Commit graph

692 commits

Author SHA1 Message Date
René Scharfe
7431842325 use fspathhash() everywhere
cf2dc1c238 (speed up alt_odb_usable() with many alternates, 2021-07-07)
introduced the function fspathhash() for calculating path hashes while
respecting the configuration option core.ignorecase.  Call it instead of
open-coding it; the resulting code is shorter and less repetitive.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-30 12:14:27 -07:00
Junio C Hamano
268055bfde Merge branch 'en/rename-limits-doc'
Documentation on "git diff -l<n>" and diff.renameLimit have been
updated, and the defaults for these limits have been raised.

* en/rename-limits-doc:
  rename: bump limit defaults yet again
  diffcore-rename: treat a rename_limit of 0 as unlimited
  doc: clarify documentation for rename/copy limits
  diff: correct warning message when renameLimit exceeded
2021-07-28 13:18:03 -07:00
Junio C Hamano
dd6d3c90ee Merge branch 'ab/attribute-format'
Many "printf"-like helper functions we have have been annotated
with __attribute__() to catch placeholder/parameter mismatches.

* ab/attribute-format:
  advice.h: add missing __attribute__((format)) & fix usage
  *.h: add a few missing __attribute__((format))
  *.c static functions: add missing __attribute__((format))
  sequencer.c: move static function to avoid forward decl
  *.c static functions: don't forward-declare __attribute__
2021-07-28 13:17:59 -07:00
Junio C Hamano
bd4232fac3 Merge branch 'ab/struct-init'
Code cleanup around struct_type_init() functions.

* ab/struct-init:
  string-list.h users: change to use *_{nodup,dup}()
  string-list.[ch]: add a string_list_init_{nodup,dup}()
  dir.[ch]: replace dir_init() with DIR_INIT
  *.c *_init(): define in terms of corresponding *_INIT macro
  *.h: move some *_INIT to designated initializers
2021-07-16 17:42:53 -07:00
Junio C Hamano
d3b88be1b4 Merge branch 'en/merge-dir-rename-corner-case-fix'
The merge code had funny interactions between content based rename
detection and directory rename detection.

* en/merge-dir-rename-corner-case-fix:
  merge-recursive: handle rename-to-self case
  merge-ort: ensure we consult df_conflict and path_conflicts
  t6423: test directory renames causing rename-to-self
2021-07-16 17:42:45 -07:00
Elijah Newren
94b82d5686 rename: bump limit defaults yet again
These were last bumped in commit 92c57e5c1d (bump rename limit
defaults (again), 2011-02-19), and were bumped both because processors
had gotten faster, and because people were getting ugly merges that
caused problems and reporting it to the mailing list (suggesting that
folks were willing to spend more time waiting).

Since that time:
  * Linus has continued recommending kernel folks to set
    diff.renameLimit=0 (maps to 32767, currently)
  * Folks with repositories with lots of renames were happy to set
    merge.renameLimit above 32767, once the code supported that, to
    get correct cherry-picks
  * Processors have gotten faster
  * It has been discovered that the timing methodology used last time
    probably used too large example files.

The last point is probably worth explaining a bit more:

  * The "average" file size used appears to have been average blob size
    in the linux kernel history at the time (probably v2.6.25 or
    something close to it).
  * Since bigger files are modified more frequently, such a computation
    weights towards larger files.
  * Larger files may be more likely to be modified over time, but are
    not more likely to be renamed -- the mean and median blob size
    within a tree are a bit higher than the mean and median of blob
    sizes in the history leading up to that version for the linux
    kernel.
  * The mean blob size in v2.6.25 was half the average blob size in
    history leading to that point
  * The median blob size in v2.6.25 was about 40% of the mean blob size
    in v2.6.25.
  * Since the mean blob size is more than double the median blob size,
    any file as big as the mean will not be compared to any files of
    median size or less (because they'd be more than 50% dissimilar).
  * Since it is the number of files compared that provides the O(n^2)
    behavior, median-sized files should matter more than mean-sized
    ones.

The combined effect of the above is that the file size used in past
calculations was likely about 5x too large.  Combine that with a CPU
performance improvement of ~30%, and we can increase the limits by
a factor of sqrt(5/(1-.3)) = 2.67, while keeping the original stated
time limits.

Keeping the same approximate time limit probably makes sense for
diff.renameLimit (there is no progress feedback in e.g. git log -p),
but the experience above suggests merge.renameLimit could be extended
significantly.  In fact, it probably would make sense to have an
unlimited default setting for merge.renameLimit, but that would
likely need to be coupled with changes to how progress is displayed.
(See https://lore.kernel.org/git/YOx+Ok%2FEYvLqRMzJ@coredump.intra.peff.net/
for details in that area.)  For now, let's just bump the approximate
time limit from 10s to 1m.

(Note: We do not want to use actual time limits, because getting results
that depend on how loaded your system is that day feels bad, and because
we don't discover that we won't get all the renames until after we've
put in a lot of work rather than just upfront telling the user there are
too many files involved.)

Using the original time limit of 2s for diff.renameLimit, and bumping
merge.renameLimit from 10s to 60s, I found the following timings using
the simple script at the end of this commit message (on an AWS c5.xlarge
which reports as "Intel(R) Xeon(R) Platinum 8124M CPU @ 3.00GHz"):

      N   Timing
   1300    1.995s
   7100   59.973s

So let's round down to nice even numbers and bump the limits from
400->1000, and from 1000->7000.

Here is the measure_rename_perf script (adapted from
https://lore.kernel.org/git/20080211113516.GB6344@coredump.intra.peff.net/
in particular to avoid triggering the linear handling from
basename-guided rename detection):

    #!/bin/bash

    n=$1; shift

    rm -rf repo
    mkdir repo && cd repo
    git init -q -b main

    mkdata() {
      mkdir $1
      for i in `seq 1 $2`; do
        (sed "s/^/$i /" <../sample
         echo tag: $1
        ) >$1/$i
      done
    }

    mkdata initial $n
    git add .
    git commit -q -m initial

    mkdata new $n
    git add .
    cd new
    for i in *; do git mv $i $i.renamed; done
    cd ..
    git rm -q -rf initial
    git commit -q -m new

    time git diff-tree -M -l0 --summary HEAD^ HEAD

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-15 16:54:34 -07:00
Ævar Arnfjörð Bjarmason
48ca53cac4 *.c static functions: add missing __attribute__((format))
Add missing __attribute__((format)) function attributes to various
"static" functions that take printf arguments.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-13 15:20:20 -07:00
Ævar Arnfjörð Bjarmason
bc40dfb10a string-list.h users: change to use *_{nodup,dup}()
Change all in-tree users of the string_list_init(LIST, BOOL) API to
use string_list_init_{nodup,dup}(LIST) instead.

As noted in the preceding commit let's leave the now-unused
string_list_init() wrapper in-place for any in-flight users, it can be
removed at some later date.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-01 12:32:22 -07:00
Elijah Newren
3585d0ea23 merge-recursive: handle rename-to-self case
Directory rename detection can cause transitive renames, e.g. if the two
different sides of history each do one half of:
    A/file -> B/file
    B/     -> C/
then directory rename detection transitively renames to give us
    A/file -> C/file

However, when C/ == A/, note that this gives us
    A/file -> A/file.

merge-recursive assumed that any rename D -> E would have D != E.  While
that is almost always true, the above is a special case where it is not.
So we cannot do things like delete the rename source, we cannot assume
that a file existing at path E implies a rename/add conflict and we have
to be careful about what stages end up in the output.

This change feels a bit hackish.  It took me surprisingly many hours to
find, and given merge-recursive's design causing it to attempt to
enumerate all combinations of edge and corner cases with special code
for each combination, I'm worried there are other similar fixes needed
elsewhere if we can just come up with the right special testcase.
Perhaps an audit would rule it out, but I have not the energy.
merge-recursive deserves to die, and since it is on its way out anyway,
fixing this particular bug narrowly will have to be good enough.

Reported-by: Anders Kaseorg <andersk@mit.edu>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-06-30 14:40:10 -07:00
Andrei Rybak
abcb66c614 *: fix typos which duplicate a word
Fix typos in documentation, code comments, and RelNotes which repeat
various words.  In trivial cases, just delete the duplicated word and
rewrap text, if needed.  Reword the affected sentence in
Documentation/RelNotes/1.8.4.txt for it to make sense.

Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-06-14 10:16:06 +09:00
Junio C Hamano
5feebddd86 Merge branch 'js/merge-already-up-to-date-message-reword'
A few variants of informational message "Already up-to-date" has
been rephrased.

* js/merge-already-up-to-date-message-reword:
  merge: fix swapped "up to date" message components
  merge(s): apply consistent punctuation to "up to date" messages
2021-05-11 15:27:22 +09:00
Junio C Hamano
aaa3c8065d Merge branch 'bc/hash-transition-interop-part-1'
SHA-256 transition.

* bc/hash-transition-interop-part-1:
  hex: print objects using the hash algorithm member
  hex: default to the_hash_algo on zero algorithm value
  builtin/pack-objects: avoid using struct object_id for pack hash
  commit-graph: don't store file hashes as struct object_id
  builtin/show-index: set the algorithm for object IDs
  hash: provide per-algorithm null OIDs
  hash: set, copy, and use algo field in struct object_id
  builtin/pack-redundant: avoid casting buffers to struct object_id
  Use the final_oid_fn to finalize hashing of object IDs
  hash: add a function to finalize object IDs
  http-push: set algorithm when reading object ID
  Always use oidread to read into struct object_id
  hash: add an algo member to struct object_id
2021-05-10 16:59:46 +09:00
Eric Sunshine
80cde95eec merge(s): apply consistent punctuation to "up to date" messages
Although the various "Already up to date" messages resulting from merge
attempts share identical phrasing, they use a mix of punctuation ranging
from "." to "!" and even "Yeeah!", which leads to extra work for
translators. Ease the job of translators by settling upon "." as
punctuation for all such messages.

While at it, take advantage of printf_ln() to further ease the
translation task so translators need not worry about line termination,
and fix a case of missing line termination in the (unused)
merge_ort_nonrecursive() function.

Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-03 14:14:56 +09:00
Junio C Hamano
8e97852919 Merge branch 'ds/sparse-index-protections'
Builds on top of the sparse-index infrastructure to mark operations
that are not ready to mark with the sparse index, causing them to
fall back on fully-populated index that they always have worked with.

* ds/sparse-index-protections: (47 commits)
  name-hash: use expand_to_path()
  sparse-index: expand_to_path()
  name-hash: don't add directories to name_hash
  revision: ensure full index
  resolve-undo: ensure full index
  read-cache: ensure full index
  pathspec: ensure full index
  merge-recursive: ensure full index
  entry: ensure full index
  dir: ensure full index
  update-index: ensure full index
  stash: ensure full index
  rm: ensure full index
  merge-index: ensure full index
  ls-files: ensure full index
  grep: ensure full index
  fsck: ensure full index
  difftool: ensure full index
  commit: ensure full index
  checkout: ensure full index
  ...
2021-04-30 13:50:26 +09:00
brian m. carlson
14228447c9 hash: provide per-algorithm null OIDs
Up until recently, object IDs did not have an algorithm member, only a
hash.  Consequently, it was possible to share one null (all-zeros)
object ID among all hash algorithms.  Now that we're going to be
handling objects from multiple hash algorithms, it's important to make
sure that all object IDs have a correct algorithm field.

Introduce a per-algorithm null OID, and add it to struct hash_algo.
Introduce a wrapper function as well, and use it everywhere we used to
use the null_oid constant.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-27 16:31:39 +09:00
Junio C Hamano
7bec8e7fa6 Merge branch 'en/ort-readiness'
Plug the ort merge backend throughout the rest of the system, and
start testing it as a replacement for the recursive backend.

* en/ort-readiness:
  Add testing with merge-ort merge strategy
  t6423: mark remaining expected failure under merge-ort as such
  Revert "merge-ort: ignore the directory rename split conflict for now"
  merge-recursive: add a bunch of FIXME comments documenting known bugs
  merge-ort: write $GIT_DIR/AUTO_MERGE whenever we hit a conflict
  t: mark several submodule merging tests as fixed under merge-ort
  merge-ort: implement CE_SKIP_WORKTREE handling with conflicted entries
  t6428: new test for SKIP_WORKTREE handling and conflicts
  merge-ort: support subtree shifting
  merge-ort: let renormalization change modify/delete into clean delete
  merge-ort: have ll_merge() use a special attr_index for renormalization
  merge-ort: add a special minimal index just for renormalization
  merge-ort: use STABLE_QSORT instead of QSORT where required
2021-04-16 13:53:34 -07:00
Derrick Stolee
f7ef64be0c merge-recursive: ensure full index
Before iterating over all cache entries, ensure that a sparse index is
expanded to a full index to avoid unexpected behavior.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14 13:47:37 -07:00
Derrick Stolee
847a9e5d4f *: remove 'const' qualifier for struct index_state
Several methods specify that they take a 'struct index_state' pointer
with the 'const' qualifier because they intend to only query the data,
not change it. However, we will be introducing a step very low in the
method stack that might modify a sparse-index to become a full index in
the case that our queries venture inside a sparse-directory entry.

This change only removes the 'const' qualifiers that are necessary for
the following change which will actually modify the implementation of
index_name_stage_pos().

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14 13:46:00 -07:00
Junio C Hamano
ad16f748f2 Merge branch 'ab/read-tree'
Code simplification by removing support for a caller that is long gone.

* ab/read-tree:
  tree.h API: simplify read_tree_recursive() signature
  tree.h API: expose read_tree_1() as read_tree_at()
  archive: stop passing "stage" through read_tree_recursive()
  ls-files: refactor away read_tree()
  ls-files: don't needlessly pass around stage variable
  tree.c API: move read_tree() into builtin/ls-files.c
  ls-files tests: add meaningful --with-tree tests
  show tests: add test for "git show <tree>"
2021-03-30 14:35:37 -07:00
Ævar Arnfjörð Bjarmason
47957485b3 tree.h API: simplify read_tree_recursive() signature
Simplify the signature of read_tree_recursive() to omit the "base",
"baselen" and "stage" arguments. No callers of it use these parameters
for anything anymore.

The last function to call read_tree_recursive() with a non-"" path was
read_tree_recursive() itself, but that was changed in
ffd31f661d (Reimplement read_tree_recursive() using
tree_entry_interesting(), 2011-03-25).

The last user of the "stage" parameter went away in the last commit,
and even that use was mere boilerplate.

So let's remove those and rename the read_tree_recursive() function to
just read_tree(). We had another read_tree() function that I've
refactored away in preceding commits, since all in-tree users read
trees recursively with a callback we can change the name to signify
that this is the norm.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-20 16:09:26 -07:00
Elijah Newren
816147e7ba merge-recursive: add a bunch of FIXME comments documenting known bugs
The plan is to just delete merge-recursive, but not until everyone is
comfortable with merge-ort as a replacement.  Given that I haven't
switched all callers of merge-recursive over yet (e.g. git-am still uses
merge-recursive), maybe there's some value documenting known bugs in the
algorithm in case we end up keeping it or someone wants to dig it up in
the future.

Signed-off-by: Elijah Newren <newren@gmail.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-20 12:35:40 -07:00
René Scharfe
ca56dadb4b use CALLOC_ARRAY
Add and apply a semantic patch for converting code that open-codes
CALLOC_ARRAY to use it instead.  It shortens the code and infers the
element size automatically.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-13 16:00:09 -08:00
Elijah Newren
b0ca120554 commit: move reverse_commit_list() from merge-recursive
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-16 21:56:39 -08:00
Elijah Newren
6da1a25814 hashmap: provide deallocation function names
hashmap_free(), hashmap_free_entries(), and hashmap_free_() have existed
for a while, but aren't necessarily the clearest names, especially with
hashmap_partial_clear() being added to the mix and lazy-initialization
now being supported.  Peff suggested we adopt the following names[1]:

  - hashmap_clear() - remove all entries and de-allocate any
    hashmap-specific data, but be ready for reuse

  - hashmap_clear_and_free() - ditto, but free the entries themselves

  - hashmap_partial_clear() - remove all entries but don't deallocate
    table

  - hashmap_partial_clear_and_free() - ditto, but free the entries

This patch provides the new names and converts all existing callers over
to the new naming scheme.

[1] https://lore.kernel.org/git/20201030125059.GA3277724@coredump.intra.peff.net/

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-02 12:15:50 -08:00
Junio C Hamano
4339259d5f Merge branch 'en/eol-attrs-gotchas'
All "mergy" operations that internally use the merge-recursive
machinery should honor the merge.renormalize configuration, but
many of them didn't.

* en/eol-attrs-gotchas:
  checkout: support renormalization with checkout -m <paths>
  merge: make merge.renormalize work for all uses of merge machinery
  t6038: remove problematic test
  t6038: make tests fail for the right reason
2020-08-10 10:24:02 -07:00
Elijah Newren
8d552258f4 merge: make merge.renormalize work for all uses of merge machinery
The 'merge' command is not the only one that does merges; other commands
like checkout -m or rebase do as well.  Unfortunately, the only area of
the code that checked for the "merge.renormalize" config setting was in
builtin/merge.c, meaning it could only affect merges performed by the
"merge" command.  Move the handling of this config setting to
merge_recursive_config() so that other commands can benefit from it as
well.  Fixes a few tests in t6038.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-03 11:48:15 -07:00
Elijah Newren
56e743426b merge-recursive: fix unclear and outright wrong comments
Commits 7c0a6c8e47 ("merge-recursive: move some definitions around to
clean up the header", 2019-08-17), and b4db8a2b76 ("merge-recursive:
remove useless parameter in merge_trees()", 2019-08-17) added some
useful documentation to the functions, but had a few places where the
new comments were unclear or even misleading.  Fix those comments.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-02 11:03:57 -07:00
Elijah Newren
95983da6b4 merge-recursive: fix rename/rename(1to2) for working tree with a binary
With a rename/rename(1to2) conflict, we attempt to do a three-way merge
of the file contents, so that the correct contents can be placed in the
working tree at both paths.  If the file is a binary, however, no
content merging is possible and we should just use the original version
of the file at each of the paths.

Reported-by: Chunlin Zhang <zhangchunlin@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-14 12:14:19 -07:00
brian m. carlson
ab90ecae99 convert: permit passing additional metadata to filter processes
There are a variety of situations where a filter process can make use of
some additional metadata.  For example, some people find the ident
filter too limiting and would like to include the commit or the branch
in their smudged files.  This information isn't available during
checkout as HEAD hasn't been updated at that point, and it wouldn't be
available in archives either.

Let's add a way to pass this metadata down to the filter.  We pass the
blob we're operating on, the treeish (preferring the commit over the
tree if one exists), and the ref we're operating on.  Note that we won't
pass this information in all cases, such as when renormalizing or when
we're performing diffs, since it doesn't make sense in those cases.

The data we currently get from the filter process looks like the
following:

  command=smudge
  pathname=git.c
  0000

With this change, we'll get data more like this:

  command=smudge
  pathname=git.c
  refname=refs/tags/v2.25.1
  treeish=c522f061d551c9bb8684a7c3859b2ece4499b56b
  blob=7be7ad34bd053884ec48923706e70c81719a8660
  0000

There are a couple things to note about this approach.  For operations
like checkout, treeish will always be a commit, since we cannot check
out individual trees, but for other operations, like archive, we can end
up operating on only a particular tree, so we'll provide only a tree as
the treeish.  Similar comments apply for refname, since there are a
variety of cases in which we won't have a ref.

This commit wires up the code to print this information, but doesn't
pass any of it at this point.  In a future commit, we'll have various
code paths pass the actual useful data down.

Signed-off-by: brian m. carlson <bk2204@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-16 11:37:02 -07:00
Junio C Hamano
d1075adfdf Merge branch 'en/merge-path-collision'
Handling of conflicting renames in merge-recursive have further
been made consistent with how existing codepaths try to mimic what
is done to add/add conflicts.

* en/merge-path-collision:
  merge-recursive: apply collision handling unification to recursive case
2020-03-09 11:21:20 -07:00
Junio C Hamano
48d5f25ddd Merge branch 'en/t3433-rebase-stat-dirty-failure'
The merge-recursive machinery failed to refresh the cache entry for
a merge result in a couple of places, resulting in an unnecessary
merge failure, which has been fixed.

* en/t3433-rebase-stat-dirty-failure:
  merge-recursive: fix the refresh logic in update_file_flags
  t3433: new rebase testcase documenting a stat-dirty-like failure
2020-03-02 15:07:19 -08:00
Elijah Newren
802050400a merge-recursive: apply collision handling unification to recursive case
In the en/merge-path-collision topic (see commit ac193e0e0a, "Merge
branch 'en/merge-path-collision'", 2019-01-04), all the "file collision"
conflict types were modified for consistency.  In particular,
rename/add, rename/rename(2to1) and each rename/add piece of a
rename/rename(1to2)/add[/add] conflict were made to behave like add/add
conflicts have always been handled.

However, this consistency was not enforced when opt->priv->call_depth >
0 for rename/rename conflicts.  Update rename/rename(1to2) and
rename/rename(2to1) conflicts in the recursive case to also be
consistent.  As an added bonus, this simplifies the code considerably.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-27 10:59:59 -08:00
Elijah Newren
fb1c18fc46 merge-recursive: fix the refresh logic in update_file_flags
If we need to delete a higher stage entry in the index to place the file
at stage 0, then we'll lose that file's stat information.  In such
situations we may still be able to detect that the file on disk is the
version we want (as noted by our comment in the code:
  /* do not overwrite file if already present */
), but we do still need to update the mtime since we are creating a new
cache_entry for that file.  Update the logic used to determine whether
we refresh a file's mtime.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-19 10:13:31 -08:00
Junio C Hamano
4c616c2ba1 merge-recursive: use subtraction to flip stage
The flip_stage() helper uses a bit-flipping xor to switch between "2"
and "3". While clever, this relies on a property of those two numbers
that is mostly coincidence. Let's write it as a subtraction; that's more
clear and would extend to other numbers if somebody copies the logic.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-27 11:17:41 -08:00
Jeff King
ee798742bd merge-recursive: silence -Wxor-used-as-pow warning
The merge-recursive code uses stage number constants like this:

  add = &ci->ren1->dst_entry->stages[2 ^ 1];
  ...
  add = &ci->ren2->dst_entry->stages[3 ^ 1];

The xor has the effect of flipping the "1" bit, so that "2 ^ 1" becomes
"3" and "3 ^ 1" becomes "2", which correspond to the "ours" and "theirs"
stages respectively.

Unfortunately, clang-10 and up issue a warning for this code:

  merge-recursive.c:1759:40: error: result of '2 ^ 1' is 3; did you mean '1 << 1' (2)? [-Werror,-Wxor-used-as-pow]
                  add = &ci->ren1->dst_entry->stages[2 ^ 1];
                                                     ~~^~~
                                                     1 << 1
  merge-recursive.c:1759:40: note: replace expression with '0x2 ^ 1' to silence this warning

We could silence it by using 0x2, as the compiler mentions. Or by just
using the constants "2" and "3" directly. But after digging into it, I
do think this bit-flip is telling us something. If we just wrote:

  add = &ci->ren2->dst_entry->stages[2];

for the second one, you might think that "ren2" and "2" correspond. But
they don't. The logic is: ren2 is theirs, which is stage 3, but we
are interested in the opposite side's stage, so flip it to 2.

So let's keep the bit-flipping, but let's also put it behind a named
function, which will make its purpose a bit clearer. This also has the
side effect of suppressing the warning (and an optimizing compiler
should be able to easily turn it into a constant as before).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-27 11:15:35 -08:00
Junio C Hamano
f25f04edca Merge branch 'en/merge-recursive-oid-eq-simplify'
Code cleanup.

* en/merge-recursive-oid-eq-simplify:
  merge-recursive: remove unnecessary oid_eq function
2020-01-06 14:17:51 -08:00
Elijah Newren
763a59e71c merge-recursive: remove unnecessary oid_eq function
Back when merge-recursive was first introduced in commit 6d297f8137
(Status update on merge-recursive in C, 2006-07-08), it created a
sha_eq() function.  This function pre-dated the introduction of
hashcmp() to cache.h by about a month, but was switched over to using
hashcmp() as part of commit 9047ebbc22 (Split out merge_recursive() to
merge-recursive.c, 2008-08-12).  In commit b4da9d62f9 (merge-recursive:
convert leaf functions to use struct object_id, 2016-06-24), sha_eq() was
renamed to oid_eq() and its hashcmp() call was switched to oideq().

oid_eq() is basically just a wrapper around oideq() that has some extra
checks to protect against NULL arguments or to allow short-circuiting if
one of the arguments is NULL.  I don't know if any caller ever tried to
call with NULL arguments, but certainly none do now which means the
extra checks serve no purpose.  (Also, if these checks were genuinely
useful, then they probably should be added to the main oideq() so all
callers could benefit from them.)

Reduce the cognitive overhead of having both oid_eq() and oideq(), by
getting rid of merge-recursive's special oid_eq() wrapper.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-02 10:35:24 -08:00
Junio C Hamano
d9800351d3 Merge branch 'en/merge-recursive-directory-rename-fixes'
When all files from some subdirectory were renamed to the root
directory, the directory rename heuristics would fail to detect that
as a rename/merge of the subdirectory to the root directory, which has
been corrected.

* en/merge-recursive-directory-rename-fixes:
  t604[236]: do not run setup in separate tests
  merge-recursive: fix merging a subdirectory into the root directory
  merge-recursive: clean up get_renamed_dir_portion()
2019-11-10 18:02:13 +09:00
Elijah Newren
49b8133a9e merge-recursive: fix merging a subdirectory into the root directory
We allow renaming all entries in e.g. a directory named z/ into a
directory named y/ to be detected as a z/ -> y/ rename, so that if the
other side of history adds any files to the directory z/ in the mean
time, we can provide the hint that they should be moved to y/.

There is no reason to not allow 'y/' to be the root directory, but the
code did not handle that case correctly.  Add a testcase and the
necessary special checks to support this case.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-23 11:32:49 +09:00
Elijah Newren
d3eebaad5e merge-recursive: clean up get_renamed_dir_portion()
Dscho noted a few things making this function hard to follow.
Restructure it a bit and add comments to make it easier to follow.  The
restructurings include:

  * There was a special case if-check at the end of the function
    checking whether someone just renamed a file within its original
    directory, meaning that there could be no directory rename involved.
    That check was slightly convoluted; it could be done in a more
    straightforward fashion earlier in the function, and can be done
    more cheaply too (no call to strncmp).

  * The conditions for advancing end_of_old and end_of_new before
    calling strchr were both confusing and unnecessary.  If either
    points at a '/', then they need to be advanced in order to find the
    next '/'.  If either doesn't point at a '/', then advancing them one
    char before calling strchr() doesn't hurt.  So, just rip out the
    if conditions and advance both before calling strchr().

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-23 11:32:48 +09:00
Junio C Hamano
5efabc7ed9 Merge branch 'ew/hashmap'
Code clean-up of the hashmap API, both users and implementation.

* ew/hashmap:
  hashmap_entry: remove first member requirement from docs
  hashmap: remove type arg from hashmap_{get,put,remove}_entry
  OFFSETOF_VAR macro to simplify hashmap iterators
  hashmap: introduce hashmap_free_entries
  hashmap: hashmap_{put,remove} return hashmap_entry *
  hashmap: use *_entry APIs for iteration
  hashmap_cmp_fn takes hashmap_entry params
  hashmap_get{,_from_hash} return "struct hashmap_entry *"
  hashmap: use *_entry APIs to wrap container_of
  hashmap_get_next returns "struct hashmap_entry *"
  introduce container_of macro
  hashmap_put takes "struct hashmap_entry *"
  hashmap_remove takes "const struct hashmap_entry *"
  hashmap_get takes "const struct hashmap_entry *"
  hashmap_add takes "struct hashmap_entry *"
  hashmap_get_next takes "const struct hashmap_entry *"
  hashmap_entry_init takes "struct hashmap_entry *"
  packfile: use hashmap_entry in delta_base_cache_entry
  coccicheck: detect hashmap_entry.hash assignment
  diff: use hashmap_entry_init on moved_entry.ent
2019-10-15 13:48:02 +09:00
Junio C Hamano
280bd44551 Merge branch 'en/merge-recursive-cleanup'
The merge-recursive machiery is one of the most complex parts of
the system that accumulated cruft over time.  This large series
cleans up the implementation quite a bit.

* en/merge-recursive-cleanup: (26 commits)
  merge-recursive: fix the fix to the diff3 common ancestor label
  merge-recursive: fix the diff3 common ancestor label for virtual commits
  merge-recursive: alphabetize include list
  merge-recursive: add sanity checks for relevant merge_options
  merge-recursive: rename MERGE_RECURSIVE_* to MERGE_VARIANT_*
  merge-recursive: split internal fields into a separate struct
  merge-recursive: avoid losing output and leaking memory holding that output
  merge-recursive: comment and reorder the merge_options fields
  merge-recursive: consolidate unnecessary fields in merge_options
  merge-recursive: move some definitions around to clean up the header
  merge-recursive: rename merge_options argument to opt in header
  merge-recursive: rename 'mrtree' to 'result_tree', for clarity
  merge-recursive: use common name for ancestors/common/base_list
  merge-recursive: fix some overly long lines
  cache-tree: share code between functions writing an index as a tree
  merge-recursive: don't force external callers to do our logging
  merge-recursive: remove useless parameter in merge_trees()
  merge-recursive: exit early if index != head
  Ensure index matches head before invoking merge machinery, round N
  merge-recursive: remove another implicit dependency on the_repository
  ...
2019-10-15 13:47:59 +09:00
Elijah Newren
b657047719 merge-recursive: fix the fix to the diff3 common ancestor label
In commit 8e4ec337 ("merge-recursive: fix the diff3 common ancestor
label for virtual commits", 2019-10-01), which was a fix to commit
743474cbfa ("merge-recursive: provide a better label for diff3
common ancestor", 2019-08-17), the label for the common ancestor was
changed from always being

         "merged common ancestors"

to instead be based on the number of merge bases and whether the merge
base was a real commit or a virtual one:

    >=2: "merged common ancestors"
      1, via merge_recursive_generic: "constructed merge base"
      1, otherwise: <abbreviated commit hash>
      0: "<empty tree>"

The handling for "constructed merge base" worked by allowing
opt->ancestor to be set in merge_recursive_generic(), so we paid
attention to the setting of that variable in merge_recursive_internal().
Now, for the outer merge, the code flow was simply the following:

	ancestor_name = "merged merge bases"
	loop over merge_bases: merge_recursive_internal()

The first merge base not needing recursion would determine its own
ancestor_name however necessary and thus run

	ancestor_name = $SOMETHING
	empty loop over merge_bases...
	opt->ancestor = ancestor_name
        merge_trees_internal()

Now, the next set of merge_bases that would need to be merged after this
particular merge had completed would note that opt->ancestor has been
set to something (to a local ancestor_name variable that has since been
popped off the stack), and thus it would run:

	... else if (opt->ancestor) {
		ancestor_name = opt->ancestor;  /* OOPS! */
        loop over merge_bases: merge_recursive_internal()
        opt->ancestor = ancestor_name
        merge_trees_internal()

This resulted in garbage strings being printed for the virtual merge
bases, which was visible in git.git by just merging commit b744c3af07
into commit 6d8cb22a4f.  There are two ways to fix this: set
opt->ancestor to NULL after using it to avoid re-use, or add a
!opt->priv->call_depth check to the if block for using a pre-defined
opt->ancestor.  Apply both fixes.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-08 11:36:27 +09:00
Eric Wong
404ab78e39 hashmap: remove type arg from hashmap_{get,put,remove}_entry
Since these macros already take a `keyvar' pointer of a known type,
we can rely on OFFSETOF_VAR to get the correct offset without
relying on non-portable `__typeof__' and `offsetof'.

Argument order is also rearranged, so `keyvar' and `member' are
sequential as they are used as: `keyvar->member'

Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-07 10:20:12 +09:00
Eric Wong
23dee69f53 OFFSETOF_VAR macro to simplify hashmap iterators
While we cannot rely on a `__typeof__' operator being portable
to use with `offsetof'; we can calculate the pointer offset
using an existing pointer and the address of a member using
pointer arithmetic for compilers without `__typeof__'.

This allows us to simplify usage of hashmap iterator macros
by not having to specify a type when a pointer of that type
is already given.

In the future, list iterator macros (e.g. list_for_each_entry)
may also be implemented using OFFSETOF_VAR to save hackers the
trouble of using container_of/list_entry macros and without
relying on non-portable `__typeof__'.

v3: use `__typeof__' to avoid clang warnings

Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-07 10:20:11 +09:00
Eric Wong
c8e424c9c9 hashmap: introduce hashmap_free_entries
`hashmap_free_entries' behaves like `container_of' and passes
the offset of the hashmap_entry struct to the internal
`hashmap_free_' function, allowing the function to free any
struct pointer regardless of where the hashmap_entry field
is located.

`hashmap_free' no longer takes any arguments aside from
the hashmap itself.

Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-07 10:20:11 +09:00
Eric Wong
87571c3f71 hashmap: use *_entry APIs for iteration
Inspired by list_for_each_entry in the Linux kernel.
Once again, these are somewhat compromised usability-wise
by compilers lacking __typeof__ support.

Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-07 10:20:11 +09:00
Eric Wong
939af16eac hashmap_cmp_fn takes hashmap_entry params
Another step in eliminating the requirement of hashmap_entry
being the first member of a struct.

Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-07 10:20:11 +09:00
Eric Wong
f23a465132 hashmap_get{,_from_hash} return "struct hashmap_entry *"
Update callers to use hashmap_get_entry, hashmap_get_entry_from_hash
or container_of as appropriate.

This is another step towards eliminating the requirement of
hashmap_entry being the first field in a struct.

Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-07 10:20:11 +09:00
Eric Wong
26b455f21e hashmap_put takes "struct hashmap_entry *"
This is less error-prone than "void *" as the compiler now
detects invalid types being passed.

Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-07 10:20:10 +09:00