what we do with say the "git repack" phase), we'd end up writing the output to .git/gc.log and reporting it to the user next time as part of the "The last gc run reported the following[...]" error, see 329e6e8794 ("gc: save log from daemonized gc --auto and print it next time", 2015-09-19). So we must keep track of whether or not we're running in that demonized mode, and if so print no progress. See [2] and subsequent replies for a discussion of an approach not taken in compute_generation_numbers(). I.e. we're saying "Computing commit graph generation numbers", even though on an established history we're mostly skipping over all the work we did in the past. This is similar to the white lie we tell in the "Writing objects" phase (not all are objects being written). Always showing progress is considered more important than accuracy. I.e. on a repository like 2015-04-03-1M-git.git we'd hang for 6 seconds with no output on the second "git gc" if no changes were made to any objects in the interim if we'd take the approach in [2]. 1. https://github.com/avar/2015-04-03-1M-git 2. <c6960252-c095-fb2b-e0bc-b1e6bb261614@gmail.com> (https://public-inbox.org/git/c6960252-c095-fb2b-e0bc-b1e6bb261614@gmail.com/) Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17 15:33:35 +00:00
oi.typep = &type;
if (packed_object_info(ctx->r, pack, offset, &oi) < 0)
die(_("unable to get type of object %s"), oid_to_hex(oid));
if (type != OBJ_COMMIT)
return 0;
ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
oidcpy(&(ctx->oids.list[ctx->oids.nr]), oid);
ctx->oids.nr++;
set_commit_pos(ctx->r, oid);
return 0;
}
static void add_missing_parents(struct write_commit_graph_context *ctx, struct commit *commit)
{
struct commit_list *parent;
for (parent = commit->parents; parent; parent = parent->next) {
commit-graph: fix writing first commit-graph during fetch The previous commit includes a failing test for an issue around fetch.writeCommitGraph and fetching in a repo with a submodule. Here, we fix that bug and set the test to "test_expect_success". The problem arises with this set of commands when the remote repo at <url> has a submodule. Note that --recurse-submodules is not needed to demonstrate the bug. $ git clone <url> test $ cd test $ git -c fetch.writeCommitGraph=true fetch origin Computing commit graph generation numbers: 100% (12/12), done. BUG: commit-graph.c:886: missing parent <hash1> for commit <hash2> Aborted (core dumped) As an initial fix, I converted the code in builtin/fetch.c that calls write_commit_graph_reachable() to instead launch a "git commit-graph write --reachable --split" process. That code worked, but is not how we want the feature to work long-term. That test did demonstrate that the issue must be something to do with internal state of the 'git fetch' process. The write_commit_graph() method in commit-graph.c ensures the commits we plan to write are "closed under reachability" using close_reachable(). This method walks from the input commits, and uses the UNINTERESTING flag to mark which commits have already been visited. This allows the walk to take O(N) time, where N is the number of commits, instead of O(P) time, where P is the number of paths. (The number of paths can be exponential in the number of commits.) However, the UNINTERESTING flag is used in lots of places in the codebase. This flag usually means some barrier to stop a commit walk, such as in revision-walking to compare histories. It is not often cleared after the walk completes because the starting points of those walks do not have the UNINTERESTING flag, and clear_commit_marks() would stop immediately. This is happening during a 'git fetch' call with a remote. The fetch negotiation is comparing the remote refs with the local refs and marking some commits as UNINTERESTING. I tested running clear_commit_marks_many() to clear the UNINTERESTING flag inside close_reachable(), but the tips did not have the flag, so that did nothing. It turns out that the calculate_changed_submodule_paths() method is at fault. Thanks, Peff, for pointing out this detail! More specifically, for each submodule, the collect_changed_submodules() runs a revision walk to essentially do file-history on the list of submodules. That revision walk marks commits UNININTERESTING if they are simplified away by not changing the submodule. Instead, I finally arrived on the conclusion that I should use a flag that is not used in any other part of the code. In commit-reach.c, a number of flags were defined for commit walk algorithms. The REACHABLE flag seemed like it made the most sense, and it seems it was not actually used in the file. The REACHABLE flag was used in early versions of commit-reach.c, but was removed by 4fbcca4 (commit-reach: make can_all_from_reach... linear, 2018-07-20). Add the REACHABLE flag to commit-graph.c and use it instead of UNINTERESTING in close_reachable(). This fixes the bug in manual testing. Reported-by: Johannes Schindelin <johannes.schindelin@gmx.de> Helped-by: Jeff King <peff@peff.net> Helped-by: Szeder Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-24 13:40:42 +00:00
if (!(parent->item->object.flags & REACHABLE)) {
ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
oidcpy(&ctx->oids.list[ctx->oids.nr], &(parent->item->object.oid));
ctx->oids.nr++;
commit-graph: fix writing first commit-graph during fetch The previous commit includes a failing test for an issue around fetch.writeCommitGraph and fetching in a repo with a submodule. Here, we fix that bug and set the test to "test_expect_success". The problem arises with this set of commands when the remote repo at <url> has a submodule. Note that --recurse-submodules is not needed to demonstrate the bug. $ git clone <url> test $ cd test $ git -c fetch.writeCommitGraph=true fetch origin Computing commit graph generation numbers: 100% (12/12), done. BUG: commit-graph.c:886: missing parent <hash1> for commit <hash2> Aborted (core dumped) As an initial fix, I converted the code in builtin/fetch.c that calls write_commit_graph_reachable() to instead launch a "git commit-graph write --reachable --split" process. That code worked, but is not how we want the feature to work long-term. That test did demonstrate that the issue must be something to do with internal state of the 'git fetch' process. The write_commit_graph() method in commit-graph.c ensures the commits we plan to write are "closed under reachability" using close_reachable(). This method walks from the input commits, and uses the UNINTERESTING flag to mark which commits have already been visited. This allows the walk to take O(N) time, where N is the number of commits, instead of O(P) time, where P is the number of paths. (The number of paths can be exponential in the number of commits.) However, the UNINTERESTING flag is used in lots of places in the codebase. This flag usually means some barrier to stop a commit walk, such as in revision-walking to compare histories. It is not often cleared after the walk completes because the starting points of those walks do not have the UNINTERESTING flag, and clear_commit_marks() would stop immediately. This is happening during a 'git fetch' call with a remote. The fetch negotiation is comparing the remote refs with the local refs and marking some commits as UNINTERESTING. I tested running clear_commit_marks_many() to clear the UNINTERESTING flag inside close_reachable(), but the tips did not have the flag, so that did nothing. It turns out that the calculate_changed_submodule_paths() method is at fault. Thanks, Peff, for pointing out this detail! More specifically, for each submodule, the collect_changed_submodules() runs a revision walk to essentially do file-history on the list of submodules. That revision walk marks commits UNININTERESTING if they are simplified away by not changing the submodule. Instead, I finally arrived on the conclusion that I should use a flag that is not used in any other part of the code. In commit-reach.c, a number of flags were defined for commit walk algorithms. The REACHABLE flag seemed like it made the most sense, and it seems it was not actually used in the file. The REACHABLE flag was used in early versions of commit-reach.c, but was removed by 4fbcca4 (commit-reach: make can_all_from_reach... linear, 2018-07-20). Add the REACHABLE flag to commit-graph.c and use it instead of UNINTERESTING in close_reachable(). This fixes the bug in manual testing. Reported-by: Johannes Schindelin <johannes.schindelin@gmx.de> Helped-by: Jeff King <peff@peff.net> Helped-by: Szeder Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-24 13:40:42 +00:00
parent->item->object.flags |= REACHABLE;
}
}
}
static void close_reachable(struct write_commit_graph_context *ctx)
{
int i;
struct commit *commit;
enum commit_graph_split_flags flags = ctx->opts ?
ctx->opts->split_flags : COMMIT_GRAPH_SPLIT_UNSPECIFIED;
if (ctx->report_progress)
ctx->progress = start_delayed_progress(
_("Loading known commits in commit graph"),
ctx->oids.nr);
for (i = 0; i < ctx->oids.nr; i++) {
display_progress(ctx->progress, i + 1);
commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
if (commit)
commit-graph: fix writing first commit-graph during fetch The previous commit includes a failing test for an issue around fetch.writeCommitGraph and fetching in a repo with a submodule. Here, we fix that bug and set the test to "test_expect_success". The problem arises with this set of commands when the remote repo at <url> has a submodule. Note that --recurse-submodules is not needed to demonstrate the bug. $ git clone <url> test $ cd test $ git -c fetch.writeCommitGraph=true fetch origin Computing commit graph generation numbers: 100% (12/12), done. BUG: commit-graph.c:886: missing parent <hash1> for commit <hash2> Aborted (core dumped) As an initial fix, I converted the code in builtin/fetch.c that calls write_commit_graph_reachable() to instead launch a "git commit-graph write --reachable --split" process. That code worked, but is not how we want the feature to work long-term. That test did demonstrate that the issue must be something to do with internal state of the 'git fetch' process. The write_commit_graph() method in commit-graph.c ensures the commits we plan to write are "closed under reachability" using close_reachable(). This method walks from the input commits, and uses the UNINTERESTING flag to mark which commits have already been visited. This allows the walk to take O(N) time, where N is the number of commits, instead of O(P) time, where P is the number of paths. (The number of paths can be exponential in the number of commits.) However, the UNINTERESTING flag is used in lots of places in the codebase. This flag usually means some barrier to stop a commit walk, such as in revision-walking to compare histories. It is not often cleared after the walk completes because the starting points of those walks do not have the UNINTERESTING flag, and clear_commit_marks() would stop immediately. This is happening during a 'git fetch' call with a remote. The fetch negotiation is comparing the remote refs with the local refs and marking some commits as UNINTERESTING. I tested running clear_commit_marks_many() to clear the UNINTERESTING flag inside close_reachable(), but the tips did not have the flag, so that did nothing. It turns out that the calculate_changed_submodule_paths() method is at fault. Thanks, Peff, for pointing out this detail! More specifically, for each submodule, the collect_changed_submodules() runs a revision walk to essentially do file-history on the list of submodules. That revision walk marks commits UNININTERESTING if they are simplified away by not changing the submodule. Instead, I finally arrived on the conclusion that I should use a flag that is not used in any other part of the code. In commit-reach.c, a number of flags were defined for commit walk algorithms. The REACHABLE flag seemed like it made the most sense, and it seems it was not actually used in the file. The REACHABLE flag was used in early versions of commit-reach.c, but was removed by 4fbcca4 (commit-reach: make can_all_from_reach... linear, 2018-07-20). Add the REACHABLE flag to commit-graph.c and use it instead of UNINTERESTING in close_reachable(). This fixes the bug in manual testing. Reported-by: Johannes Schindelin <johannes.schindelin@gmx.de> Helped-by: Jeff King <peff@peff.net> Helped-by: Szeder Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-24 13:40:42 +00:00
commit->object.flags |= REACHABLE;
}
stop_progress(&ctx->progress);
/*
* As this loop runs, ctx->oids.nr may grow, but not more
* than the number of missing commits in the reachable
* closure.
*/
if (ctx->report_progress)
ctx->progress = start_delayed_progress(
_("Expanding reachable commits in commit graph"),
commit-graph: don't show progress percentages while expanding reachable commits Commit 49bbc57a57 (commit-graph write: emit a percentage for all progress, 2019-01-19) was a bit overeager when it added progress percentages to the "Expanding reachable commits in commit graph" phase as well, because most of the time the number of commits that phase has to iterate over is not known in advance and grows significantly, and, consequently, we end up with nonsensical numbers: $ git commit-graph write --reachable Expanding reachable commits in commit graph: 138606% (824706/595), done. [...] $ git rev-parse v5.0 | git commit-graph write --stdin-commits Expanding reachable commits in commit graph: 81264400% (812644/1), done. [...] Even worse, because the percentage grows so quickly, the progress code outputs much more often than it should (because it ticks every second, or every 1%), slowing the whole process down. My time for "git commit-graph write --reachable" on linux.git went from 13.463s to 12.521s with this patch, ~7% savings. Therefore, don't show progress percentages in the "Expanding reachable commits in commit graph" phase. Note that the current code does sometimes do the right thing, if we picked up all commits initially (e.g., omitting "--reachable" in a fully-packed repository would get the correct count without any parent traversal). So it may be possible to come up with a way to tell when we could use a percentage here. But in the meantime, let's make sure we robustly avoid printing nonsense. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-09-07 05:01:33 +00:00
0);
for (i = 0; i < ctx->oids.nr; i++) {
display_progress(ctx->progress, i + 1);
commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
if (!commit)
continue;
if (ctx->split) {
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
if ((!parse_commit(commit) &&
commit_graph_position(commit) == COMMIT_NOT_FROM_GRAPH) ||
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
flags == COMMIT_GRAPH_SPLIT_REPLACE)
add_missing_parents(ctx, commit);
} else if (!parse_commit_no_graph(commit))
add_missing_parents(ctx, commit);
}
stop_progress(&ctx->progress);
if (ctx->report_progress)
ctx->progress = start_delayed_progress(
_("Clearing commit marks in commit graph"),
ctx->oids.nr);
for (i = 0; i < ctx->oids.nr; i++) {
display_progress(ctx->progress, i + 1);
commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
if (commit)
commit-graph: fix writing first commit-graph during fetch The previous commit includes a failing test for an issue around fetch.writeCommitGraph and fetching in a repo with a submodule. Here, we fix that bug and set the test to "test_expect_success". The problem arises with this set of commands when the remote repo at <url> has a submodule. Note that --recurse-submodules is not needed to demonstrate the bug. $ git clone <url> test $ cd test $ git -c fetch.writeCommitGraph=true fetch origin Computing commit graph generation numbers: 100% (12/12), done. BUG: commit-graph.c:886: missing parent <hash1> for commit <hash2> Aborted (core dumped) As an initial fix, I converted the code in builtin/fetch.c that calls write_commit_graph_reachable() to instead launch a "git commit-graph write --reachable --split" process. That code worked, but is not how we want the feature to work long-term. That test did demonstrate that the issue must be something to do with internal state of the 'git fetch' process. The write_commit_graph() method in commit-graph.c ensures the commits we plan to write are "closed under reachability" using close_reachable(). This method walks from the input commits, and uses the UNINTERESTING flag to mark which commits have already been visited. This allows the walk to take O(N) time, where N is the number of commits, instead of O(P) time, where P is the number of paths. (The number of paths can be exponential in the number of commits.) However, the UNINTERESTING flag is used in lots of places in the codebase. This flag usually means some barrier to stop a commit walk, such as in revision-walking to compare histories. It is not often cleared after the walk completes because the starting points of those walks do not have the UNINTERESTING flag, and clear_commit_marks() would stop immediately. This is happening during a 'git fetch' call with a remote. The fetch negotiation is comparing the remote refs with the local refs and marking some commits as UNINTERESTING. I tested running clear_commit_marks_many() to clear the UNINTERESTING flag inside close_reachable(), but the tips did not have the flag, so that did nothing. It turns out that the calculate_changed_submodule_paths() method is at fault. Thanks, Peff, for pointing out this detail! More specifically, for each submodule, the collect_changed_submodules() runs a revision walk to essentially do file-history on the list of submodules. That revision walk marks commits UNININTERESTING if they are simplified away by not changing the submodule. Instead, I finally arrived on the conclusion that I should use a flag that is not used in any other part of the code. In commit-reach.c, a number of flags were defined for commit walk algorithms. The REACHABLE flag seemed like it made the most sense, and it seems it was not actually used in the file. The REACHABLE flag was used in early versions of commit-reach.c, but was removed by 4fbcca4 (commit-reach: make can_all_from_reach... linear, 2018-07-20). Add the REACHABLE flag to commit-graph.c and use it instead of UNINTERESTING in close_reachable(). This fixes the bug in manual testing. Reported-by: Johannes Schindelin <johannes.schindelin@gmx.de> Helped-by: Jeff King <peff@peff.net> Helped-by: Szeder Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-24 13:40:42 +00:00
commit->object.flags &= ~REACHABLE;
}
stop_progress(&ctx->progress);
}
static void compute_generation_numbers(struct write_commit_graph_context *ctx)
{
int i;
struct commit_list *list = NULL;
if (ctx->report_progress)
ctx->progress = start_delayed_progress(
_("Computing commit graph generation numbers"),
ctx->commits.nr);
for (i = 0; i < ctx->commits.nr; i++) {
uint32_t generation = commit_graph_data_at(ctx->commits.list[i])->generation;
display_progress(ctx->progress, i + 1);
if (generation != GENERATION_NUMBER_INFINITY &&
generation != GENERATION_NUMBER_ZERO)
continue;
commit_list_insert(ctx->commits.list[i], &list);
while (list) {
struct commit *current = list->item;
struct commit_list *parent;
int all_parents_computed = 1;
uint32_t max_generation = 0;
for (parent = current->parents; parent; parent = parent->next) {
generation = commit_graph_data_at(parent->item)->generation;
if (generation == GENERATION_NUMBER_INFINITY ||
generation == GENERATION_NUMBER_ZERO) {
all_parents_computed = 0;
commit_list_insert(parent->item, &list);
break;
} else if (generation > max_generation) {
max_generation = generation;
}
}
if (all_parents_computed) {
struct commit_graph_data *data = commit_graph_data_at(current);
data->generation = max_generation + 1;
pop_commit(&list);
if (data->generation > GENERATION_NUMBER_MAX)
data->generation = GENERATION_NUMBER_MAX;
}
}
}
stop_progress(&ctx->progress);
}
static void trace2_bloom_filter_write_statistics(struct write_commit_graph_context *ctx)
{
trace2_data_intmax("commit-graph", ctx->r, "filter-computed",
ctx->count_bloom_filter_computed);
trace2_data_intmax("commit-graph", ctx->r, "filter-not-computed",
ctx->count_bloom_filter_not_computed);
bloom: encode out-of-bounds filters as non-empty When a changed-path Bloom filter has either zero, or more than a certain number (commonly 512) of entries, the commit-graph machinery encodes it as "missing". More specifically, it sets the indices adjacent in the BIDX chunk as equal to each other to indicate a "length 0" filter; that is, that the filter occupies zero bytes on disk. This has heretofore been fine, since the commit-graph machinery has no need to care about these filters with too few or too many changed paths. Both cases act like no filter has been generated at all, and so there is no need to store them. In a subsequent commit, however, the commit-graph machinery will learn to only compute Bloom filters for some commits in the current commit-graph layer. This is a change from the current implementation which computes Bloom filters for all commits that are in the layer being written. Critically for this patch, only computing some of the Bloom filters means adding a third state for length 0 Bloom filters: zero entries, too many entries, or "hasn't been computed". It will be important for that future patch to distinguish between "not representable" (i.e., zero or too-many changed paths), and "hasn't been computed". In particular, we don't want to waste time recomputing filters that have already been computed. To that end, change how we store Bloom filters in the "computed but not representable" category: - Bloom filters with no entries are stored as a single byte with all bits low (i.e., all queries to that Bloom filter will return "definitely not") - Bloom filters with too many entries are stored as a single byte with all bits set high (i.e., all queries to that Bloom filter will return "maybe"). These rules are sufficient to not incur a behavior change by changing the on-disk representation of these two classes. Likewise, no specification changes are necessary for the commit-graph format, either: - Filters that were previously empty will be recomputed and stored according to the new rules, and - old clients reading filters generated by new clients will interpret the filters correctly and be none the wiser to how they were generated. Clients will invoke the Bloom machinery in more cases than before, but this can be addressed by returning a NULL filter when all bits are set high. This can be addressed in a future patch. Note that this does increase the size of on-disk commit-graphs, but far less than other proposals. In particular, this is generally more efficient than storing a bitmap for which commits haven't computed their Bloom filters. Storing a bitmap incurs a penalty of one bit per commit, whereas storing explicit filters as above incurs a penalty of one byte per too-large or empty commit. In practice, these boundary commits likely occupy a small proportion of the overall number of commits, and so the size penalty is likely smaller than storing a bitmap for all commits. See, for example, these relative proportions of such boundary commits (collected by SZEDER Gábor): | Percentage of | commit-graph | | | commits modifying | file size | | ├────────┬──────────────┼───────────────────┤ pct. | | 0 path | >= 512 paths | before | after | change | ┌────────────────┼────────┼──────────────┼─────────┼─────────┼───────────┤ | android-base | 13.20% | 0.13% | 37.468M | 37.534M | +0.1741 % | | cmssw | 0.15% | 0.23% | 17.118M | 17.119M | +0.0091 % | | cpython | 3.07% | 0.01% | 7.967M | 7.971M | +0.0423 % | | elasticsearch | 0.70% | 1.00% | 8.833M | 8.835M | +0.0128 % | | gcc | 0.00% | 0.08% | 16.073M | 16.074M | +0.0030 % | | gecko-dev | 0.14% | 0.64% | 59.868M | 59.874M | +0.0105 % | | git | 0.11% | 0.02% | 3.895M | 3.895M | +0.0020 % | | glibc | 0.02% | 0.10% | 3.555M | 3.555M | +0.0021 % | | go | 0.00% | 0.07% | 3.186M | 3.186M | +0.0018 % | | homebrew-cask | 0.40% | 0.02% | 7.035M | 7.035M | +0.0065 % | | homebrew-core | 0.01% | 0.01% | 11.611M | 11.611M | +0.0002 % | | jdk | 0.26% | 5.64% | 5.537M | 5.540M | +0.0590 % | | linux | 0.01% | 0.51% | 63.735M | 63.740M | +0.0073 % | | llvm-project | 0.12% | 0.03% | 25.515M | 25.516M | +0.0050 % | | rails | 0.10% | 0.10% | 6.252M | 6.252M | +0.0027 % | | rust | 0.07% | 0.17% | 9.364M | 9.364M | +0.0033 % | | tensorflow | 0.09% | 1.02% | 7.009M | 7.010M | +0.0158 % | | webkit | 0.05% | 0.31% | 17.405M | 17.406M | +0.0047 % | (where the above increase is determined by computing a non-split commit-graph before and after this patch). Given that these projects are all "large" by commit count, the storage cost by writing these filters explicitly is negligible. In the most extreme example, android-base (which has 494,848 commits at the time of writing) would have its commit-graph increase by a modest 68.4 KB. Finally, a test to exercise filters which contain too many changed path entries will be introduced in a subsequent patch. Suggested-by: SZEDER Gábor <szeder.dev@gmail.com> Suggested-by: Jakub Narębski <jnareb@gmail.com> Helped-by: Derrick Stolee <dstolee@microsoft.com> Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-18 02:59:44 +00:00
trace2_data_intmax("commit-graph", ctx->r, "filter-trunc-empty",
ctx->count_bloom_filter_trunc_empty);
trace2_data_intmax("commit-graph", ctx->r, "filter-trunc-large",
ctx->count_bloom_filter_trunc_large);
}
static void compute_bloom_filters(struct write_commit_graph_context *ctx)
{
int i;
struct progress *progress = NULL;
struct commit **sorted_commits;
2020-09-18 13:27:27 +00:00
int max_new_filters;
init_bloom_filters();
if (ctx->report_progress)
progress = start_delayed_progress(
_("Computing commit changed paths Bloom filters"),
ctx->commits.nr);
ALLOC_ARRAY(sorted_commits, ctx->commits.nr);
COPY_ARRAY(sorted_commits, ctx->commits.list, ctx->commits.nr);
if (ctx->order_by_pack)
QSORT(sorted_commits, ctx->commits.nr, commit_pos_cmp);
else
QSORT(sorted_commits, ctx->commits.nr, commit_gen_cmp);
2020-09-18 13:27:27 +00:00
max_new_filters = ctx->opts && ctx->opts->max_new_filters >= 0 ?
ctx->opts->max_new_filters : ctx->commits.nr;
for (i = 0; i < ctx->commits.nr; i++) {
enum bloom_filter_computed computed = 0;
struct commit *c = sorted_commits[i];
struct bloom_filter *filter = get_or_compute_bloom_filter(
ctx->r,
c,
2020-09-18 13:27:27 +00:00
ctx->count_bloom_filter_computed < max_new_filters,
ctx->bloom_settings,
&computed);
if (computed & BLOOM_COMPUTED) {
ctx->count_bloom_filter_computed++;
bloom: encode out-of-bounds filters as non-empty When a changed-path Bloom filter has either zero, or more than a certain number (commonly 512) of entries, the commit-graph machinery encodes it as "missing". More specifically, it sets the indices adjacent in the BIDX chunk as equal to each other to indicate a "length 0" filter; that is, that the filter occupies zero bytes on disk. This has heretofore been fine, since the commit-graph machinery has no need to care about these filters with too few or too many changed paths. Both cases act like no filter has been generated at all, and so there is no need to store them. In a subsequent commit, however, the commit-graph machinery will learn to only compute Bloom filters for some commits in the current commit-graph layer. This is a change from the current implementation which computes Bloom filters for all commits that are in the layer being written. Critically for this patch, only computing some of the Bloom filters means adding a third state for length 0 Bloom filters: zero entries, too many entries, or "hasn't been computed". It will be important for that future patch to distinguish between "not representable" (i.e., zero or too-many changed paths), and "hasn't been computed". In particular, we don't want to waste time recomputing filters that have already been computed. To that end, change how we store Bloom filters in the "computed but not representable" category: - Bloom filters with no entries are stored as a single byte with all bits low (i.e., all queries to that Bloom filter will return "definitely not") - Bloom filters with too many entries are stored as a single byte with all bits set high (i.e., all queries to that Bloom filter will return "maybe"). These rules are sufficient to not incur a behavior change by changing the on-disk representation of these two classes. Likewise, no specification changes are necessary for the commit-graph format, either: - Filters that were previously empty will be recomputed and stored according to the new rules, and - old clients reading filters generated by new clients will interpret the filters correctly and be none the wiser to how they were generated. Clients will invoke the Bloom machinery in more cases than before, but this can be addressed by returning a NULL filter when all bits are set high. This can be addressed in a future patch. Note that this does increase the size of on-disk commit-graphs, but far less than other proposals. In particular, this is generally more efficient than storing a bitmap for which commits haven't computed their Bloom filters. Storing a bitmap incurs a penalty of one bit per commit, whereas storing explicit filters as above incurs a penalty of one byte per too-large or empty commit. In practice, these boundary commits likely occupy a small proportion of the overall number of commits, and so the size penalty is likely smaller than storing a bitmap for all commits. See, for example, these relative proportions of such boundary commits (collected by SZEDER Gábor): | Percentage of | commit-graph | | | commits modifying | file size | | ├────────┬──────────────┼───────────────────┤ pct. | | 0 path | >= 512 paths | before | after | change | ┌────────────────┼────────┼──────────────┼─────────┼─────────┼───────────┤ | android-base | 13.20% | 0.13% | 37.468M | 37.534M | +0.1741 % | | cmssw | 0.15% | 0.23% | 17.118M | 17.119M | +0.0091 % | | cpython | 3.07% | 0.01% | 7.967M | 7.971M | +0.0423 % | | elasticsearch | 0.70% | 1.00% | 8.833M | 8.835M | +0.0128 % | | gcc | 0.00% | 0.08% | 16.073M | 16.074M | +0.0030 % | | gecko-dev | 0.14% | 0.64% | 59.868M | 59.874M | +0.0105 % | | git | 0.11% | 0.02% | 3.895M | 3.895M | +0.0020 % | | glibc | 0.02% | 0.10% | 3.555M | 3.555M | +0.0021 % | | go | 0.00% | 0.07% | 3.186M | 3.186M | +0.0018 % | | homebrew-cask | 0.40% | 0.02% | 7.035M | 7.035M | +0.0065 % | | homebrew-core | 0.01% | 0.01% | 11.611M | 11.611M | +0.0002 % | | jdk | 0.26% | 5.64% | 5.537M | 5.540M | +0.0590 % | | linux | 0.01% | 0.51% | 63.735M | 63.740M | +0.0073 % | | llvm-project | 0.12% | 0.03% | 25.515M | 25.516M | +0.0050 % | | rails | 0.10% | 0.10% | 6.252M | 6.252M | +0.0027 % | | rust | 0.07% | 0.17% | 9.364M | 9.364M | +0.0033 % | | tensorflow | 0.09% | 1.02% | 7.009M | 7.010M | +0.0158 % | | webkit | 0.05% | 0.31% | 17.405M | 17.406M | +0.0047 % | (where the above increase is determined by computing a non-split commit-graph before and after this patch). Given that these projects are all "large" by commit count, the storage cost by writing these filters explicitly is negligible. In the most extreme example, android-base (which has 494,848 commits at the time of writing) would have its commit-graph increase by a modest 68.4 KB. Finally, a test to exercise filters which contain too many changed path entries will be introduced in a subsequent patch. Suggested-by: SZEDER Gábor <szeder.dev@gmail.com> Suggested-by: Jakub Narębski <jnareb@gmail.com> Helped-by: Derrick Stolee <dstolee@microsoft.com> Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-18 02:59:44 +00:00
if (computed & BLOOM_TRUNC_EMPTY)
ctx->count_bloom_filter_trunc_empty++;
if (computed & BLOOM_TRUNC_LARGE)
ctx->count_bloom_filter_trunc_large++;
} else if (computed & BLOOM_NOT_COMPUTED)
ctx->count_bloom_filter_not_computed++;
2020-09-18 13:27:27 +00:00
ctx->total_bloom_filter_data_size += filter
? sizeof(unsigned char) * filter->len : 0;
display_progress(progress, i + 1);
}
if (trace2_is_enabled())
trace2_bloom_filter_write_statistics(ctx);
free(sorted_commits);
stop_progress(&progress);
}
struct refs_cb_data {
struct oidset *commits;
struct progress *progress;
};
static int add_ref_to_set(const char *refname,
const struct object_id *oid,
int flags, void *cb_data)
{
struct object_id peeled;
struct refs_cb_data *data = (struct refs_cb_data *)cb_data;
if (!peel_ref(refname, &peeled))
oid = &peeled;
if (oid_object_info(the_repository, oid, NULL) == OBJ_COMMIT)
oidset_insert(data->commits, oid);
display_progress(data->progress, oidset_size(data->commits));
return 0;
}
commit-graph.h: store an odb in 'struct write_commit_graph_context' There are lots of places in 'commit-graph.h' where a function either has (or almost has) a full 'struct object_directory *', accesses '->path', and then throws away the rest of the struct. This can cause headaches when comparing the locations of object directories across alternates (e.g., in the case of deciding if two commit-graph layers can be merged). These paths are normalized with 'normalize_path_copy()' which mitigates some comparison issues, but not all [1]. Replace usage of 'char *object_dir' with 'odb->path' by storing a 'struct object_directory *' in the 'write_commit_graph_context' structure. This is an intermediate step towards getting rid of all path normalization in 'commit-graph.c'. Resolving a user-provided '--object-dir' argument now requires that we compare it to the known alternates for equality. Prior to this patch, an unknown '--object-dir' argument would silently exit with status zero. This can clearly lead to unintended behavior, such as verifying commit-graphs that aren't in a repository's own object store (or one of its alternates), or causing a typo to mask a legitimate commit-graph verification failure. Make this error non-silent by 'die()'-ing when the given '--object-dir' does not match any known alternate object store. [1]: In my testing, for example, I can get one side of the commit-graph code to fill object_dir with "./objects" and the other with just "objects". Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-04 05:51:50 +00:00
int write_commit_graph_reachable(struct object_directory *odb,
enum commit_graph_write_flags flags,
const struct commit_graph_opts *opts)
{
struct oidset commits = OIDSET_INIT;
struct refs_cb_data data;
int result;
memset(&data, 0, sizeof(data));
data.commits = &commits;
if (flags & COMMIT_GRAPH_WRITE_PROGRESS)
data.progress = start_delayed_progress(
_("Collecting referenced commits"), 0);
for_each_ref(add_ref_to_set, &data);
stop_progress(&data.progress);
result = write_commit_graph(odb, NULL, &commits,
flags, opts);
oidset_clear(&commits);
return result;
}
static int fill_oids_from_packs(struct write_commit_graph_context *ctx,
struct string_list *pack_indexes)
{
uint32_t i;
struct strbuf progress_title = STRBUF_INIT;
struct strbuf packname = STRBUF_INIT;
int dirlen;
commit-graph.h: store an odb in 'struct write_commit_graph_context' There are lots of places in 'commit-graph.h' where a function either has (or almost has) a full 'struct object_directory *', accesses '->path', and then throws away the rest of the struct. This can cause headaches when comparing the locations of object directories across alternates (e.g., in the case of deciding if two commit-graph layers can be merged). These paths are normalized with 'normalize_path_copy()' which mitigates some comparison issues, but not all [1]. Replace usage of 'char *object_dir' with 'odb->path' by storing a 'struct object_directory *' in the 'write_commit_graph_context' structure. This is an intermediate step towards getting rid of all path normalization in 'commit-graph.c'. Resolving a user-provided '--object-dir' argument now requires that we compare it to the known alternates for equality. Prior to this patch, an unknown '--object-dir' argument would silently exit with status zero. This can clearly lead to unintended behavior, such as verifying commit-graphs that aren't in a repository's own object store (or one of its alternates), or causing a typo to mask a legitimate commit-graph verification failure. Make this error non-silent by 'die()'-ing when the given '--object-dir' does not match any known alternate object store. [1]: In my testing, for example, I can get one side of the commit-graph code to fill object_dir with "./objects" and the other with just "objects". Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-04 05:51:50 +00:00
strbuf_addf(&packname, "%s/pack/", ctx->odb->path);
dirlen = packname.len;
if (ctx->report_progress) {
strbuf_addf(&progress_title,
Q_("Finding commits for commit graph in %d pack",
"Finding commits for commit graph in %d packs",
pack_indexes->nr),
pack_indexes->nr);
ctx->progress = start_delayed_progress(progress_title.buf, 0);
ctx->progress_done = 0;
}
for (i = 0; i < pack_indexes->nr; i++) {
struct packed_git *p;
strbuf_setlen(&packname, dirlen);
strbuf_addstr(&packname, pack_indexes->items[i].string);
p = add_packed_git(packname.buf, packname.len, 1);
if (!p) {
error(_("error adding pack %s"), packname.buf);
return -1;
}
if (open_pack_index(p)) {
error(_("error opening index for %s"), packname.buf);
return -1;
}
for_each_object_in_pack(p, add_packed_commits, ctx,
FOR_EACH_OBJECT_PACK_ORDER);
close_pack(p);
free(p);
}
stop_progress(&ctx->progress);
strbuf_release(&progress_title);
strbuf_release(&packname);
return 0;
}
static int fill_oids_from_commits(struct write_commit_graph_context *ctx,
struct oidset *commits)
{
struct oidset_iter iter;
struct object_id *oid;
if (!oidset_size(commits))
return 0;
oidset_iter_init(commits, &iter);
while ((oid = oidset_iter_next(&iter))) {
ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
oidcpy(&ctx->oids.list[ctx->oids.nr], oid);
ctx->oids.nr++;
}
commit-graph: error out on invalid commit oids in 'write --stdin-commits' While 'git commit-graph write --stdin-commits' expects commit object ids as input, it accepts and silently skips over any invalid commit object ids, and still exits with success: # nonsense $ echo not-a-commit-oid | git commit-graph write --stdin-commits $ echo $? 0 # sometimes I forgot that refs are not good... $ echo HEAD | git commit-graph write --stdin-commits $ echo $? 0 # valid tree OID, but not a commit OID $ git rev-parse HEAD^{tree} | git commit-graph write --stdin-commits $ echo $? 0 $ ls -l .git/objects/info/commit-graph ls: cannot access '.git/objects/info/commit-graph': No such file or directory Check that all input records are indeed valid commit object ids and return with error otherwise, the same way '--stdin-packs' handles invalid input; see e103f7276f (commit-graph: return with errors during write, 2019-06-12). Note that it should only return with error when encountering an invalid commit object id coming from standard input. However, '--reachable' uses the same code path to process object ids pointed to by all refs, and that includes tag object ids as well, which should still be skipped over. Therefore add a new flag to 'enum commit_graph_write_flags' and a corresponding field to 'struct write_commit_graph_context', so we can differentiate between those two cases. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Acked-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-05 08:02:40 +00:00
return 0;
}
static void fill_oids_from_all_packs(struct write_commit_graph_context *ctx)
{
if (ctx->report_progress)
ctx->progress = start_delayed_progress(
_("Finding commits for commit graph among packed objects"),
ctx->approx_nr_objects);
for_each_packed_object(add_packed_commits, ctx,
FOR_EACH_OBJECT_PACK_ORDER);
if (ctx->progress_done < ctx->approx_nr_objects)
display_progress(ctx->progress, ctx->approx_nr_objects);
stop_progress(&ctx->progress);
}
static uint32_t count_distinct_commits(struct write_commit_graph_context *ctx)
{
uint32_t i, count_distinct = 1;
if (ctx->report_progress)
ctx->progress = start_delayed_progress(
commit-graph write: add itermediate progress Add progress output to sections of code between "Annotating[...]" and "Computing[...]generation numbers". This can collectively take 5-10 seconds on a large enough repository. On a test repository with I have with ~7 million commits and ~50 million objects we'll now emit: $ ~/g/git/git --exec-path=$HOME/g/git commit-graph write Finding commits for commit graph among packed objects: 100% (124763727/124763727), done. Loading known commits in commit graph: 100% (18989461/18989461), done. Expanding reachable commits in commit graph: 100% (18989507/18989461), done. Clearing commit marks in commit graph: 100% (18989507/18989507), done. Counting distinct commits in commit graph: 100% (18989507/18989507), done. Finding extra edges in commit graph: 100% (18989507/18989507), done. Computing commit graph generation numbers: 100% (7250302/7250302), done. Writing out commit graph in 4 passes: 100% (29001208/29001208), done. Whereas on a medium-sized repository such as linux.git these new progress bars won't have time to kick in and as before and we'll still emit output like: $ ~/g/git/git --exec-path=$HOME/g/git commit-graph write Finding commits for commit graph among packed objects: 100% (6529159/6529159), done. Expanding reachable commits in commit graph: 815990, done. Computing commit graph generation numbers: 100% (815983/815983), done. Writing out commit graph in 4 passes: 100% (3263932/3263932), done. The "Counting distinct commits in commit graph" phase will spend most of its time paused at "0/*" as we QSORT(...) the list. That's not optimal, but at least we don't seem to be stalling anymore most of the time. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-19 20:21:20 +00:00
_("Counting distinct commits in commit graph"),
ctx->oids.nr);
display_progress(ctx->progress, 0); /* TODO: Measure QSORT() progress */
QSORT(ctx->oids.list, ctx->oids.nr, oid_compare);
for (i = 1; i < ctx->oids.nr; i++) {
display_progress(ctx->progress, i + 1);
if (!oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i])) {
if (ctx->split) {
struct commit *c = lookup_commit(ctx->r, &ctx->oids.list[i]);
if (!c || commit_graph_position(c) != COMMIT_NOT_FROM_GRAPH)
continue;
}
count_distinct++;
}
}
stop_progress(&ctx->progress);
return count_distinct;
}
static void copy_oids_to_commits(struct write_commit_graph_context *ctx)
{
uint32_t i;
enum commit_graph_split_flags flags = ctx->opts ?
ctx->opts->split_flags : COMMIT_GRAPH_SPLIT_UNSPECIFIED;
ctx->num_extra_edges = 0;
if (ctx->report_progress)
ctx->progress = start_delayed_progress(
commit-graph write: add itermediate progress Add progress output to sections of code between "Annotating[...]" and "Computing[...]generation numbers". This can collectively take 5-10 seconds on a large enough repository. On a test repository with I have with ~7 million commits and ~50 million objects we'll now emit: $ ~/g/git/git --exec-path=$HOME/g/git commit-graph write Finding commits for commit graph among packed objects: 100% (124763727/124763727), done. Loading known commits in commit graph: 100% (18989461/18989461), done. Expanding reachable commits in commit graph: 100% (18989507/18989461), done. Clearing commit marks in commit graph: 100% (18989507/18989507), done. Counting distinct commits in commit graph: 100% (18989507/18989507), done. Finding extra edges in commit graph: 100% (18989507/18989507), done. Computing commit graph generation numbers: 100% (7250302/7250302), done. Writing out commit graph in 4 passes: 100% (29001208/29001208), done. Whereas on a medium-sized repository such as linux.git these new progress bars won't have time to kick in and as before and we'll still emit output like: $ ~/g/git/git --exec-path=$HOME/g/git commit-graph write Finding commits for commit graph among packed objects: 100% (6529159/6529159), done. Expanding reachable commits in commit graph: 815990, done. Computing commit graph generation numbers: 100% (815983/815983), done. Writing out commit graph in 4 passes: 100% (3263932/3263932), done. The "Counting distinct commits in commit graph" phase will spend most of its time paused at "0/*" as we QSORT(...) the list. That's not optimal, but at least we don't seem to be stalling anymore most of the time. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-19 20:21:20 +00:00
_("Finding extra edges in commit graph"),
ctx->oids.nr);
for (i = 0; i < ctx->oids.nr; i++) {
unsigned int num_parents;
display_progress(ctx->progress, i + 1);
if (i > 0 && oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i]))
continue;
ALLOC_GROW(ctx->commits.list, ctx->commits.nr + 1, ctx->commits.alloc);
ctx->commits.list[ctx->commits.nr] = lookup_commit(ctx->r, &ctx->oids.list[i]);
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
if (ctx->split && flags != COMMIT_GRAPH_SPLIT_REPLACE &&
commit_graph_position(ctx->commits.list[ctx->commits.nr]) != COMMIT_NOT_FROM_GRAPH)
continue;
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
if (ctx->split && flags == COMMIT_GRAPH_SPLIT_REPLACE)
parse_commit(ctx->commits.list[ctx->commits.nr]);
else
parse_commit_no_graph(ctx->commits.list[ctx->commits.nr]);
num_parents = commit_list_count(ctx->commits.list[ctx->commits.nr]->parents);
if (num_parents > 2)
ctx->num_extra_edges += num_parents - 1;
ctx->commits.nr++;
}
stop_progress(&ctx->progress);
}
static int write_graph_chunk_base_1(struct hashfile *f,
struct commit_graph *g)
{
int num = 0;
if (!g)
return 0;
num = write_graph_chunk_base_1(f, g->base_graph);
hashwrite(f, g->oid.hash, the_hash_algo->rawsz);
return num + 1;
}
static int write_graph_chunk_base(struct hashfile *f,
struct write_commit_graph_context *ctx)
{
int num = write_graph_chunk_base_1(f, ctx->new_base_graph);
if (num != ctx->num_commit_graphs_after - 1) {
error(_("failed to write correct number of base graph ids"));
return -1;
}
return 0;
}
typedef int (*chunk_write_fn)(struct hashfile *f,
struct write_commit_graph_context *ctx);
struct chunk_info {
uint32_t id;
uint64_t size;
chunk_write_fn write_fn;
};
static int write_commit_graph_file(struct write_commit_graph_context *ctx)
{
uint32_t i;
int fd;
struct hashfile *f;
struct lock_file lk = LOCK_INIT;
struct chunk_info chunks[MAX_NUM_CHUNKS + 1];
const unsigned hashsz = the_hash_algo->rawsz;
struct strbuf progress_title = STRBUF_INIT;
int num_chunks = 3;
uint64_t chunk_offset;
struct object_id file_hash;
if (ctx->split) {
struct strbuf tmp_file = STRBUF_INIT;
strbuf_addf(&tmp_file,
"%s/info/commit-graphs/tmp_graph_XXXXXX",
commit-graph.h: store an odb in 'struct write_commit_graph_context' There are lots of places in 'commit-graph.h' where a function either has (or almost has) a full 'struct object_directory *', accesses '->path', and then throws away the rest of the struct. This can cause headaches when comparing the locations of object directories across alternates (e.g., in the case of deciding if two commit-graph layers can be merged). These paths are normalized with 'normalize_path_copy()' which mitigates some comparison issues, but not all [1]. Replace usage of 'char *object_dir' with 'odb->path' by storing a 'struct object_directory *' in the 'write_commit_graph_context' structure. This is an intermediate step towards getting rid of all path normalization in 'commit-graph.c'. Resolving a user-provided '--object-dir' argument now requires that we compare it to the known alternates for equality. Prior to this patch, an unknown '--object-dir' argument would silently exit with status zero. This can clearly lead to unintended behavior, such as verifying commit-graphs that aren't in a repository's own object store (or one of its alternates), or causing a typo to mask a legitimate commit-graph verification failure. Make this error non-silent by 'die()'-ing when the given '--object-dir' does not match any known alternate object store. [1]: In my testing, for example, I can get one side of the commit-graph code to fill object_dir with "./objects" and the other with just "objects". Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-04 05:51:50 +00:00
ctx->odb->path);
ctx->graph_name = strbuf_detach(&tmp_file, NULL);
} else {
commit-graph.c: remove path normalization, comparison As of the previous patch, all calls to 'commit-graph.c' functions which perform path normalization (for e.g., 'get_commit_graph_filename()') are of the form 'ctx->odb->path', which is always in normalized form. Now that there are no callers passing non-normalized paths to these functions, ensure that future callers are bound by the same restrictions by making these functions take a 'struct object_directory *' instead of a 'const char *'. To match, replace all calls with arguments of the form 'ctx->odb->path' with 'ctx->odb' To recover the path, functions that perform path manipulation simply use 'odb->path'. Further, avoid string comparisons with arguments of the form 'odb->path', and instead prefer raw pointer comparisons, which accomplish the same effect, but are far less brittle. This has a pleasant side-effect of making these functions much more robust to paths that cannot be normalized by 'normalize_path_copy()', i.e., because they are outside of the current working directory. For example, prior to this patch, Valgrind reports that the following uninitialized memory read [1]: $ ( cd t && GIT_DIR=../.git valgrind git rev-parse HEAD^ ) because 'normalize_path_copy()' can't normalize '../.git' (since it's relative to but above of the current working directory) [2]. By using a 'struct object_directory *' directly, 'get_commit_graph_filename()' does not need to normalize, because all paths are relative to the current working directory since they are always read from the '->path' of an object directory. [1]: https://lore.kernel.org/git/20191027042116.GA5801@sigill.intra.peff.net. [2]: The bug here is that 'get_commit_graph_filename()' returns the result of 'normalize_path_copy()' without checking the return value. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-03 21:18:02 +00:00
ctx->graph_name = get_commit_graph_filename(ctx->odb);
}
if (safe_create_leading_directories(ctx->graph_name)) {
UNLEAK(ctx->graph_name);
error(_("unable to create leading directories of %s"),
ctx->graph_name);
return -1;
}
if (ctx->split) {
char *lock_name = get_commit_graph_chain_filename(ctx->odb);
hold_lock_file_for_update_mode(&lk, lock_name,
LOCK_DIE_ON_ERROR, 0444);
fd = git_mkstemp_mode(ctx->graph_name, 0444);
if (fd < 0) {
error(_("unable to create temporary graph layer"));
return -1;
}
if (adjust_shared_perm(ctx->graph_name)) {
error(_("unable to adjust shared permissions for '%s'"),
ctx->graph_name);
return -1;
}
f = hashfd(fd, ctx->graph_name);
} else {
commit-graph.c: write non-split graphs as read-only In the previous commit, Git learned 'hold_lock_file_for_update_mode' to allow the caller to specify the permission bits (prior to further adjustment by the umask and shared repository permissions) used when acquiring a temporary file. Use this in the commit-graph machinery for writing a non-split graph to acquire an opened temporary file with permissions read-only permissions to match the split behavior. (In the split case, Git uses git_mkstemp_mode' for each of the commit-graph layers with permission bits '0444'). One can notice this discrepancy when moving a non-split graph to be part of a new chain. This causes a commit-graph chain where all layers have read-only permission bits, except for the base layer, which is writable for the current user. Resolve this discrepancy by using the new 'hold_lock_file_for_update_mode' and passing the desired permission bits. Doing so causes some test fallout in t5318 and t6600. In t5318, this occurs in tests that corrupt a commit-graph file by writing into it. For these, 'chmod u+w'-ing the file beforehand resolves the issue. The additional spot in 'corrupt_graph_verify' is necessary because of the extra 'git commit-graph write' beforehand (which *does* rewrite the commit-graph file). In t6600, this is caused by copying a read-only commit-graph file into place and then trying to replace it. For these, make these files writable. Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-29 17:36:38 +00:00
hold_lock_file_for_update_mode(&lk, ctx->graph_name,
LOCK_DIE_ON_ERROR, 0444);
fd = lk.tempfile->fd;
f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
}
chunks[0].id = GRAPH_CHUNKID_OIDFANOUT;
chunks[0].size = GRAPH_FANOUT_SIZE;
chunks[0].write_fn = write_graph_chunk_fanout;
chunks[1].id = GRAPH_CHUNKID_OIDLOOKUP;
chunks[1].size = hashsz * ctx->commits.nr;
chunks[1].write_fn = write_graph_chunk_oids;
chunks[2].id = GRAPH_CHUNKID_DATA;
chunks[2].size = (hashsz + 16) * ctx->commits.nr;
chunks[2].write_fn = write_graph_chunk_data;
if (ctx->num_extra_edges) {
chunks[num_chunks].id = GRAPH_CHUNKID_EXTRAEDGES;
chunks[num_chunks].size = 4 * ctx->num_extra_edges;
chunks[num_chunks].write_fn = write_graph_chunk_extra_edges;
num_chunks++;
}
if (ctx->changed_paths) {
chunks[num_chunks].id = GRAPH_CHUNKID_BLOOMINDEXES;
chunks[num_chunks].size = sizeof(uint32_t) * ctx->commits.nr;
chunks[num_chunks].write_fn = write_graph_chunk_bloom_indexes;
num_chunks++;
chunks[num_chunks].id = GRAPH_CHUNKID_BLOOMDATA;
chunks[num_chunks].size = sizeof(uint32_t) * 3
+ ctx->total_bloom_filter_data_size;
chunks[num_chunks].write_fn = write_graph_chunk_bloom_data;
num_chunks++;
}
if (ctx->num_commit_graphs_after > 1) {
chunks[num_chunks].id = GRAPH_CHUNKID_BASE;
chunks[num_chunks].size = hashsz * (ctx->num_commit_graphs_after - 1);
chunks[num_chunks].write_fn = write_graph_chunk_base;
num_chunks++;
}
chunks[num_chunks].id = 0;
chunks[num_chunks].size = 0;
hashwrite_be32(f, GRAPH_SIGNATURE);
hashwrite_u8(f, GRAPH_VERSION);
hashwrite_u8(f, oid_version());
hashwrite_u8(f, num_chunks);
hashwrite_u8(f, ctx->num_commit_graphs_after - 1);
chunk_offset = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
for (i = 0; i <= num_chunks; i++) {
uint32_t chunk_write[3];
chunk_write[0] = htonl(chunks[i].id);
chunk_write[1] = htonl(chunk_offset >> 32);
chunk_write[2] = htonl(chunk_offset & 0xffffffff);
hashwrite(f, chunk_write, 12);
chunk_offset += chunks[i].size;
}
if (ctx->report_progress) {
strbuf_addf(&progress_title,
Q_("Writing out commit graph in %d pass",
"Writing out commit graph in %d passes",
num_chunks),
num_chunks);
ctx->progress = start_delayed_progress(
progress_title.buf,
num_chunks * ctx->commits.nr);
}
for (i = 0; i < num_chunks; i++) {
uint64_t start_offset = f->total + f->offset;
if (chunks[i].write_fn(f, ctx))
return -1;
if (f->total + f->offset != start_offset + chunks[i].size)
BUG("expected to write %"PRId64" bytes to chunk %"PRIx32", but wrote %"PRId64" instead",
chunks[i].size, chunks[i].id,
f->total + f->offset - start_offset);
}
stop_progress(&ctx->progress);
strbuf_release(&progress_title);
if (ctx->split && ctx->base_graph_name && ctx->num_commit_graphs_after > 1) {
char *new_base_hash = xstrdup(oid_to_hex(&ctx->new_base_graph->oid));
commit-graph.c: remove path normalization, comparison As of the previous patch, all calls to 'commit-graph.c' functions which perform path normalization (for e.g., 'get_commit_graph_filename()') are of the form 'ctx->odb->path', which is always in normalized form. Now that there are no callers passing non-normalized paths to these functions, ensure that future callers are bound by the same restrictions by making these functions take a 'struct object_directory *' instead of a 'const char *'. To match, replace all calls with arguments of the form 'ctx->odb->path' with 'ctx->odb' To recover the path, functions that perform path manipulation simply use 'odb->path'. Further, avoid string comparisons with arguments of the form 'odb->path', and instead prefer raw pointer comparisons, which accomplish the same effect, but are far less brittle. This has a pleasant side-effect of making these functions much more robust to paths that cannot be normalized by 'normalize_path_copy()', i.e., because they are outside of the current working directory. For example, prior to this patch, Valgrind reports that the following uninitialized memory read [1]: $ ( cd t && GIT_DIR=../.git valgrind git rev-parse HEAD^ ) because 'normalize_path_copy()' can't normalize '../.git' (since it's relative to but above of the current working directory) [2]. By using a 'struct object_directory *' directly, 'get_commit_graph_filename()' does not need to normalize, because all paths are relative to the current working directory since they are always read from the '->path' of an object directory. [1]: https://lore.kernel.org/git/20191027042116.GA5801@sigill.intra.peff.net. [2]: The bug here is that 'get_commit_graph_filename()' returns the result of 'normalize_path_copy()' without checking the return value. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-03 21:18:02 +00:00
char *new_base_name = get_split_graph_filename(ctx->new_base_graph->odb, new_base_hash);
free(ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2]);
free(ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2]);
ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2] = new_base_name;
ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2] = new_base_hash;
}
close_commit_graph(ctx->r->objects);
finalize_hashfile(f, file_hash.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
if (ctx->split) {
FILE *chainf = fdopen_lock_file(&lk, "w");
char *final_graph_name;
int result;
close(fd);
if (!chainf) {
error(_("unable to open commit-graph chain file"));
return -1;
}
if (ctx->base_graph_name) {
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
const char *dest;
int idx = ctx->num_commit_graphs_after - 1;
if (ctx->num_commit_graphs_after > 1)
idx--;
dest = ctx->commit_graph_filenames_after[idx];
if (strcmp(ctx->base_graph_name, dest)) {
result = rename(ctx->base_graph_name, dest);
if (result) {
error(_("failed to rename base commit-graph file"));
return -1;
}
}
} else {
commit-graph.c: remove path normalization, comparison As of the previous patch, all calls to 'commit-graph.c' functions which perform path normalization (for e.g., 'get_commit_graph_filename()') are of the form 'ctx->odb->path', which is always in normalized form. Now that there are no callers passing non-normalized paths to these functions, ensure that future callers are bound by the same restrictions by making these functions take a 'struct object_directory *' instead of a 'const char *'. To match, replace all calls with arguments of the form 'ctx->odb->path' with 'ctx->odb' To recover the path, functions that perform path manipulation simply use 'odb->path'. Further, avoid string comparisons with arguments of the form 'odb->path', and instead prefer raw pointer comparisons, which accomplish the same effect, but are far less brittle. This has a pleasant side-effect of making these functions much more robust to paths that cannot be normalized by 'normalize_path_copy()', i.e., because they are outside of the current working directory. For example, prior to this patch, Valgrind reports that the following uninitialized memory read [1]: $ ( cd t && GIT_DIR=../.git valgrind git rev-parse HEAD^ ) because 'normalize_path_copy()' can't normalize '../.git' (since it's relative to but above of the current working directory) [2]. By using a 'struct object_directory *' directly, 'get_commit_graph_filename()' does not need to normalize, because all paths are relative to the current working directory since they are always read from the '->path' of an object directory. [1]: https://lore.kernel.org/git/20191027042116.GA5801@sigill.intra.peff.net. [2]: The bug here is that 'get_commit_graph_filename()' returns the result of 'normalize_path_copy()' without checking the return value. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-03 21:18:02 +00:00
char *graph_name = get_commit_graph_filename(ctx->odb);
unlink(graph_name);
}
ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(oid_to_hex(&file_hash));
commit-graph.c: remove path normalization, comparison As of the previous patch, all calls to 'commit-graph.c' functions which perform path normalization (for e.g., 'get_commit_graph_filename()') are of the form 'ctx->odb->path', which is always in normalized form. Now that there are no callers passing non-normalized paths to these functions, ensure that future callers are bound by the same restrictions by making these functions take a 'struct object_directory *' instead of a 'const char *'. To match, replace all calls with arguments of the form 'ctx->odb->path' with 'ctx->odb' To recover the path, functions that perform path manipulation simply use 'odb->path'. Further, avoid string comparisons with arguments of the form 'odb->path', and instead prefer raw pointer comparisons, which accomplish the same effect, but are far less brittle. This has a pleasant side-effect of making these functions much more robust to paths that cannot be normalized by 'normalize_path_copy()', i.e., because they are outside of the current working directory. For example, prior to this patch, Valgrind reports that the following uninitialized memory read [1]: $ ( cd t && GIT_DIR=../.git valgrind git rev-parse HEAD^ ) because 'normalize_path_copy()' can't normalize '../.git' (since it's relative to but above of the current working directory) [2]. By using a 'struct object_directory *' directly, 'get_commit_graph_filename()' does not need to normalize, because all paths are relative to the current working directory since they are always read from the '->path' of an object directory. [1]: https://lore.kernel.org/git/20191027042116.GA5801@sigill.intra.peff.net. [2]: The bug here is that 'get_commit_graph_filename()' returns the result of 'normalize_path_copy()' without checking the return value. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-03 21:18:02 +00:00
final_graph_name = get_split_graph_filename(ctx->odb,
ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1] = final_graph_name;
result = rename(ctx->graph_name, final_graph_name);
for (i = 0; i < ctx->num_commit_graphs_after; i++)
fprintf(lk.tempfile->fp, "%s\n", ctx->commit_graph_hash_after[i]);
if (result) {
error(_("failed to rename temporary commit-graph file"));
return -1;
}
}
commit_lock_file(&lk);
return 0;
}
static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
{
struct commit_graph *g;
uint32_t num_commits;
enum commit_graph_split_flags flags = COMMIT_GRAPH_SPLIT_UNSPECIFIED;
uint32_t i;
int max_commits = 0;
int size_mult = 2;
if (ctx->opts) {
max_commits = ctx->opts->max_commits;
if (ctx->opts->size_multiple)
size_mult = ctx->opts->size_multiple;
flags = ctx->opts->split_flags;
}
g = ctx->r->objects->commit_graph;
num_commits = ctx->commits.nr;
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
if (flags == COMMIT_GRAPH_SPLIT_REPLACE)
ctx->num_commit_graphs_after = 1;
else
ctx->num_commit_graphs_after = ctx->num_commit_graphs_before + 1;
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
if (flags != COMMIT_GRAPH_SPLIT_MERGE_PROHIBITED &&
flags != COMMIT_GRAPH_SPLIT_REPLACE) {
while (g && (g->num_commits <= size_mult * num_commits ||
(max_commits && num_commits > max_commits))) {
if (g->odb != ctx->odb)
break;
num_commits += g->num_commits;
g = g->base_graph;
ctx->num_commit_graphs_after--;
}
}
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
if (flags != COMMIT_GRAPH_SPLIT_REPLACE)
ctx->new_base_graph = g;
else if (ctx->num_commit_graphs_after != 1)
BUG("split_graph_merge_strategy: num_commit_graphs_after "
"should be 1 with --split=replace");
if (ctx->num_commit_graphs_after == 2) {
commit-graph.c: remove path normalization, comparison As of the previous patch, all calls to 'commit-graph.c' functions which perform path normalization (for e.g., 'get_commit_graph_filename()') are of the form 'ctx->odb->path', which is always in normalized form. Now that there are no callers passing non-normalized paths to these functions, ensure that future callers are bound by the same restrictions by making these functions take a 'struct object_directory *' instead of a 'const char *'. To match, replace all calls with arguments of the form 'ctx->odb->path' with 'ctx->odb' To recover the path, functions that perform path manipulation simply use 'odb->path'. Further, avoid string comparisons with arguments of the form 'odb->path', and instead prefer raw pointer comparisons, which accomplish the same effect, but are far less brittle. This has a pleasant side-effect of making these functions much more robust to paths that cannot be normalized by 'normalize_path_copy()', i.e., because they are outside of the current working directory. For example, prior to this patch, Valgrind reports that the following uninitialized memory read [1]: $ ( cd t && GIT_DIR=../.git valgrind git rev-parse HEAD^ ) because 'normalize_path_copy()' can't normalize '../.git' (since it's relative to but above of the current working directory) [2]. By using a 'struct object_directory *' directly, 'get_commit_graph_filename()' does not need to normalize, because all paths are relative to the current working directory since they are always read from the '->path' of an object directory. [1]: https://lore.kernel.org/git/20191027042116.GA5801@sigill.intra.peff.net. [2]: The bug here is that 'get_commit_graph_filename()' returns the result of 'normalize_path_copy()' without checking the return value. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-03 21:18:02 +00:00
char *old_graph_name = get_commit_graph_filename(g->odb);
if (!strcmp(g->filename, old_graph_name) &&
commit-graph.c: remove path normalization, comparison As of the previous patch, all calls to 'commit-graph.c' functions which perform path normalization (for e.g., 'get_commit_graph_filename()') are of the form 'ctx->odb->path', which is always in normalized form. Now that there are no callers passing non-normalized paths to these functions, ensure that future callers are bound by the same restrictions by making these functions take a 'struct object_directory *' instead of a 'const char *'. To match, replace all calls with arguments of the form 'ctx->odb->path' with 'ctx->odb' To recover the path, functions that perform path manipulation simply use 'odb->path'. Further, avoid string comparisons with arguments of the form 'odb->path', and instead prefer raw pointer comparisons, which accomplish the same effect, but are far less brittle. This has a pleasant side-effect of making these functions much more robust to paths that cannot be normalized by 'normalize_path_copy()', i.e., because they are outside of the current working directory. For example, prior to this patch, Valgrind reports that the following uninitialized memory read [1]: $ ( cd t && GIT_DIR=../.git valgrind git rev-parse HEAD^ ) because 'normalize_path_copy()' can't normalize '../.git' (since it's relative to but above of the current working directory) [2]. By using a 'struct object_directory *' directly, 'get_commit_graph_filename()' does not need to normalize, because all paths are relative to the current working directory since they are always read from the '->path' of an object directory. [1]: https://lore.kernel.org/git/20191027042116.GA5801@sigill.intra.peff.net. [2]: The bug here is that 'get_commit_graph_filename()' returns the result of 'normalize_path_copy()' without checking the return value. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-03 21:18:02 +00:00
g->odb != ctx->odb) {
ctx->num_commit_graphs_after = 1;
ctx->new_base_graph = NULL;
}
free(old_graph_name);
}
commit-graph.c: gracefully handle file descriptor exhaustion When writing a layered commit-graph, the commit-graph machinery uses 'commit_graph_filenames_after' and 'commit_graph_hash_after' to keep track of the layers in the chain that we are in the process of writing. When the number of commit-graph layers shrinks, we initialize all entries in the aforementioned arrays, because we know the structure of the new commit-graph chain immediately (since there are no new layers, there are no unknown hash values). But when the number of commit-graph layers grows (i.e., that 'num_commit_graphs_after > num_commit_graphs_before'), then we leave some entries in the filenames and hashes arrays as uninitialized, because we will fill them in later as those values become available. For instance, we rely on 'write_commit_graph_file's to store the filename and hash of the last layer in the new chain, which is the one that it is responsible for writing. But, it's possible that 'write_commit_graph_file' may fail, e.g., from file descriptor exhaustion. In this case it is possible that 'git_mkstemp_mode' will fail, and that function will return early *before* setting the values for the last commit-graph layer's filename and hash. This causes a number of upleasant side-effects. For instance, trying to 'free()' each entry in 'ctx->commit_graph_filenames_after' (and similarly for the hashes array) causes us to 'free()' uninitialized memory, since the area is allocated with 'malloc()' and is therefore subject to contain garbage (which is left alone when 'write_commit_graph_file' returns early). This can manifest in other issues, like a general protection fault, and/or leaving a stray 'commit-graph-chain.lock' around after the process dies. (The reasoning for this is still a mystery to me, since we'd otherwise usually expect the kernel to run tempfile.c's 'atexit()' handlers in the case of a normal death...) To resolve this, initialize the memory with 'CALLOC_ARRAY' so that uninitialized entries are filled with zeros, and can thus be 'free()'d as a noop instead of causing a fault. Helped-by: Jeff King <peff@peff.net> Helped-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-23 21:41:09 +00:00
CALLOC_ARRAY(ctx->commit_graph_filenames_after, ctx->num_commit_graphs_after);
CALLOC_ARRAY(ctx->commit_graph_hash_after, ctx->num_commit_graphs_after);
for (i = 0; i < ctx->num_commit_graphs_after &&
i < ctx->num_commit_graphs_before; i++)
ctx->commit_graph_filenames_after[i] = xstrdup(ctx->commit_graph_filenames_before[i]);
i = ctx->num_commit_graphs_before - 1;
g = ctx->r->objects->commit_graph;
while (g) {
if (i < ctx->num_commit_graphs_after)
ctx->commit_graph_hash_after[i] = xstrdup(oid_to_hex(&g->oid));
i--;
g = g->base_graph;
}
}
static void merge_commit_graph(struct write_commit_graph_context *ctx,
struct commit_graph *g)
{
uint32_t i;
uint32_t offset = g->num_commits_in_base;
ALLOC_GROW(ctx->commits.list, ctx->commits.nr + g->num_commits, ctx->commits.alloc);
for (i = 0; i < g->num_commits; i++) {
struct object_id oid;
struct commit *result;
display_progress(ctx->progress, i + 1);
load_oid_from_graph(g, i + offset, &oid);
/* only add commits if they still exist in the repo */
result = lookup_commit_reference_gently(ctx->r, &oid, 1);
if (result) {
ctx->commits.list[ctx->commits.nr] = result;
ctx->commits.nr++;
}
}
}
static int commit_compare(const void *_a, const void *_b)
{
const struct commit *a = *(const struct commit **)_a;
const struct commit *b = *(const struct commit **)_b;
return oidcmp(&a->object.oid, &b->object.oid);
}
static void sort_and_scan_merged_commits(struct write_commit_graph_context *ctx)
{
commit-graph: ignore duplicates when merging layers Thomas reported [1] that a "git fetch" command was failing with an error saying "unexpected duplicate commit id". The root cause is that they had fetch.writeCommitGraph enabled which generates commit-graph chains, and this instance was merging two layers that both contained the same commit ID. [1] https://lore.kernel.org/git/55f8f00c-a61c-67d4-889e-a9501c596c39@virtuell-zuhause.de/ The initial assumption is that Git would not write a commit ID into a commit-graph layer if it already exists in a lower commit-graph layer. Somehow, this specific case did get into that situation, leading to this error. While unexpected, this isn't actually invalid (as long as the two layers agree on the metadata for the commit). When we parse a commit that does not have a graph_pos in the commit_graph_data_slab, we use binary search in the commit-graph layers to find the commit and set graph_pos. That position is never used again in this case. However, when we parse a commit from the commit-graph file, we load its parents from the commit-graph and assign graph_pos at that point. If those parents were already parsed from the commit-graph, then nothing needs to be done. Otherwise, this graph_pos is a valid position in the commit-graph so we can parse the parents, when necessary. Thus, this die() is too aggressive. The easiest thing to do would be to ignore the duplicates. If we only ignore the duplicates, then we will produce a commit-graph that has identical commit IDs listed in adjacent positions. This excess data will never be removed from the commit-graph, which could cascade into significantly bloated file sizes. Thankfully, we can collapse the list to erase the duplicate commit pointers. This allows us to get the end result we want without extra memory costs and minimal CPU time. The root cause is due to disabling core.commitGraph, which prevents parsing commits from the lower layers during a 'git commit-graph write --split' command. Since we use the 'graph_pos' value to determine whether a commit is in a lower layer, we never discover that those commits are already in the commit-graph chain and add them to the top layer. This layer is then merged down, creating duplicates. The test added in t5324-split-commit-graph.sh fails without this change. However, we still have not completely removed the need for this duplicate check. That will come in a follow-up change. Reported-by: Thomas Braun <thomas.braun@virtuell-zuhause.de> Helped-by: Taylor Blau <me@ttaylorr.com> Co-authored-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-10-09 20:53:51 +00:00
uint32_t i, dedup_i = 0;
if (ctx->report_progress)
ctx->progress = start_delayed_progress(
_("Scanning merged commits"),
ctx->commits.nr);
QSORT(ctx->commits.list, ctx->commits.nr, commit_compare);
ctx->num_extra_edges = 0;
for (i = 0; i < ctx->commits.nr; i++) {
display_progress(ctx->progress, i);
if (i && oideq(&ctx->commits.list[i - 1]->object.oid,
&ctx->commits.list[i]->object.oid)) {
commit-graph: ignore duplicates when merging layers Thomas reported [1] that a "git fetch" command was failing with an error saying "unexpected duplicate commit id". The root cause is that they had fetch.writeCommitGraph enabled which generates commit-graph chains, and this instance was merging two layers that both contained the same commit ID. [1] https://lore.kernel.org/git/55f8f00c-a61c-67d4-889e-a9501c596c39@virtuell-zuhause.de/ The initial assumption is that Git would not write a commit ID into a commit-graph layer if it already exists in a lower commit-graph layer. Somehow, this specific case did get into that situation, leading to this error. While unexpected, this isn't actually invalid (as long as the two layers agree on the metadata for the commit). When we parse a commit that does not have a graph_pos in the commit_graph_data_slab, we use binary search in the commit-graph layers to find the commit and set graph_pos. That position is never used again in this case. However, when we parse a commit from the commit-graph file, we load its parents from the commit-graph and assign graph_pos at that point. If those parents were already parsed from the commit-graph, then nothing needs to be done. Otherwise, this graph_pos is a valid position in the commit-graph so we can parse the parents, when necessary. Thus, this die() is too aggressive. The easiest thing to do would be to ignore the duplicates. If we only ignore the duplicates, then we will produce a commit-graph that has identical commit IDs listed in adjacent positions. This excess data will never be removed from the commit-graph, which could cascade into significantly bloated file sizes. Thankfully, we can collapse the list to erase the duplicate commit pointers. This allows us to get the end result we want without extra memory costs and minimal CPU time. The root cause is due to disabling core.commitGraph, which prevents parsing commits from the lower layers during a 'git commit-graph write --split' command. Since we use the 'graph_pos' value to determine whether a commit is in a lower layer, we never discover that those commits are already in the commit-graph chain and add them to the top layer. This layer is then merged down, creating duplicates. The test added in t5324-split-commit-graph.sh fails without this change. However, we still have not completely removed the need for this duplicate check. That will come in a follow-up change. Reported-by: Thomas Braun <thomas.braun@virtuell-zuhause.de> Helped-by: Taylor Blau <me@ttaylorr.com> Co-authored-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-10-09 20:53:51 +00:00
/*
* Silently ignore duplicates. These were likely
* created due to a commit appearing in multiple
* layers of the chain, which is unexpected but
* not invalid. We should make sure there is a
* unique copy in the new layer.
*/
} else {
unsigned int num_parents;
commit-graph: ignore duplicates when merging layers Thomas reported [1] that a "git fetch" command was failing with an error saying "unexpected duplicate commit id". The root cause is that they had fetch.writeCommitGraph enabled which generates commit-graph chains, and this instance was merging two layers that both contained the same commit ID. [1] https://lore.kernel.org/git/55f8f00c-a61c-67d4-889e-a9501c596c39@virtuell-zuhause.de/ The initial assumption is that Git would not write a commit ID into a commit-graph layer if it already exists in a lower commit-graph layer. Somehow, this specific case did get into that situation, leading to this error. While unexpected, this isn't actually invalid (as long as the two layers agree on the metadata for the commit). When we parse a commit that does not have a graph_pos in the commit_graph_data_slab, we use binary search in the commit-graph layers to find the commit and set graph_pos. That position is never used again in this case. However, when we parse a commit from the commit-graph file, we load its parents from the commit-graph and assign graph_pos at that point. If those parents were already parsed from the commit-graph, then nothing needs to be done. Otherwise, this graph_pos is a valid position in the commit-graph so we can parse the parents, when necessary. Thus, this die() is too aggressive. The easiest thing to do would be to ignore the duplicates. If we only ignore the duplicates, then we will produce a commit-graph that has identical commit IDs listed in adjacent positions. This excess data will never be removed from the commit-graph, which could cascade into significantly bloated file sizes. Thankfully, we can collapse the list to erase the duplicate commit pointers. This allows us to get the end result we want without extra memory costs and minimal CPU time. The root cause is due to disabling core.commitGraph, which prevents parsing commits from the lower layers during a 'git commit-graph write --split' command. Since we use the 'graph_pos' value to determine whether a commit is in a lower layer, we never discover that those commits are already in the commit-graph chain and add them to the top layer. This layer is then merged down, creating duplicates. The test added in t5324-split-commit-graph.sh fails without this change. However, we still have not completely removed the need for this duplicate check. That will come in a follow-up change. Reported-by: Thomas Braun <thomas.braun@virtuell-zuhause.de> Helped-by: Taylor Blau <me@ttaylorr.com> Co-authored-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-10-09 20:53:51 +00:00
ctx->commits.list[dedup_i] = ctx->commits.list[i];
dedup_i++;
num_parents = commit_list_count(ctx->commits.list[i]->parents);
if (num_parents > 2)
commit-graph: fix bug around octopus merges In 1771be90 "commit-graph: merge commit-graph chains" (2019-06-18), the method sort_and_scan_merged_commits() was added to merge the commit lists of two commit-graph files in the incremental format. Unfortunately, there was an off-by-one error in that method around incrementing num_extra_edges, which leads to an incorrect offset for the base graph chunk. When we store an octopus merge in the commit-graph file, we store the first parent in the normal place, but use the second parent position to point into the "extra edges" chunk where the remaining parents exist. This means we should be adding "num_parents - 1" edges to this list, not "num_parents - 2". That is the basic error. The reason this was not caught in the test suite is more subtle. In 5324-split-commit-graph.sh, we test creating an octopus merge and adding it to the tip of a commit-graph chain, then verify the result. This _should_ have caught the problem, except that when we load the commit-graph files we were overly careful to not fail when the commit-graph chain does not match. This care was on purpose to avoid race conditions as one process reads the chain and another process modifies it. In such a case, the reading process outputs the following message to stderr: warning: commit-graph chain does not match These warnings are output in the test suite, but ignored. By checking the stderr of `git commit-graph verify` to include the expected progress output, it will now catch this error. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-05 16:43:41 +00:00
ctx->num_extra_edges += num_parents - 1;
}
}
commit-graph: ignore duplicates when merging layers Thomas reported [1] that a "git fetch" command was failing with an error saying "unexpected duplicate commit id". The root cause is that they had fetch.writeCommitGraph enabled which generates commit-graph chains, and this instance was merging two layers that both contained the same commit ID. [1] https://lore.kernel.org/git/55f8f00c-a61c-67d4-889e-a9501c596c39@virtuell-zuhause.de/ The initial assumption is that Git would not write a commit ID into a commit-graph layer if it already exists in a lower commit-graph layer. Somehow, this specific case did get into that situation, leading to this error. While unexpected, this isn't actually invalid (as long as the two layers agree on the metadata for the commit). When we parse a commit that does not have a graph_pos in the commit_graph_data_slab, we use binary search in the commit-graph layers to find the commit and set graph_pos. That position is never used again in this case. However, when we parse a commit from the commit-graph file, we load its parents from the commit-graph and assign graph_pos at that point. If those parents were already parsed from the commit-graph, then nothing needs to be done. Otherwise, this graph_pos is a valid position in the commit-graph so we can parse the parents, when necessary. Thus, this die() is too aggressive. The easiest thing to do would be to ignore the duplicates. If we only ignore the duplicates, then we will produce a commit-graph that has identical commit IDs listed in adjacent positions. This excess data will never be removed from the commit-graph, which could cascade into significantly bloated file sizes. Thankfully, we can collapse the list to erase the duplicate commit pointers. This allows us to get the end result we want without extra memory costs and minimal CPU time. The root cause is due to disabling core.commitGraph, which prevents parsing commits from the lower layers during a 'git commit-graph write --split' command. Since we use the 'graph_pos' value to determine whether a commit is in a lower layer, we never discover that those commits are already in the commit-graph chain and add them to the top layer. This layer is then merged down, creating duplicates. The test added in t5324-split-commit-graph.sh fails without this change. However, we still have not completely removed the need for this duplicate check. That will come in a follow-up change. Reported-by: Thomas Braun <thomas.braun@virtuell-zuhause.de> Helped-by: Taylor Blau <me@ttaylorr.com> Co-authored-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-10-09 20:53:51 +00:00
ctx->commits.nr = dedup_i;
stop_progress(&ctx->progress);
}
static void merge_commit_graphs(struct write_commit_graph_context *ctx)
{
struct commit_graph *g = ctx->r->objects->commit_graph;
uint32_t current_graph_number = ctx->num_commit_graphs_before;
while (g && current_graph_number >= ctx->num_commit_graphs_after) {
current_graph_number--;
if (ctx->report_progress)
ctx->progress = start_delayed_progress(_("Merging commit-graph"), 0);
merge_commit_graph(ctx, g);
stop_progress(&ctx->progress);
g = g->base_graph;
}
if (g) {
ctx->new_base_graph = g;
ctx->new_num_commits_in_base = g->num_commits + g->num_commits_in_base;
}
if (ctx->new_base_graph)
ctx->base_graph_name = xstrdup(ctx->new_base_graph->filename);
sort_and_scan_merged_commits(ctx);
}
static void mark_commit_graphs(struct write_commit_graph_context *ctx)
{
uint32_t i;
time_t now = time(NULL);
for (i = ctx->num_commit_graphs_after - 1; i < ctx->num_commit_graphs_before; i++) {
struct stat st;
struct utimbuf updated_time;
stat(ctx->commit_graph_filenames_before[i], &st);
updated_time.actime = st.st_atime;
updated_time.modtime = now;
utime(ctx->commit_graph_filenames_before[i], &updated_time);
}
}
static void expire_commit_graphs(struct write_commit_graph_context *ctx)
{
struct strbuf path = STRBUF_INIT;
DIR *dir;
struct dirent *de;
size_t dirnamelen;
timestamp_t expire_time = time(NULL);
if (ctx->opts && ctx->opts->expire_time)
expire_time = ctx->opts->expire_time;
if (!ctx->split) {
char *chain_file_name = get_commit_graph_chain_filename(ctx->odb);
unlink(chain_file_name);
free(chain_file_name);
ctx->num_commit_graphs_after = 0;
}
commit-graph.h: store an odb in 'struct write_commit_graph_context' There are lots of places in 'commit-graph.h' where a function either has (or almost has) a full 'struct object_directory *', accesses '->path', and then throws away the rest of the struct. This can cause headaches when comparing the locations of object directories across alternates (e.g., in the case of deciding if two commit-graph layers can be merged). These paths are normalized with 'normalize_path_copy()' which mitigates some comparison issues, but not all [1]. Replace usage of 'char *object_dir' with 'odb->path' by storing a 'struct object_directory *' in the 'write_commit_graph_context' structure. This is an intermediate step towards getting rid of all path normalization in 'commit-graph.c'. Resolving a user-provided '--object-dir' argument now requires that we compare it to the known alternates for equality. Prior to this patch, an unknown '--object-dir' argument would silently exit with status zero. This can clearly lead to unintended behavior, such as verifying commit-graphs that aren't in a repository's own object store (or one of its alternates), or causing a typo to mask a legitimate commit-graph verification failure. Make this error non-silent by 'die()'-ing when the given '--object-dir' does not match any known alternate object store. [1]: In my testing, for example, I can get one side of the commit-graph code to fill object_dir with "./objects" and the other with just "objects". Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-04 05:51:50 +00:00
strbuf_addstr(&path, ctx->odb->path);
strbuf_addstr(&path, "/info/commit-graphs");
dir = opendir(path.buf);
if (!dir)
goto out;
strbuf_addch(&path, '/');
dirnamelen = path.len;
while ((de = readdir(dir)) != NULL) {
struct stat st;
uint32_t i, found = 0;
strbuf_setlen(&path, dirnamelen);
strbuf_addstr(&path, de->d_name);
stat(path.buf, &st);
if (st.st_mtime > expire_time)
continue;
if (path.len < 6 || strcmp(path.buf + path.len - 6, ".graph"))
continue;
for (i = 0; i < ctx->num_commit_graphs_after; i++) {
if (!strcmp(ctx->commit_graph_filenames_after[i],
path.buf)) {
found = 1;
break;
}
}
if (!found)
unlink(path.buf);
}
out:
strbuf_release(&path);
}
commit-graph.h: store an odb in 'struct write_commit_graph_context' There are lots of places in 'commit-graph.h' where a function either has (or almost has) a full 'struct object_directory *', accesses '->path', and then throws away the rest of the struct. This can cause headaches when comparing the locations of object directories across alternates (e.g., in the case of deciding if two commit-graph layers can be merged). These paths are normalized with 'normalize_path_copy()' which mitigates some comparison issues, but not all [1]. Replace usage of 'char *object_dir' with 'odb->path' by storing a 'struct object_directory *' in the 'write_commit_graph_context' structure. This is an intermediate step towards getting rid of all path normalization in 'commit-graph.c'. Resolving a user-provided '--object-dir' argument now requires that we compare it to the known alternates for equality. Prior to this patch, an unknown '--object-dir' argument would silently exit with status zero. This can clearly lead to unintended behavior, such as verifying commit-graphs that aren't in a repository's own object store (or one of its alternates), or causing a typo to mask a legitimate commit-graph verification failure. Make this error non-silent by 'die()'-ing when the given '--object-dir' does not match any known alternate object store. [1]: In my testing, for example, I can get one side of the commit-graph code to fill object_dir with "./objects" and the other with just "objects". Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-04 05:51:50 +00:00
int write_commit_graph(struct object_directory *odb,
struct string_list *pack_indexes,
struct oidset *commits,
enum commit_graph_write_flags flags,
const struct commit_graph_opts *opts)
{
struct write_commit_graph_context *ctx;
uint32_t i, count_distinct = 0;
int res = 0;
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
int replace = 0;
struct bloom_filter_settings bloom_settings = DEFAULT_BLOOM_FILTER_SETTINGS;
prepare_repo_settings(the_repository);
if (!the_repository->settings.core_commit_graph) {
warning(_("attempting to write a commit-graph, but 'core.commitGraph' is disabled"));
return 0;
}
if (!commit_graph_compatible(the_repository))
return 0;
ctx = xcalloc(1, sizeof(struct write_commit_graph_context));
ctx->r = the_repository;
commit-graph.h: store an odb in 'struct write_commit_graph_context' There are lots of places in 'commit-graph.h' where a function either has (or almost has) a full 'struct object_directory *', accesses '->path', and then throws away the rest of the struct. This can cause headaches when comparing the locations of object directories across alternates (e.g., in the case of deciding if two commit-graph layers can be merged). These paths are normalized with 'normalize_path_copy()' which mitigates some comparison issues, but not all [1]. Replace usage of 'char *object_dir' with 'odb->path' by storing a 'struct object_directory *' in the 'write_commit_graph_context' structure. This is an intermediate step towards getting rid of all path normalization in 'commit-graph.c'. Resolving a user-provided '--object-dir' argument now requires that we compare it to the known alternates for equality. Prior to this patch, an unknown '--object-dir' argument would silently exit with status zero. This can clearly lead to unintended behavior, such as verifying commit-graphs that aren't in a repository's own object store (or one of its alternates), or causing a typo to mask a legitimate commit-graph verification failure. Make this error non-silent by 'die()'-ing when the given '--object-dir' does not match any known alternate object store. [1]: In my testing, for example, I can get one side of the commit-graph code to fill object_dir with "./objects" and the other with just "objects". Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-04 05:51:50 +00:00
ctx->odb = odb;
ctx->append = flags & COMMIT_GRAPH_WRITE_APPEND ? 1 : 0;
ctx->report_progress = flags & COMMIT_GRAPH_WRITE_PROGRESS ? 1 : 0;
ctx->split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0;
ctx->opts = opts;
ctx->total_bloom_filter_data_size = 0;
bloom_settings.bits_per_entry = git_env_ulong("GIT_TEST_BLOOM_SETTINGS_BITS_PER_ENTRY",
bloom_settings.bits_per_entry);
bloom_settings.num_hashes = git_env_ulong("GIT_TEST_BLOOM_SETTINGS_NUM_HASHES",
bloom_settings.num_hashes);
bloom_settings.max_changed_paths = git_env_ulong("GIT_TEST_BLOOM_SETTINGS_MAX_CHANGED_PATHS",
bloom_settings.max_changed_paths);
ctx->bloom_settings = &bloom_settings;
if (flags & COMMIT_GRAPH_WRITE_BLOOM_FILTERS)
ctx->changed_paths = 1;
if (!(flags & COMMIT_GRAPH_NO_WRITE_BLOOM_FILTERS)) {
struct commit_graph *g;
prepare_commit_graph_one(ctx->r, ctx->odb);
g = ctx->r->objects->commit_graph;
/* We have changed-paths already. Keep them in the next graph */
if (g && g->chunk_bloom_data) {
ctx->changed_paths = 1;
ctx->bloom_settings = g->bloom_filter_settings;
}
}
if (ctx->split) {
struct commit_graph *g;
prepare_commit_graph(ctx->r);
g = ctx->r->objects->commit_graph;
while (g) {
ctx->num_commit_graphs_before++;
g = g->base_graph;
}
if (ctx->num_commit_graphs_before) {
ALLOC_ARRAY(ctx->commit_graph_filenames_before, ctx->num_commit_graphs_before);
i = ctx->num_commit_graphs_before;
g = ctx->r->objects->commit_graph;
while (g) {
ctx->commit_graph_filenames_before[--i] = xstrdup(g->filename);
g = g->base_graph;
}
}
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
if (ctx->opts)
replace = ctx->opts->split_flags & COMMIT_GRAPH_SPLIT_REPLACE;
}
ctx->approx_nr_objects = approximate_object_count();
ctx->oids.alloc = ctx->approx_nr_objects / 32;
if (ctx->split && opts && ctx->oids.alloc > opts->max_commits)
ctx->oids.alloc = opts->max_commits;
if (ctx->append) {
prepare_commit_graph_one(ctx->r, ctx->odb);
if (ctx->r->objects->commit_graph)
ctx->oids.alloc += ctx->r->objects->commit_graph->num_commits;
}
if (ctx->oids.alloc < 1024)
ctx->oids.alloc = 1024;
ALLOC_ARRAY(ctx->oids.list, ctx->oids.alloc);
if (ctx->append && ctx->r->objects->commit_graph) {
struct commit_graph *g = ctx->r->objects->commit_graph;
for (i = 0; i < g->num_commits; i++) {
const unsigned char *hash = g->chunk_oid_lookup + g->hash_len * i;
hashcpy(ctx->oids.list[ctx->oids.nr++].hash, hash);
}
}
if (pack_indexes) {
ctx->order_by_pack = 1;
if ((res = fill_oids_from_packs(ctx, pack_indexes)))
goto cleanup;
}
if (commits) {
if ((res = fill_oids_from_commits(ctx, commits)))
commit-graph: error out on invalid commit oids in 'write --stdin-commits' While 'git commit-graph write --stdin-commits' expects commit object ids as input, it accepts and silently skips over any invalid commit object ids, and still exits with success: # nonsense $ echo not-a-commit-oid | git commit-graph write --stdin-commits $ echo $? 0 # sometimes I forgot that refs are not good... $ echo HEAD | git commit-graph write --stdin-commits $ echo $? 0 # valid tree OID, but not a commit OID $ git rev-parse HEAD^{tree} | git commit-graph write --stdin-commits $ echo $? 0 $ ls -l .git/objects/info/commit-graph ls: cannot access '.git/objects/info/commit-graph': No such file or directory Check that all input records are indeed valid commit object ids and return with error otherwise, the same way '--stdin-packs' handles invalid input; see e103f7276f (commit-graph: return with errors during write, 2019-06-12). Note that it should only return with error when encountering an invalid commit object id coming from standard input. However, '--reachable' uses the same code path to process object ids pointed to by all refs, and that includes tag object ids as well, which should still be skipped over. Therefore add a new flag to 'enum commit_graph_write_flags' and a corresponding field to 'struct write_commit_graph_context', so we can differentiate between those two cases. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Acked-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-05 08:02:40 +00:00
goto cleanup;
}
if (!pack_indexes && !commits) {
ctx->order_by_pack = 1;
fill_oids_from_all_packs(ctx);
}
close_reachable(ctx);
count_distinct = count_distinct_commits(ctx);
if (count_distinct >= GRAPH_EDGE_LAST_MASK) {
error(_("the commit graph format cannot write %d commits"), count_distinct);
res = -1;
goto cleanup;
}
ctx->commits.alloc = count_distinct;
ALLOC_ARRAY(ctx->commits.list, ctx->commits.alloc);
copy_oids_to_commits(ctx);
if (ctx->commits.nr >= GRAPH_EDGE_LAST_MASK) {
error(_("too many commits to write graph"));
res = -1;
goto cleanup;
}
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
if (!ctx->commits.nr && !replace)
goto cleanup;
if (ctx->split) {
split_graph_merge_strategy(ctx);
builtin/commit-graph.c: introduce split strategy 'replace' When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-14 04:04:17 +00:00
if (!replace)
merge_commit_graphs(ctx);
} else
ctx->num_commit_graphs_after = 1;
compute_generation_numbers(ctx);
if (ctx->changed_paths)
compute_bloom_filters(ctx);
res = write_commit_graph_file(ctx);
if (ctx->split)
mark_commit_graphs(ctx);
expire_commit_graphs(ctx);
cleanup:
free(ctx->graph_name);
free(ctx->commits.list);
free(ctx->oids.list);
if (ctx->commit_graph_filenames_after) {
for (i = 0; i < ctx->num_commit_graphs_after; i++) {
free(ctx->commit_graph_filenames_after[i]);
free(ctx->commit_graph_hash_after[i]);
}
for (i = 0; i < ctx->num_commit_graphs_before; i++)
free(ctx->commit_graph_filenames_before[i]);
free(ctx->commit_graph_filenames_after);
free(ctx->commit_graph_filenames_before);
free(ctx->commit_graph_hash_after);
}
free(ctx);
return res;
}
#define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
static int verify_commit_graph_error;
static void graph_report(const char *fmt, ...)
{
va_list ap;
verify_commit_graph_error = 1;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
fprintf(stderr, "\n");
va_end(ap);
}
#define GENERATION_ZERO_EXISTS 1
#define GENERATION_NUMBER_EXISTS 2
int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
{
uint32_t i, cur_fanout_pos = 0;
struct object_id prev_oid, cur_oid, checksum;
int generation_zero = 0;
struct hashfile *f;
int devnull;
struct progress *progress = NULL;
int local_error = 0;
if (!g) {
graph_report("no commit-graph file loaded");
return 1;
}
commit-graph: fix segfault on e.g. "git status" When core.commitGraph=true is set, various common commands now consult the commit graph. Because the commit-graph code is very trusting of its input data, it's possibly to construct a graph that'll cause an immediate segfault on e.g. "status" (and e.g. "log", "blame", ...). In some other cases where git immediately exits with a cryptic error about the graph being broken. The root cause of this is that while the "commit-graph verify" sub-command exhaustively verifies the graph, other users of the graph simply trust the graph, and will e.g. deference data found at certain offsets as pointers, causing segfaults. This change does the bare minimum to ensure that we don't segfault in the common fill_commit_in_graph() codepath called by e.g. setup_revisions(), to do this instrument the "commit-graph verify" tests to always check if "status" would subsequently segfault. This fixes the following tests which would previously segfault: not ok 50 - detect low chunk count not ok 51 - detect missing OID fanout chunk not ok 52 - detect missing OID lookup chunk not ok 53 - detect missing commit data chunk Those happened because with the commit-graph enabled setup_revisions() would eventually call fill_commit_in_graph(), where e.g. g->chunk_commit_data is used early as an offset (and will be 0x0). With this change we get far enough to detect that the graph is broken, and show an error instead. E.g.: $ git status; echo $? error: commit-graph is missing the Commit Data chunk 1 That also sucks, we should *warn* and not hard-fail "status" just because the commit-graph is corrupt, but fixing is left to a follow-up change. A side-effect of changing the reporting from graph_report() to error() is that we now have an "error: " prefix for these even for "commit-graph verify". Pseudo-diff before/after: $ git commit-graph verify -commit-graph is missing the Commit Data chunk +error: commit-graph is missing the Commit Data chunk Changing that is OK. Various errors it emits now early on are prefixed with "error: ", moving these over and changing the output doesn't break anything. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-25 12:08:29 +00:00
verify_commit_graph_error = verify_commit_graph_lite(g);
if (verify_commit_graph_error)
return verify_commit_graph_error;
devnull = open("/dev/null", O_WRONLY);
f = hashfd(devnull, NULL);
hashwrite(f, g->data, g->data_len - g->hash_len);
finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
}
for (i = 0; i < g->num_commits; i++) {
struct commit *graph_commit;
hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
graph_report(_("commit-graph has incorrect OID order: %s then %s"),
oid_to_hex(&prev_oid),
oid_to_hex(&cur_oid));
oidcpy(&prev_oid, &cur_oid);
while (cur_oid.hash[0] > cur_fanout_pos) {
uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
if (i != fanout_value)
graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
cur_fanout_pos, fanout_value, i);
cur_fanout_pos++;
}
graph_commit = lookup_commit(r, &cur_oid);
if (!parse_commit_in_graph_one(r, g, graph_commit))
graph_report(_("failed to parse commit %s from commit-graph"),
oid_to_hex(&cur_oid));
}
while (cur_fanout_pos < 256) {
uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
if (g->num_commits != fanout_value)
graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
cur_fanout_pos, fanout_value, i);
cur_fanout_pos++;
}
if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
return verify_commit_graph_error;
if (flags & COMMIT_GRAPH_WRITE_PROGRESS)
progress = start_progress(_("Verifying commits in commit graph"),
g->num_commits);
for (i = 0; i < g->num_commits; i++) {
struct commit *graph_commit, *odb_commit;
struct commit_list *graph_parents, *odb_parents;
uint32_t max_generation = 0;
uint32_t generation;
display_progress(progress, i + 1);
hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
graph_commit = lookup_commit(r, &cur_oid);
odb_commit = (struct commit *)create_object(r, &cur_oid, alloc_commit_node(r));
if (parse_commit_internal(odb_commit, 0, 0)) {
graph_report(_("failed to parse commit %s from object database for commit-graph"),
oid_to_hex(&cur_oid));
continue;
}
if (!oideq(&get_commit_tree_in_graph_one(r, g, graph_commit)->object.oid,
get_commit_tree_oid(odb_commit)))
graph_report(_("root tree OID for commit %s in commit-graph is %s != %s"),
oid_to_hex(&cur_oid),
oid_to_hex(get_commit_tree_oid(graph_commit)),
oid_to_hex(get_commit_tree_oid(odb_commit)));
graph_parents = graph_commit->parents;
odb_parents = odb_commit->parents;
while (graph_parents) {
if (odb_parents == NULL) {
graph_report(_("commit-graph parent list for commit %s is too long"),
oid_to_hex(&cur_oid));
break;
}
/* parse parent in case it is in a base graph */
parse_commit_in_graph_one(r, g, graph_parents->item);
if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
graph_report(_("commit-graph parent for %s is %s != %s"),
oid_to_hex(&cur_oid),
oid_to_hex(&graph_parents->item->object.oid),
oid_to_hex(&odb_parents->item->object.oid));
generation = commit_graph_generation(graph_parents->item);
if (generation > max_generation)
max_generation = generation;
graph_parents = graph_parents->next;
odb_parents = odb_parents->next;
}
if (odb_parents != NULL)
graph_report(_("commit-graph parent list for commit %s terminates early"),
oid_to_hex(&cur_oid));
if (!commit_graph_generation(graph_commit)) {
if (generation_zero == GENERATION_NUMBER_EXISTS)
graph_report(_("commit-graph has generation number zero for commit %s, but non-zero elsewhere"),
oid_to_hex(&cur_oid));
generation_zero = GENERATION_ZERO_EXISTS;
} else if (generation_zero == GENERATION_ZERO_EXISTS)
graph_report(_("commit-graph has non-zero generation number for commit %s, but zero elsewhere"),
oid_to_hex(&cur_oid));
if (generation_zero == GENERATION_ZERO_EXISTS)
continue;
/*
* If one of our parents has generation GENERATION_NUMBER_MAX, then
* our generation is also GENERATION_NUMBER_MAX. Decrement to avoid
* extra logic in the following condition.
*/
if (max_generation == GENERATION_NUMBER_MAX)
max_generation--;
generation = commit_graph_generation(graph_commit);
if (generation != max_generation + 1)
graph_report(_("commit-graph generation for commit %s is %u != %u"),
oid_to_hex(&cur_oid),
generation,
max_generation + 1);
if (graph_commit->date != odb_commit->date)
graph_report(_("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime),
oid_to_hex(&cur_oid),
graph_commit->date,
odb_commit->date);
}
stop_progress(&progress);
local_error = verify_commit_graph_error;
if (!(flags & COMMIT_GRAPH_VERIFY_SHALLOW) && g->base_graph)
local_error |= verify_commit_graph(r, g->base_graph, flags);
return local_error;
}
void free_commit_graph(struct commit_graph *g)
{
if (!g)
return;
if (g->data) {
munmap((void *)g->data, g->data_len);
g->data = NULL;
}
free(g->filename);
free(g->bloom_filter_settings);
free(g);
}
upload-pack: disable commit graph more gently for shallow traversal When the client has asked for certain shallow options like "deepen-since", we do a custom rev-list walk that pretends to be shallow. Before doing so, we have to disable the commit-graph, since it is not compatible with the shallow view of the repository. That's handled by 829a321569 (commit-graph: close_commit_graph before shallow walk, 2018-08-20). That commit literally closes and frees our repo->objects->commit_graph struct. That creates an interesting problem for commits that have _already_ been parsed using the commit graph. Their commit->object.parsed flag is set, their commit->graph_pos is set, but their commit->maybe_tree may still be NULL. When somebody later calls repo_get_commit_tree(), we see that we haven't loaded the tree oid yet and try to get it from the commit graph. But since it has been freed, we segfault! So the root of the issue is a data dependency between the commit's lazy-load of the tree oid and the fact that the commit graph can go away mid-process. How can we resolve it? There are a couple of general approaches: 1. The obvious answer is to avoid loading the tree from the graph when we see that it's NULL. But then what do we return for the tree oid? If we return NULL, our caller in do_traverse() will rightly complain that we have no tree. We'd have to fallback to loading the actual commit object and re-parsing it. That requires teaching parse_commit_buffer() to understand re-parsing (i.e., not starting from a clean slate and not leaking any allocated bits like parent list pointers). 2. When we close the commit graph, walk through the set of in-memory objects and clear any graph_pos pointers. But this means we also have to "unparse" any such commits so that we know they still need to open the commit object to fill in their trees. So it's no less complicated than (1), and is more expensive (since we clear objects we might not later need). 3. Stop freeing the commit-graph struct. Continue to let it be used for lazy-loads of tree oids, but let upload-pack specify that it shouldn't be used for further commit parsing. 4. Push the whole shallow rev-list out to its own sub-process, with the commit-graph disabled from the start, giving it a clean memory space to work from. I've chosen (3) here. Options (1) and (2) would work, but are non-trivial to implement. Option (4) is more expensive, and I'm not sure how complicated it is (shelling out for the actual rev-list part is easy, but we do then parse the resulting commits internally, and I'm not clear which parts need to be handling shallow-ness). The new test in t5500 triggers this segfault, but see the comments there for how horribly intimate it has to be with how both upload-pack and commit graphs work. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-09-12 14:44:45 +00:00
void disable_commit_graph(struct repository *r)
{
r->commit_graph_disabled = 1;
}