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62234 commits

Author SHA1 Message Date
ZheNing Hu db91988aa1 format-patch: allow a non-integral version numbers
The `-v<n>` option of `format-patch` can give nothing but an
integral iteration number to patches in a series.  Some people,
however, prefer to mark a new iteration with only a small fixup
with a non integral iteration number (e.g. an "oops, that was
wrong" fix-up patch for v4 iteration may be labeled as "v4.1").

Allow `format-patch` to take such a non-integral iteration
number.

`<n>` can be any string, such as '3.1' or '4rev2'. In the case
where it is a non-integral value, the "Range-diff" and "Interdiff"
headers will not include the previous version.

Signed-off-by: ZheNing Hu <adlternative@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-23 12:49:47 -07:00
Junio C Hamano 90917373cd Merge https://github.com/prati0100/git-gui
* https://github.com/prati0100/git-gui:
  git-gui: remove lines starting with the comment character
  git-gui: fix typo in russian locale
2021-03-01 09:22:18 -08:00
Junio C Hamano c0b27e3964 Merge branch 'js/commit-graph-warning'
* js/commit-graph-warning:
  Revert "commit-graph: when incompatible with graphs, indicate why"
2021-03-01 09:21:24 -08:00
Junio C Hamano cdc986a7c2 Revert "commit-graph: when incompatible with graphs, indicate why"
This reverts commit c85eec7fc3, as
it is a bit overzealous, we are in prerelease freeze, and we want
to have enough time to get this right and cook in 'next'.

cf. <8735xgkvuo.fsf@evledraar.gmail.com>
2021-03-01 09:19:37 -08:00
Junio C Hamano 225365fb51 Git 2.31-rc0
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-25 16:43:33 -08:00
Junio C Hamano 140045821a Merge branch 'jc/push-delete-nothing'
"git push $there --delete ''" should have been diagnosed as an
error, but instead turned into a matching push, which has been
corrected.

* jc/push-delete-nothing:
  push: do not turn --delete '' into a matching push
2021-02-25 16:43:33 -08:00
Junio C Hamano cadae717d5 Merge branch 'sh/mergetools-vimdiff1'
Mergetools update.

* sh/mergetools-vimdiff1:
  mergetools/vimdiff: add vimdiff1 merge tool variant
2021-02-25 16:43:32 -08:00
Junio C Hamano 09e72204f8 Merge branch 'dl/doc-config-camelcase'
A handful of multi-word configuration variable names in
documentation that are spelled in all lowercase have been corrected
to use the more canonical camelCase.

* dl/doc-config-camelcase:
  index-format doc: camelCase core.excludesFile
  blame-options.txt: camelcase blame.blankBoundary
  i18n.txt: camel case and monospace "i18n.commitEncoding"
2021-02-25 16:43:32 -08:00
Junio C Hamano 1c8f5dfa42 Merge branch 'js/params-vs-args'
Messages update.

* js/params-vs-args:
  replace "parameters" by "arguments" in error messages
2021-02-25 16:43:32 -08:00
Junio C Hamano d228b6b231 Merge branch 'ug/doc-commit-approxidate'
Doc update.

* ug/doc-commit-approxidate:
  doc: mention approxidates for git-commit --date
2021-02-25 16:43:32 -08:00
Junio C Hamano d166e8c1d4 Merge branch 'es/maintenance-of-bare-repositories'
The "git maintenance register" command had trouble registering bare
repositories, which had been corrected.

* es/maintenance-of-bare-repositories:
  maintenance: fix incorrect `maintenance.repo` path with bare repository
2021-02-25 16:43:32 -08:00
Junio C Hamano f277234860 Merge branch 'mt/add-chmod-fixes'
Various fixes on "git add --chmod".

* mt/add-chmod-fixes:
  add: propagate --chmod errors to exit status
  add: mark --chmod error string for translation
  add --chmod: don't update index when --dry-run is used
2021-02-25 16:43:31 -08:00
Junio C Hamano 48923e8356 Merge branch 'ds/merge-base-independent'
The code to implement "git merge-base --independent" was poorly
done and was kept from the very beginning of the feature.

* ds/merge-base-independent:
  commit-reach: stale commits may prune generation further
  commit-reach: use heuristic in remove_redundant()
  commit-reach: move compare_commits_by_gen
  commit-reach: use one walk in remove_redundant()
  commit-reach: reduce requirements for remove_redundant()
2021-02-25 16:43:31 -08:00
Junio C Hamano 682bbad64d Merge branch 'ah/rebase-no-fork-point-config'
"git rebase --[no-]fork-point" gained a configuration variable
rebase.forkPoint so that users do not have to keep specifying a
non-default setting.

* ah/rebase-no-fork-point-config:
  rebase: add a config option for --no-fork-point
2021-02-25 16:43:31 -08:00
Junio C Hamano 628c13ccee Merge branch 'mt/grep-sparse-checkout'
"git grep" has been tweaked to be limited to the sparse checkout
paths.

* mt/grep-sparse-checkout:
  grep: honor sparse-checkout on working tree searches
2021-02-25 16:43:31 -08:00
Junio C Hamano 3c8e6dda21 Merge branch 'ah/commit-graph-leakplug'
Plug a minor memory leak.

* ah/commit-graph-leakplug:
  commit-graph: avoid leaking topo_levels slab in write_commit_graph()
2021-02-25 16:43:31 -08:00
Junio C Hamano 6eea44cee1 Merge branch 'zh/difftool-skip-to'
"git difftool" learned "--skip-to=<path>" option to restart an
interrupted session from an arbitrary path.

* zh/difftool-skip-to:
  difftool.c: learn a new way start at specified file
2021-02-25 16:43:31 -08:00
Junio C Hamano ccf6861b72 Merge branch 'cw/pack-config-doc'
Doc update.

* cw/pack-config-doc:
  doc: mention bigFileThreshold for packing
2021-02-25 16:43:31 -08:00
Junio C Hamano dddb420535 Merge branch 'jc/maint-column-doc-typofix'
Doc update.

* jc/maint-column-doc-typofix:
  Documentation: typofix --column description
2021-02-25 16:43:30 -08:00
Junio C Hamano 2638e33c82 Merge branch 'ma/doc-markup-fix'
Docfix.

* ma/doc-markup-fix:
  gitmailmap.txt: fix rendering of e-mail addresses
  git.txt: fix monospace rendering
  rev-list-options.txt: fix rendering of bonus paragraph
2021-02-25 16:43:30 -08:00
Junio C Hamano 845d6030f8 Merge branch 'jc/diffcore-rotate'
"git {diff,log} --{skip,rotate}-to=<path>" allows the user to
discard diff output for early paths or move them to the end of the
output.

* jc/diffcore-rotate:
  diff: --{rotate,skip}-to=<path>
2021-02-25 16:43:30 -08:00
Junio C Hamano 3da165ca28 Merge branch 'mt/checkout-index-corner-cases'
The error codepath around the "--temp/--prefix" feature of "git
checkout-index" has been improved.

* mt/checkout-index-corner-cases:
  checkout-index: omit entries with no tempname from --temp output
  write_entry(): fix misuses of `path` in error messages
2021-02-25 16:43:30 -08:00
Junio C Hamano f47c3328ef Merge branch 'js/doc-proto-v2-response-end'
Docfix.

* js/doc-proto-v2-response-end:
  doc: fix naming of response-end-pkt
2021-02-25 16:43:30 -08:00
Junio C Hamano 18decfd11d Merge branch 'rs/blame-optim'
Optimization in "git blame"

* rs/blame-optim:
  blame: remove unnecessary use of get_commit_info()
2021-02-25 16:43:29 -08:00
Junio C Hamano d590ae5560 Merge branch 'mz/doc-notes-are-not-anchors'
Objects that lost references can be pruned away, even when they
have notes attached to it (and these notes will become dangling,
which in turn can be pruned with "git notes prune").  This has been
clarified in the documentation.

* mz/doc-notes-are-not-anchors:
  docs: clarify that refs/notes/ do not keep the attached objects alive
2021-02-25 16:43:29 -08:00
Junio C Hamano 608cc4f273 Merge branch 'ab/detox-gettext-tests'
Removal of GIT_TEST_GETTEXT_POISON continues.

* ab/detox-gettext-tests:
  tests: remove most uses of test_i18ncmp
  tests: remove last uses of C_LOCALE_OUTPUT
  tests: remove most uses of C_LOCALE_OUTPUT
  tests: remove last uses of GIT_TEST_GETTEXT_POISON=false
2021-02-25 16:43:29 -08:00
Junio C Hamano 6fe12b5215 Merge branch 'jk/rev-list-disk-usage'
"git rev-list" command learned "--disk-usage" option.

* jk/rev-list-disk-usage:
  docs/rev-list: add some examples of --disk-usage
  docs/rev-list: add an examples section
  rev-list: add --disk-usage option for calculating disk usage
  t: add --no-tag option to test_commit
2021-02-25 16:43:29 -08:00
Junio C Hamano 7dd0eaa39c index-format doc: camelCase core.excludesFile
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-24 15:21:25 -08:00
Junio C Hamano edaf10dd26 blame-options.txt: camelcase blame.blankBoundary
All other references to blame.* configuration variables are
camelCased already.  Update this one to match.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-24 15:21:25 -08:00
Denton Liu 77645b5daa i18n.txt: camel case and monospace "i18n.commitEncoding"
In 95791be750 (doc: camelCase the i18n config variables to improve
readability, 2017-07-17), the other i18n config variables were
camel cased. However, this one instance was missed.

Camel case and monospace "i18n.commitEncoding" so that it matches the
surrounding text.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
[jc: fixed 3 other mistakes that are exactly the same]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-24 15:21:25 -08:00
Matheus Tavares 9ebd7fe158 add: propagate --chmod errors to exit status
If `add` encounters an error while applying the --chmod changes, it
prints a message to stderr, but exits with a success code. This might
have been an oversight, as the command does exit with a non-zero code in
other situations where it cannot (or refuses to) update all of the
requested paths (e.g. when some of the given paths are ignored). So make
the exit behavior more consistent by also propagating --chmod errors to
the exit status.

Note: the test "all statuses changed in folder if . is given" uses paths
added by previous test cases, some of which might be symbolic links.
Because `git add --chmod` will now fail with such paths, this test would
depend on whether all the previous tests were executed, or only some
of them. Avoid that by running the test on a fresh repo with only
regular files.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-24 12:14:51 -08:00
Matheus Tavares 48960894f5 add: mark --chmod error string for translation
This error message is intended for humans, so mark it for translation.
Also use error() instead of fprintf(stderr, ...), to make the
corresponding line a bit cleaner, and to display the "error:" prefix,
which helps classifying the nature/severity of the message.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-24 12:14:51 -08:00
Matheus Tavares c937d70bfb add --chmod: don't update index when --dry-run is used
`git add --chmod` applies the mode changes even when `--dry-run` is
used. Fix that and add some tests for this option combination.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-24 12:14:51 -08:00
Alex Henrie 2803d800d2 rebase: add a config option for --no-fork-point
Some users (myself included) would prefer to have this feature off by
default because it can silently drop commits.

Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-24 11:49:10 -08:00
Junio C Hamano 20e416409f push: do not turn --delete '' into a matching push
When we added a syntax sugar "git push remote --delete <ref>" to
"git push" as a synonym to the canonical "git push remote :<ref>"
syntax at f517f1f2 (builtin-push: add --delete as syntactic sugar
for :foo, 2009-12-30), we weren't careful enough to make sure that
<ref> is not empty.

Blindly rewriting "--delete <ref>" to ":<ref>" means that an empty
string <ref> results in refspec ":", which is the syntax to ask for
"matching" push that does not delete anything.

Worse yet, if there were matching refs that can be fast-forwarded,
they would have been published prematurely, even if the user feels
that they are not ready yet to be pushed out, which would be a real
disaster.

Noticed-by: Tilman Vogel <tilman.vogel@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-23 15:19:34 -08:00
Jeff King 01168a9d89 doc: mention approxidates for git-commit --date
We describe the more strict date formats accepted by GIT_COMMITTER_DATE,
etc, but the --date option also allows the looser approxidate formats,
as well. Unfortunately we don't have a good or complete reference for
this format, but let's at least mention that it _is_ looser, and give a
few examples.

If we ever write separate, more complete date-format documentation, we
should refer to it from here.

Based-on-a-patch-by: Utku Gultopu <ugultopu@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-23 13:33:02 -08:00
Johannes Sixt b865734760 replace "parameters" by "arguments" in error messages
When an error message informs the user about an incorrect command
invocation, it should refer to "arguments", not "parameters".

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-23 13:30:45 -08:00
Seth House 30bb8088af mergetools/vimdiff: add vimdiff1 merge tool variant
This adds yet another vimdiff/gvimdiff variant and presents conflicts as
a two-way diff between 'LOCAL' and 'REMOTE'. 'MERGED' is not opened
which deviates from the norm so usage text is echoed as a Vim message on
startup that instructs the user with how to proceed and how to abort.

Vimdiff is well-suited to two-way diffs so this is an option for a more
simple, more streamlined conflict resolution. For example: it is
difficult to communicate differences across more than two files using
only syntax highlighting; default vimdiff commands to get and put
changes between buffers do not need the user to manually specify
a source or destination buffer when only using two buffers.

Like other merge tools that directly compare 'LOCAL' with 'REMOTE', this
tool will benefit when paired with the new `mergetool.hideResolved`
setting.

Signed-off-by: Seth House <seth@eseth.com>
Tested-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-23 11:37:13 -08:00
Eric Sunshine 26c7974376 maintenance: fix incorrect maintenance.repo path with bare repository
The periodic maintenance tasks configured by `git maintenance start`
invoke `git for-each-repo` to run `git maintenance run` on each path
specified by the multi-value global configuration variable
`maintenance.repo`. Because `git for-each-repo` will likely be run
outside of the repositories which require periodic maintenance, it is
mandatory that the repository paths specified by `maintenance.repo` are
absolute.

Unfortunately, however, `git maintenance register` does nothing to
ensure that the paths it assigns to `maintenance.repo` are indeed
absolute, and may in fact -- especially in the case of a bare repository
-- assign a relative path to `maintenance.repo` instead. Fix this
problem by converting all paths to absolute before assigning them to
`maintenance.repo`.

While at it, also fix `git maintenance unregister` to convert paths to
absolute, as well, in order to ensure that it can correctly remove from
`maintenance.repo` a path assigned via `git maintenance register`.

Reported-by: Clement Moyroud <clement.moyroud@gmail.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-23 00:22:45 -08:00
Junio C Hamano 966e671106 The tenth batch
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-22 16:12:43 -08:00
Junio C Hamano d68fccef86 Merge branch 'ab/test-lib'
Test framework clean-up.

* ab/test-lib:
  test-lib-functions: assert correct parameter count
  test-lib-functions: remove bug-inducing "diagnostics" helper param
  test libs: rename "diff-lib" to "lib-diff"
  t/.gitattributes: sort lines
  test-lib-functions: move function to lib-bitmap.sh
  test libs: rename gitweb-lib.sh to lib-gitweb.sh
  test libs: rename bundle helper to "lib-bundle.sh"
  test-lib-functions: remove generate_zero_bytes() wrapper
  test-lib-functions: move test_set_index_version() to its user
  test lib: change "error" to "BUG" as appropriate
  test-lib: remove check_var_migration
2021-02-22 16:12:43 -08:00
Junio C Hamano 45df6c4d75 Merge branch 'ab/diff-deferred-free'
A small memleak in "diff -I<regexp>" has been corrected.

* ab/diff-deferred-free:
  diff: plug memory leak from regcomp() on {log,diff} -I
  diff: add an API for deferred freeing
2021-02-22 16:12:43 -08:00
Junio C Hamano dcb11fc622 Merge branch 'ab/pager-exit-log'
When a pager spawned by us exited, the trace log did not record its
exit status correctly, which has been corrected.

* ab/pager-exit-log:
  pager: properly log pager exit code when signalled
  run-command: add braces for "if" block in wait_or_whine()
  pager: test for exit code with and without SIGPIPE
  pager: refactor wait_for_pager() function
2021-02-22 16:12:43 -08:00
Junio C Hamano dc24948be9 Merge branch 'ta/hash-function-transition-doc'
Update formatting and grammar of the hash transition plan
documentation, plus some updates.

* ta/hash-function-transition-doc:
  doc: use https links
  doc hash-function-transition: move rationale upwards
  doc hash-function-transition: fix incomplete sentence
  doc hash-function-transition: use upper case consistently
  doc hash-function-transition: use SHA-1 and SHA-256 consistently
  doc hash-function-transition: fix asciidoc output
2021-02-22 16:12:43 -08:00
Junio C Hamano 15af6e6fee Merge branch 'bc/signed-objects-with-both-hashes'
Signed commits and tags now allow verification of objects, whose
two object names (one in SHA-1, the other in SHA-256) are both
signed.

* bc/signed-objects-with-both-hashes:
  gpg-interface: remove other signature headers before verifying
  ref-filter: hoist signature parsing
  commit: allow parsing arbitrary buffers with headers
  gpg-interface: improve interface for parsing tags
  commit: ignore additional signatures when parsing signed commits
  ref-filter: switch some uses of unsigned long to size_t
2021-02-22 16:12:42 -08:00
Junio C Hamano b9554c03a0 Merge branch 'dl/stash-cleanup'
Documentation, code and test clean-up around "git stash".

* dl/stash-cleanup:
  stash: declare ref_stash as an array
  t3905: use test_cmp() to check file contents
  t3905: replace test -s with test_file_not_empty
  t3905: remove nested git in command substitution
  t3905: move all commands into test cases
  t3905: remove spaces after redirect operators
  git-stash.txt: be explicit about subcommand options
2021-02-22 16:12:42 -08:00
Andrzej Hunt bf4bb9f9f5 commit-graph: avoid leaking topo_levels slab in write_commit_graph()
write_commit_graph initialises topo_levels using init_topo_level_slab(),
next it calls compute_topological_levels() which can cause the slab to
grow, we therefore need to clear the slab again using
clear_topo_level_slab() when we're done.

First introduced in 72a2bfca (commit-graph: add a slab to store
topological levels, 2021-01-16).

LeakSanitizer output:

==1026==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 8 byte(s) in 1 object(s) allocated from:
    #0 0x498ae9 in realloc /src/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
    #1 0xafbed8 in xrealloc /src/git/wrapper.c:126:8
    #2 0x7966d1 in topo_level_slab_at_peek /src/git/commit-graph.c:71:1
    #3 0x7965e0 in topo_level_slab_at /src/git/commit-graph.c:71:1
    #4 0x78fbf5 in compute_topological_levels /src/git/commit-graph.c:1472:12
    #5 0x78c5c3 in write_commit_graph /src/git/commit-graph.c:2456:2
    #6 0x535c5f in graph_write /src/git/builtin/commit-graph.c:299:6
    #7 0x5350ca in cmd_commit_graph /src/git/builtin/commit-graph.c:337:11
    #8 0x4cddb1 in run_builtin /src/git/git.c:453:11
    #9 0x4cabe2 in handle_builtin /src/git/git.c:704:3
    #10 0x4cd084 in run_argv /src/git/git.c:771:4
    #11 0x4ca424 in cmd_main /src/git/git.c:902:19
    #12 0x707fb6 in main /src/git/common-main.c:52:11
    #13 0x7fee4249383f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f)

Indirect leak of 524256 byte(s) in 1 object(s) allocated from:
    #0 0x498942 in calloc /src/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
    #1 0xafc088 in xcalloc /src/git/wrapper.c:140:8
    #2 0x796870 in topo_level_slab_at_peek /src/git/commit-graph.c:71:1
    #3 0x7965e0 in topo_level_slab_at /src/git/commit-graph.c:71:1
    #4 0x78fbf5 in compute_topological_levels /src/git/commit-graph.c:1472:12
    #5 0x78c5c3 in write_commit_graph /src/git/commit-graph.c:2456:2
    #6 0x535c5f in graph_write /src/git/builtin/commit-graph.c:299:6
    #7 0x5350ca in cmd_commit_graph /src/git/builtin/commit-graph.c:337:11
    #8 0x4cddb1 in run_builtin /src/git/git.c:453:11
    #9 0x4cabe2 in handle_builtin /src/git/git.c:704:3
    #10 0x4cd084 in run_argv /src/git/git.c:771:4
    #11 0x4ca424 in cmd_main /src/git/git.c:902:19
    #12 0x707fb6 in main /src/git/common-main.c:52:11
    #13 0x7fee4249383f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f)

SUMMARY: AddressSanitizer: 524264 byte(s) leaked in 2 allocation(s).

Signed-off-by: Andrzej Hunt <ajrhunt@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-22 13:45:01 -08:00
ZheNing Hu 1c881026a1 difftool.c: learn a new way start at specified file
`git difftool` only allow us to select file to view in turn.
If there is a commit with many files and we exit in the middle,
we will have to traverse list again to get the file diff which
we want to see. Therefore,teach the command an option
`--skip-to=<path>` to allow the user to say that diffs for earlier
paths are not interesting (because they were already seen in an
earlier session) and start this session with the named path.

Signed-off-by: ZheNing Hu <adlternative@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-22 13:35:49 -08:00
Derrick Stolee 41f3c9949f commit-reach: stale commits may prune generation further
The remove_redundant_with_gen() algorithm performs a depth-first-search
to find commits in the 'array' list, starting at the parents of each
commit in 'array'. The result is that commits in 'array' are marked
STALE when they are reachable from another commit in 'array'.

This depth-first-search is fast when commits lie on or near the
first-parent history of the higher commits. The search terminates early
if all but one commit becomes marked STALE.

However, it is possible that there are two independent commits with high
generation number. In that case, the depth-first-search might languish
by searching in lower generations due to the fixed min_generation used
throughout the method.

With the expectation that commits with lower generation are expected to
become STALE more often, we can optimize further by increasing that
min_generation boundary upon discovery of the commit with minimum
generation.

We must first sort the commits in 'array' by generation. We cannot sort
'array' itself since it must preserve relative order among the returned
results (see revision.c:mark_redundant_parents() for an example).

This simplifies the initialization of min_generation, but it also allows
us to increase the new min_generation when we find the commit with
smallest generation remaining.

This requires more than two commits in order to test, so I used the
Linux kernel repository with a few commits that are slightly off of the
first-parent history. I timed the following command:

  git merge-base --independent 2ecedd756908 d2360a398f0b \
	1253935ad801 160bab43419e 0e2209629fec 1d0e16ac1a9e

The first two commits have similar generation and are near the v5.10
tag. Commit 160bab43419e is off of the first-parent history behind v5.5,
while the others are scattered somewhere reachable from v5.9. This is
designed to demonstrate the optimization, as that commit within v5.5
would normally cause a lot of extra commit walking.

Since remove_redundant_with_alg() is called only when at least one of
the input commits has a finite generation number, this algorithm is
tested with a commit-graph generated starting at a number of different
tags, the earliest being v5.5.

commit-graph at v5.5:

 | Method                | Time  |
 |-----------------------+-------|
 | *_no_gen()            | 864ms |
 | *_with_gen() (before) | 858ms |
 | *_with_gen() (after)  | 810ms |

commit-graph at v5.7:

 | Method                | Time  |
 |-----------------------+-------|
 | *_no_gen()            | 625ms |
 | *_with_gen() (before) | 572ms |
 | *_with_gen() (after)  | 517ms |

commit-graph at v5.9:

 | Method                | Time  |
 |-----------------------+-------|
 | *_no_gen()            | 268ms |
 | *_with_gen() (before) | 224ms |
 | *_with_gen() (after)  | 202ms |

commit-graph at v5.10:

 | Method                | Time  |
 |-----------------------+-------|
 | *_no_gen()            |  72ms |
 | *_with_gen() (before) |  37ms |
 | *_with_gen() (after)  |   9ms |

Note that these are only modest improvements for the case where the two
independent commits are not in the commit-graph (not until v5.10). All
algorithms get faster as more commits are indexed, which is not a
surprise. However, the cost of walking extra commits is more and more
prevalent in relative terms as more commits are indexed. Finally, the
last case allows us to jump to the minimum generation between the last
two commits (that are actually independent) so we greatly reduce the
cost in that case.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-22 13:34:34 -08:00
Derrick Stolee 3677773371 commit-reach: use heuristic in remove_redundant()
Reachability algorithms in commit-reach.c frequently benefit from using
the first-parent history as a heuristic for satisfying reachability
queries. The most obvious example was implemented in 4fbcca4e
(commit-reach: make can_all_from_reach... linear, 2018-07-20).

Update the walk in remove_redundant() to use this same heuristic. Here,
we are walking starting at the parents of the input commits. Sort those
parents and walk from the highest generation to lower. Each time, use
the heuristic of searching the first parent history before continuing to
expand the walk.

The order in which we explore the commits matters, so update
compare_commits_by_gen to break generation number ties with commit date.
This has no effect when the commits are in a commit-graph file with
corrected commit dates computed, but it will assist when the commits are
in the region "above" the commit-graph with "infinite" generation
number. Note that we cannot shift to use
compare_commits_by_gen_then_commit_date as the method prototype is
different. We use compare_commits_by_gen for QSORT() as opposed to as a
priority function.

The important piece is to ensure we short-circuit the walk when we find
that there is a single non-redundant commit. This happens frequently
when looking for merge-bases or comparing several tags with 'git
merge-base --independent'. Use a new count 'count_still_independent' and
if that hits 1 we can stop walking.

To update 'count_still_independent' properly, we add use of the RESULT
flag on the input commits. Then we can detect when we reach one of these
commits and decrease the count. We need to remove the RESULT flag at
that moment because we might re-visit that commit when popping the
stack.

We use the STALE flag to mark parents that have been added to the new
walk_start list, but we need to clear that flag before we start walking
so those flags don't halt our depth-first-search walk.

On my copy of the Linux kernel repository, the performance of 'git
merge-base --independent <all-tags>' goes from 1.1 seconds to 0.11
seconds.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-22 13:34:34 -08:00