PCRE2 bug 2642 was fixed in version 10.36. Our 95ca1f987e (grep/pcre2:
better support invalid UTF-8 haystacks, 2021-01-24) worked around it on
older versions by setting the flag PCRE2_NO_START_OPTIMIZE. 797c359978
(grep/pcre2: use compile-time PCREv2 version test, 2021-02-18) switched
it around to set the flag on 10.36 and higher instead, while it claimed
to use "the same test done at compile-time".
Switch the condition back to apply the workaround on PCRE2 versions
_before_ 10.36.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The GIT_FORCE_UNTRACKED_CACHE environment variable writes the untracked
cache more frequently than the core.untrackedCache config variable. This
is due to how read_directory() handles the creation of an untracked
cache.
Before this change, Git would not create the untracked cache extension
for an index that did not already have one. Users would need to run a
command such as 'git update-index --untracked-cache' before the index
would actually contain an untracked cache.
In particular, users noticed that the untracked cache would not appear
even with core.untrackedCache=true. Some users reported setting
GIT_FORCE_UNTRACKED_CACHE=1 in their engineering system environment to
ensure the untracked cache would be created.
The decision to not write the untracked cache without an environment
variable tracks back to fc9ecbeb9 (dir.c: don't flag the index as dirty
for changes to the untracked cache, 2018-02-05). The motivation of that
change is that writing the index is expensive, and if the untracked
cache is the only thing that needs to be written, then it is more
expensive than the benefit of the cache. However, this also means that
the untracked cache never gets populated, so the user who enabled it via
config does not actually get the extension until running 'git
update-index --untracked-cache' manually or using the environment
variable.
We have had a version of this change in the microsoft/git fork for a few
major releases now. It has been working well to get users into a good
state. Yes, that first index write is slow, but the remaining index
writes are much faster than they would be without this change.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Removal of unused code and doc.
* js/no-more-legacy-stash:
stash: stop warning about the obsolete `stash.useBuiltin` config setting
stash: remove documentation for `stash.useBuiltin`
add: remove support for `git-legacy-stash`
git-sh-setup: remove remnant bits referring to `git-legacy-stash`
"git diff --diff-filter=aR" is now parsed correctly.
* js/diff-filter-negation-fix:
diff-filter: be more careful when looking for negative bits
diff.c: move the diff filter bits definitions up a bit
docs(diff): lose incorrect claim about `diff-files --diff-filter=A`
Interaction between fetch.negotiationAlgorithm and
feature.experimental configuration variables has been corrected.
* en/fetch-negotiation-default-fix:
repo-settings: rename the traditional default fetch.negotiationAlgorithm
repo-settings: fix error handling for unknown values
repo-settings: fix checking for fetch.negotiationAlgorithm=default
The build procedure has been taught to notice older version of zlib
and enable our replacement uncompress2() automatically.
* ab/auto-detect-zlib-compress2:
compat: auto-detect if zlib has uncompress2()
A bug that made multi-pack bitmap and the object order out-of-sync,
making the .midx data corrupt, has been fixed.
* tb/midx-bitmap-corruption-fix:
pack-bitmap.c: gracefully fallback after opening pack/MIDX
midx: read `RIDX` chunk when present
t/lib-bitmap.sh: parameterize tests over reverse index source
t5326: move tests to t/lib-bitmap.sh
t5326: extract `test_rev_exists`
t5326: drop unnecessary setup
pack-revindex.c: instrument loading on-disk reverse index
midx.c: make changing the preferred pack safe
t5326: demonstrate bitmap corruption after permutation
"git log --remerge-diff" shows the difference from mechanical merge
result and the result that is actually recorded in a merge commit.
* en/remerge-diff:
diff-merges: avoid history simplifications when diffing merges
merge-ort: mark conflict/warning messages from inner merges as omittable
show, log: include conflict/warning messages in --remerge-diff headers
diff: add ability to insert additional headers for paths
merge-ort: format messages slightly different for use in headers
merge-ort: mark a few more conflict messages as omittable
merge-ort: capture and print ll-merge warnings in our preferred fashion
ll-merge: make callers responsible for showing warnings
log: clean unneeded objects during `log --remerge-diff`
show, log: provide a --remerge-diff capability
Problems identified by Coverity in the reftable code have been
corrected.
* hn/reftable-coverity-fixes:
reftable: add print functions to the record types
reftable: make reftable_record a tagged union
reftable: remove outdated file reftable.c
reftable: implement record equality generically
reftable: make reftable-record.h function signatures const correct
reftable: handle null refnames in reftable_ref_record_equal
reftable: drop stray printf in readwrite_test
reftable: order unittests by complexity
reftable: all xxx_free() functions accept NULL arguments
reftable: fix resource warning
reftable: ignore remove() return value in stack_test.c
reftable: check reftable_stack_auto_compact() return value
reftable: fix resource leak blocksource.c
reftable: fix resource leak in block.c error path
reftable: fix OOB stack write in print functions
The command line completion (in contrib/) learns to complete
arguments to give to "git sparse-checkout" command.
* ld/sparse-index-bash-completion:
completion: handle unusual characters for sparse-checkout
completion: improve sparse-checkout cone mode directory completion
completion: address sparse-checkout issues
The "struct option" added in 4a28847839 (diff.c: prepare to use
parse_options() for parsing, 2019-01-27) would be free'd in the case
of diff_setup_done() being called.
But not all codepaths that allocate it reach that,
e.g. "t6427-diff3-conflict-markers.sh" will now free memory that it
didn't free before. By using FREE_AND_NULL() here (which
diff_setup_done() also does) we ensure that we free the memory, and
that we won't have double-free's.
Before this running:
./t6427-diff3-conflict-markers.sh -vixd --run=7
Would report:
SUMMARY: LeakSanitizer: 7823 byte(s) leaked in 6 allocation(s).
But now we'll report:
SUMMARY: LeakSanitizer: 703 byte(s) leaked in 5 allocation(s).
I.e. the largest leak in that particular test has now been addressed.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Have the diff_free() function call clear_pathspec(). Since the
diff_flush() function calls this all its callers can be simplified to
rely on it instead.
When I added the diff_free() function in e900d494dc (diff: add an API
for deferred freeing, 2021-02-11) I simply missed this, or wasn't
interested in it. Let's consolidate this now. This means that any
future callers (and I've got revision.c in mind) that embed a "struct
diff_options" can simply call diff_free() instead of needing know that
it has an embedded pathspec.
This does fix a bunch of leaks, but I can't mark any test here as
passing under the SANITIZE=leak testing mode because in
886e1084d7 (builtin/: add UNLEAKs, 2017-10-01) an UNLEAK(rev) was
added, which plasters over the memory
leak. E.g. "t4011-diff-symlink.sh" would report fewer leaks with this
fix, but because of the UNLEAK() reports none.
I'll eventually loop around to removing that UNLEAK(rev) annotation as
I'll fix deeper issues with the revisions API leaking. This is one
small step on the way there, a new freeing function in revisions.c
will want to call this diff_free().
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix a memory leak in the parse_date_format() function by providing a
new date_mode_release() companion function.
By using this in "t/helper/test-date.c" we can mark the
"t0006-date.sh" test as passing when git is compiled with
SANITIZE=leak, and whitelist it to run under
"GIT_TEST_PASSING_SANITIZE_LEAK=true" by adding
"TEST_PASSES_SANITIZE_LEAK=true" to the test itself.
The other tests that expose this memory leak (i.e. take the
"mode->type == DATE_STRFTIME" branch in parse_date_format()) are
"t6300-for-each-ref.sh" and "t7004-tag.sh". The former is due to an
easily fixed leak in "ref-filter.c", and brings the failures in
"t6300-for-each-ref.sh" down from 51 to 48.
Fixing the remaining leaks will have to wait until there's a
release_revisions() in "revision.c", as they have to do with leaks via
"struct rev_info".
There is also a leak in "builtin/blame.c" due to its call to
parse_date_format() to parse the "blame.date" configuration. However
as it declares a file-level "static struct date_mode blame_date_mode"
to track the data, LSAN will not report it as a leak. It's possible to
get valgrind(1) to complain about it with e.g.:
valgrind --leak-check=full --show-leak-kinds=all ./git -P -c blame.date=format:%Y blame README.md
But let's focus on things LSAN complains about, and are thus
observable with "TEST_PASSES_SANITIZE_LEAK=true". We should get to
fixing memory leaks in "builtin/blame.c", but as doing so would
require some re-arrangement of cmd_blame() let's leave it for some
other time.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add basic API doc comments to date.h, and while doing so move the the
parse_date_format() function adjacent to show_date(). This way all the
"struct date_mode" functions are grouped together. Documenting the
rest is one of our #leftoverbits.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Provide and use a DATE_MODE_INIT macro. Most of the users of struct
date_mode" use it via pretty.h's "struct pretty_print_context" which
doesn't have an initialization macro, so we're still bound to being
initialized to "{ 0 }" by default.
But we can change the couple of callers that directly declared a
variable on the stack to instead use the initializer, and thus do away
with the "mode.local = 0" added in add00ba2de (date: make "local"
orthogonal to date format, 2015-09-03).
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move the declaration of the date.c functions from cache.h, and adjust
the relevant users to include the new date.h header.
The show_ident_date() function belonged in pretty.h (it's defined in
pretty.c), its two users outside of pretty.c didn't strictly need to
include pretty.h, as they get it indirectly, but let's add it to them
anyway.
Similarly, the change to "builtin/{fast-import,show-branch,tag}.c"
isn't needed as far as the compiler is concerned, but since they all
use the "DATE_MODE()" macro we now define in date.h, let's have them
include it.
We could simply include this new header in "cache.h", but as this
change shows these functions weren't common enough to warrant
including in it in the first place. By moving them out of cache.h
changes to this API will no longer cause a (mostly) full re-build of
the project when "make" is run.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There has never been a show_date_human() function on the "master"
branch in git.git. This declaration was added in b841d4ff43 (Add
`human` format to test-tool, 2019-01-28).
A look at the ML history reveals that it was leftover cruft from an
earlier version of that commit[1].
1. https://lore.kernel.org/git/20190118061805.19086-5-ischis2@cox.net/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Simplify the parsing of "grep.patternType" and
"grep.extendedRegexp". This changes no behavior, but gets rid of
complex parsing logic that isn't needed anymore.
When "grep.patternType" was introduced in 84befcd0a4 (grep: add a
grep.patternType configuration setting, 2012-08-03) we promised that:
1. You can set "grep.patternType", and "[setting it to] 'default'
will return to the default matching behavior".
In that context "the default" meant whatever the configuration
system specified before that change, i.e. via grep.extendedRegexp.
2. We'd support the existing "grep.extendedRegexp" option, but ignore
it when the new "grep.patternType" option is set. We said we'd
only ignore the older "grep.extendedRegexp" option "when the
`grep.patternType` option is set to a value other than
'default'".
In a preceding commit we changed grep_config() to be called after
grep_init(), which means that much of the complexity here can go
away.
As before both "grep.patternType" and "grep.extendedRegexp" are
last-one-wins variable, with "grep.extendedRegexp" yielding to
"grep.patternType", except when "grep.patternType=default".
Note that as the previously added tests indicate this cannot be done
on-the-fly as we see the config variables, without introducing more
state keeping. I.e. if we see:
-c grep.extendedRegexp=false
-c grep.patternType=default
-c extendedRegexp=true
We need to select ERE, since grep.patternType=default unselects that
variable, which normally has higher precedence, but we also need to
select BRE in cases of:
-c grep.extendedRegexp=true \
-c grep.extendedRegexp=false
Which would not be the case for this, which select ERE:
-c grep.patternType=extended \
-c grep.extendedRegexp=false
Therefore we cannot do this on-the-fly in grep_config without also
introducing tracking variables for not only the pattern type, but what
the source of that pattern type was.
So we need to decide on the pattern after our config was fully
parsed. Let's do that by deferring the decision on the pattern type
until it's time to compile it in compile_regexp().
By that time we've not only parsed the config, but also handled the
command-line options. Those will set "opt.pattern_type_option" (*not*
"opt.extended_regexp_option"!).
At that point all we need to do is see if "grep.patternType" was
UNSPECIFIED in the end (including an explicit "=default"), if so we'll
use the "grep.extendedRegexp" configuration, if any.
See my 07a3d41173 (grep: remove regflags from the public grep_opt
API, 2017-06-29) for addition of the two comments being removed here,
i.e. the complexity noted in that commit is now going away.
1. https://lore.kernel.org/git/patch-v8-09.10-c211bb0c69d-20220118T155211Z-avarab@gmail.com/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change code in compile_regexp() to check the cheaper boolean
"!opt->pcre2" condition before the "memchr()" search.
This doesn't noticeably optimize anything, but makes the code more
obvious and conventional. The line wrapping being added here also
makes a subsequent commit smaller.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the "pattern_type_option" member of "struct grep_opt" to use
the enum type we use for it.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The grep_init() function used the odd pattern of initializing the
passed-in "struct grep_opt" with a statically defined "grep_defaults"
struct, which would be modified in-place when we invoked
grep_config().
So we effectively (b) initialized config, (a) then defaults, (c)
followed by user options. Usually those are ordered as "a", "b" and
"c" instead.
As the comments being removed here show the previous behavior needed
to be carefully explained as we'd potentially share the populated
configuration among different instances of grep_init(). In practice we
didn't do that, but now that it can't be a concern anymore let's
remove those comments.
This does not change the behavior of any of the configuration
variables or options. That would have been the case if we didn't move
around the grep_config() call in "builtin/log.c". But now that we call
"grep_config" after "git_log_config" and "git_format_config" we'll
need to pass in the already initialized "struct grep_opt *".
See 6ba9bb76e0 (grep: copy struct in one fell swoop, 2020-11-29) and
7687a0541e (grep: move the configuration parsing logic to grep.[ch],
2012-10-09) for the commits that added the comments.
The memcpy() pattern here will be optimized away and follows the
convention of other *_init() functions. See 5726a6b401 (*.c *_init():
define in terms of corresponding *_INIT macro, 2021-07-01).
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change grep_cmd_config() to stop passing around the always-NULL "cb"
value. When this code was added in 7e8f59d577 (grep: color patterns
in output, 2009-03-07) it was non-NULL, but when that changed in
15fabd1bbd (builtin/grep.c: make configuration callback more
reusable, 2012-10-09) this code was left behind.
In a subsequent change I'll start using the "cb" value, this will make
it clear which functions we call need it, and which don't.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change code in "builtin/grep.c" and "builtin/ls-tree.c" to trust the
"prefix" passed from "run_builtin()". The "prefix" we get from setup.c
is either going to be NULL or a string of length >0, never "".
So we can drop the "prefix && *prefix" checks added for
"builtin/grep.c" in 0d042fecf2 (git-grep: show pathnames relative to
the current directory, 2006-08-11), and for "builtin/ls-tree.c" in
a69dd585fc (ls-tree: chomp leading directories when run from a
subdirectory, 2005-12-23).
As seen in code in revision.c that was added in cd676a5136 (diff
--relative: output paths as relative to the current subdirectory,
2008-02-12) we already have existing code that does away with this
assertion.
This makes it easier to reason about a subsequent change to the
"prefix_length" code in grep.c in a subsequent commit, and since we're
going to the trouble of doing that let's leave behind an assert() to
promise this to any future callers.
For "builtin/grep.c" it would be painful to pass the "prefix" down the
callchain of:
cmd_grep -> grep_tree -> grep_submodule -> grep_cache -> grep_oid ->
grep_source_name
So for the code that needs it in grep_source_name() let's add a
"grep_prefix" variable similar to the existing "ls_tree_prefix".
While at it let's move the code in cmd_ls_tree() around so that we
assign to the "ls_tree_prefix" right after declaring the variables,
and stop assigning to "prefix". We only subsequently used that
variable later in the function after clobbering it. Let's just use our
own "grep_prefix" instead.
Let's also add an assert() in git.c, so that we'll make this promise
about the "prefix" to any current and future callers, as well as to
any readers of the code.
Code history:
* The strlen() in "grep.c" hasn't been used since 493b7a08d8 (grep:
accept relative paths outside current working directory, 2009-09-05).
When that code was added in 0d042fecf2 (git-grep: show pathnames
relative to the current directory, 2006-08-11) we used the length.
But since 493b7a08d8 we haven't used it for anything except a
boolean check that we could have done on the "prefix" member
itself.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Extend the grep tests to assert that setting
"grep.patternType=extended" followed by "grep.patternType=default"
will behave as if "--basic-regexp" was provided, and not as
"--extended-regexp". In a subsequent commit we'll need to treat
"grep.patternType=default" as a special-case, but let's make sure we
ignore it if it's being set to "default" following an earlier
non-"default" "grep.patternType" setting.
Let's also test what happens when we have a sequence of "extended"
followed by "default" and "fixed". In that case the "fixed" should
prevail, as well as tests to check that a "grep.extendedRegexp=true"
followed by a "grep.extendedRegexp=false" behaves as though
"grep.extendedRegexp" wasn't provided.
See [1] for the source of some of these tests, and their
initial (pseudocode) implementation, and [2] for a later discussion
about a breakage due to missing testing (which had been noted in [1]
all along).
1. https://lore.kernel.org/git/xmqqv8zf6j86.fsf@gitster.g/
2. https://lore.kernel.org/git/xmqqpmoczwtu.fsf@gitster.g/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Refactor the repeated test code for finding out whether a given set of
configuration will pick basic, extended or fixed into a new
"test_pattern_type" helper function.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Extend the tests added in my 9df46763ef (log: add exhaustive tests
for pattern style options & config, 2017-05-20) to check not only
whether "git log" handles "grep.patternType", but also "git show"
etc.
It's sufficient to check whether we match a "fixed" or a "basic" regex
here to see if these codepaths correctly invoked grep_config(). We
don't need to check the details of their regular expression matching
as the "log" test does.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This "regex_t" in grep_opt has not been used since
f9b9faf6f8 (builtin-grep: allow more than one patterns., 2006-05-02),
we still use a "regex_t" for compiling regexes, but that's in the
"grep_pat" struct".
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
34ae3b70 (name-rev: deprecate --stdin in favor of --annotate-stdin,
2022-01-05) added --annotate-stdin to replace --stdin as a clearer
flag name. Since --stdin is to be deprecated, we should replace
--stdin in the output from "git name-rev -h".
Signed-off-by: John Cai <johncai86@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Stolee transitioned from Microsoft to GitHub in July 2020, but continued
to use <dstolee@microsoft.com> because it was a valid address. He also
used <stolee@gmail.com> to communicate with the mailing list since
writing plaintext emails is difficult in Outlook. However, recent issues
with GMail delaying mailing list messages created a need to change his
primary email address.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `eol` takes effect on text files only when the index has the
contents in LF line endings. Paths with contents in CRLF line
endings in the index may become dirty unless text=auto.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When "git fetch --prune" failed to prune the refs it wanted to
prune, the command issued error messages but exited with exit
status 0, which has been corrected.
* tg/fetch-prune-exit-code-fix:
fetch --prune: exit with error if pruning fails
Update the contributor-facing documents on proposed log messages.
* jc/doc-log-messages:
SubmittingPatches: explain why we care about log messages
CodingGuidelines: hint why we value clearly written log messages
SubmittingPatches: write problem statement in the log in the present tense
Pick a better random number generator and use it when we prepare
temporary filenames.
* bc/csprng-mktemps:
wrapper: use a CSPRNG to generate random file names
wrapper: add a helper to generate numbers from a CSPRNG
Doc and test update around the eol attribute.
* bc/clarify-eol-attr:
docs: correct documentation about eol attribute
t0027: add tests for eol without text in .gitattributes
The protocol keyword 'ready' isn't meant for translation. Pass it as
parameter instead of spell it in die() message (and potentially confuse
translators).
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It's useful to be able to countermand a previous --graph option, for
example if `git log --graph` is run via an alias.
Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When updating references via git-fetch(1), then by default we report to
the user which references have been changed. This output is formatted in
a nice table such that the different columns are aligned. Because the
first column contains abbreviated object IDs we thus need to iterate
over all refs which have changed and compute the minimum length for
their respective abbreviated hashes. While this effort makes sense in
most cases, it is wasteful when the user passes the `--quiet` flag: we
don't print the summary, but still compute the length.
Skip computing the summary width when the user asked for us to be quiet.
This gives us a speedup of nearly 10% when doing a mirror-fetch in a
repository with thousands of references being updated:
Benchmark 1: git fetch --quiet +refs/*:refs/* (HEAD~)
Time (mean ± σ): 96.078 s ± 0.508 s [User: 91.378 s, System: 10.870 s]
Range (min … max): 95.449 s … 96.760 s 5 runs
Benchmark 2: git fetch --quiet +refs/*:refs/* (HEAD)
Time (mean ± σ): 88.214 s ± 0.192 s [User: 83.274 s, System: 10.978 s]
Range (min … max): 87.998 s … 88.446 s 5 runs
Summary
'git fetch --quiet +refs/*:refs/* (HEAD)' ran
1.09 ± 0.01 times faster than 'git fetch --quiet +refs/*:refs/* (HEAD~)'
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
During packfile negotiation we iterate over all refs announced by the
remote side to check whether their IDs refer to commits already known to
us. If a commit is known to us already, then its date is a potential
cutoff point for commits we have in common with the remote side.
There is potentially a lot of commits announced by the remote depending
on how many refs there are in the remote repository, and for every one
of them we need to search for it in our object database and, if found,
parse the corresponding object to find out whether it is a candidate for
the cutoff date. This can be sped up by trying to look up commits via
the commit-graph first, which is a lot more efficient.
Benchmarks in a repository with about 2,1 million refs and an up-to-date
commit-graph show an almost 20% speedup when mirror-fetching:
Benchmark 1: git fetch +refs/*:refs/* (v2.35.0)
Time (mean ± σ): 115.587 s ± 2.009 s [User: 109.874 s, System: 11.305 s]
Range (min … max): 113.584 s … 118.820 s 5 runs
Benchmark 2: git fetch +refs/*:refs/* (HEAD)
Time (mean ± σ): 96.859 s ± 0.624 s [User: 91.948 s, System: 10.980 s]
Range (min … max): 96.180 s … 97.875 s 5 runs
Summary
'git fetch +refs/*:refs/* (HEAD)' ran
1.19 ± 0.02 times faster than 'git fetch +refs/*:refs/* (v2.35.0)'
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
