Code simplification and test coverage enhancement.
* bc/filter-process:
t2060: add a test for switch with --orphan and --discard-changes
builtin/checkout: simplify metadata initialization
The command line completion script (in contrib/) tried to complete
"git stash -p" as if it were "git stash push -p", but it was too
aggressive and also affected "git stash show -p", which has been
corrected.
* vs/complete-stash-show-p-fix:
completion: don't override given stash subcommand with -p
The check in "git fsck" to ensure that the tree objects are sorted
still had corner cases it missed unsorted entries.
* rs/fsck-duplicate-names-in-trees:
fsck: detect more in-tree d/f conflicts
t1450: demonstrate undetected in-tree d/f conflict
t1450: increase test coverage of in-tree d/f detection
fsck: fix a typo in a comment
"git bugreport" learns to report what shell is in use.
* es/bugreport-shell:
bugreport: include user interactive shell
help: add shell-path to --build-options
As FreeBSD is not the only platform whose regexp library reports
a REG_ILLSEQ error when fed invalid UTF-8, add logic to detect that
automatically and skip the affected tests.
* cb/t4210-illseq-auto-detect:
t4210: detect REG_ILLSEQ dynamically and skip affected tests
t/helper: teach test-regex to report pattern errors (like REG_ILLSEQ)
"git log -L..." now takes advantage of the "which paths are touched
by this commit?" info stored in the commit-graph system.
* ds/line-log-on-bloom:
line-log: integrate with changed-path Bloom filters
line-log: try to use generation number-based topo-ordering
line-log: more responsive, incremental 'git log -L'
t4211-line-log: add tests for parent oids
line-log: remove unused fields from 'struct line_log_data'
While the MyFirstContribution guide exists and has received some use and
positive reviews, it is still not as discoverable as it could be. Add a
reference to it from the GitHub pull request template, where many
brand-new contributors may look. Also add a reference to it in
SubmittingPatches, which is the central source of guidance for patch
contribution.
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Reviewed-by: Philippe Blain <levraiphilippeblain@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
For each worktree removed by "git worktree prune", it reports the reason
for the removal. All reasons share the common prefix "Removing
worktrees/%s:". As new removal reasons are added, this prefix needs to
be duplicated, which is error-prone and potentially cumbersome.
Therefore, factor out the common prefix.
Although this change seems to increase the "sentence lego quotient", it
should be reasonably safe, as the reason for removal is a distinct
clause, not strictly related to the prefix. Moreover, the "worktrees" in
"Removing worktrees/%s:" is a path literal which ought not be localized,
so by factoring it out, we can more easily avoid exposing that path
fragment to translators.
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 0b4396f068 (git-p4: make python2.7 the oldest supported version,
2019-12-13), git-p4 was updated to only support 2.7 and newer. Since
Python 2.6 is pretty much ancient history, update CodingGuidelines to
show that 2.7 is the oldest version supported.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 48a8c26c62 (Documentation: avoid poor-man's small caps GIT,
2013-01-21), the documentation was amended to spell Git's name as Git
when talking about the system as a whole. However, t/README was skipped
over when the treatment was applied.
Bring t/README into conformance with the CodingGuidelines by casing
"Git" properly.
While we're at it, fix a small typo. Change "the git internal" to "the
Git internals".
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Use the provided free_commit_graph() to properly free the commit graph
in fuzz-commit-graph. Otherwise, the fuzzer itself leaks memory when the
struct contains pointers to allocated memory.
Signed-off-by: Josh Steadmon <steadmon@google.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In trace output (when GIT_TRACE_CURL is true), redact the values of all
HTTP cookies by default. Now that auth headers (since the implementation
of GIT_TRACE_CURL in 74c682d3c6 ("http.c: implement the GIT_TRACE_CURL
environment variable", 2016-05-24)) and cookie values (since this
commit) are redacted by default in these traces, also allow the user to
inhibit these redactions through an environment variable.
Since values of all cookies are now redacted by default,
GIT_REDACT_COOKIES (which previously allowed users to select individual
cookies to redact) now has no effect.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
do_match_pathspec() started life as match_pathspec_depth_1() and for
correctness was only supposed to be called from match_pathspec_depth().
match_pathspec_depth() was later renamed to match_pathspec(), so the
invariant we expect today is that do_match_pathspec() has no direct
callers outside of match_pathspec().
Unfortunately, this intention was lost with the renames of the two
functions, and additional calls to do_match_pathspec() were added in
commits 75a6315f74 ("ls-files: add pathspec matching for submodules",
2016-10-07) and 89a1f4aaf7 ("dir: if our pathspec might match files
under a dir, recurse into it", 2019-09-17). Of course,
do_match_pathspec() had an important advantge over match_pathspec() --
match_pathspec() would hardcode flags to one of two values, and these
new callers needed to pass some other value for flags. Also, although
calling do_match_pathspec() directly was incorrect, there likely wasn't
any difference in the observable end output, because the bug just meant
that fill_diretory() would recurse into unneeded directories. Since
subsequent does-this-path-match checks on individual paths under the
directory would cause those extra paths to be filtered out, the only
difference from using the wrong function was unnecessary computation.
The second of those bad calls to do_match_pathspec() was involved -- via
either direct movement or via copying+editing -- into a number of later
refactors. See commits 777b420347 ("dir: synchronize
treat_leading_path() and read_directory_recursive()", 2019-12-19),
8d92fb2927 ("dir: replace exponential algorithm with a linear one",
2020-04-01), and 95c11ecc73 ("Fix error-prone fill_directory() API; make
it only return matches", 2020-04-01). The last of those introduced the
usage of do_match_pathspec() on an individual file, and thus resulted in
individual paths being returned that shouldn't be.
The problem with calling do_match_pathspec() instead of match_pathspec()
is that any negated patterns such as ':!unwanted_path` will be ignored.
Add a new match_pathspec_with_flags() function to fulfill the needs of
specifying special flags while still correctly checking negated
patterns, add a big comment above do_match_pathspec() to prevent others
from misusing it, and correct current callers of do_match_pathspec() to
instead use either match_pathspec() or match_pathspec_with_flags().
One final note is that DO_MATCH_LEADING_PATHSPEC needs special
consideration when working with DO_MATCH_EXCLUDE. The point of
DO_MATCH_LEADING_PATHSPEC is that if we have a pathspec like
*/Makefile
and we are checking a directory path like
src/module/component
that we want to consider it a match so that we recurse into the
directory because it _might_ have a file named Makefile somewhere below.
However, when we are using an exclusion pattern, i.e. we have a pathspec
like
:(exclude)*/Makefile
we do NOT want to say that a directory path like
src/module/component
is a (negative) match. While there *might* be a file named 'Makefile'
somewhere below that directory, there could also be other files and we
cannot pre-emptively rule all the files under that directory out; we
need to recurse and then check individual files. Adjust the
DO_MATCH_LEADING_PATHSPEC logic to only get activated for positive
pathspecs.
Reported-by: John Millikin <jmillikin@stripe.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Previously, extensions were recognized regardless of repository format
version. If the user sets an undefined "extensions" value on a
repository of version 0 and that value is used by a future git version,
they might get an undesired result.
Because all extensions now also upgrade repository versions, tightening
the check would help avoid this for future extensions.
Signed-off-by: Xin Li <delphij@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The 'extensions' configuration variable gets special meaning in the new
repository version, so when enabling the extension we should upgrade the
repository to version 1.
Signed-off-by: Xin Li <delphij@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Retroactively adding a filter can be useful for existing shallow clones as
they allow users to see earlier change histories without downloading all
git objects in a regular --unshallow fetch.
Without this patch, users can make a clone partial by editing the
repository configuration to convert the remote into a promisor, like:
git config core.repositoryFormatVersion 1
git config extensions.partialClone origin
git fetch --unshallow --filter=blob:none origin
Since the hard part of making this work is already in place and such
edits can be error-prone, teach Git to perform the required configuration
change automatically instead.
Note that this change does not modify the existing git behavior which
recognizes setting extensions.partialClone without changing
repositoryFormatVersion.
Signed-off-by: Xin Li <delphij@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In version 1 of repository format, "extensions" gained special meaning
and it is safer to avoid upgrading when there are pre-existing
extensions.
Make list-objects-filter to use the helper function instead of setting
repository version directly as a prerequisite of exposing the upgrade
capability.
Signed-off-by: Xin Li <delphij@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
sparse-checkout's purpose is to update the working tree to have it
reflect a subset of the tracked files. As such, it shouldn't be
switching branches, making commits, downloading or uploading data, or
staging or unstaging changes. Other than updating the worktree, the
only thing sparse-checkout should touch is the SKIP_WORKTREE bit of the
index. In particular, this sets up a nice invariant: running
sparse-checkout will never change the status of any file in `git status`
(reflecting the fact that we only set the SKIP_WORKTREE bit if the file
is safe to delete, i.e. if the file is unmodified).
Traditionally, we did a _really_ bad job with this goal. The
predecessor to sparse-checkout involved manual editing of
.git/info/sparse-checkout and running `git read-tree -mu HEAD`. That
command would stage and unstage changes and overwrite dirty changes in
the working tree.
The initial implementation of the sparse-checkout command was no better;
it simply invoked `git read-tree -mu HEAD` as a subprocess and had the
same caveats, though this issue came up repeatedly in review comments
and workarounds for the problems were put in place before the feature
was merged[1, 2, 3, 4, 5, 6; especially see 4 & 6].
[1] https://lore.kernel.org/git/CABPp-BFT9A5n=_bx5LsjCvbogqwSjiwgr5amcjgbU1iAk4KLJg@mail.gmail.com/
[2] https://lore.kernel.org/git/CABPp-BEmwSwg4tgJg6nVG8a3Hpn_g-=ZjApZF4EiJO+qVgu4uw@mail.gmail.com/
[3] https://lore.kernel.org/git/CABPp-BFV7TA0qwZCQpHCqx9N+JifyRyuBQ-pZ_oGfe-NOgyh7A@mail.gmail.com/
[4] https://lore.kernel.org/git/CABPp-BHYCCD+Vx5fq35jH82eHc1-P53Lz_aGNpHJNcx9kg2K-A@mail.gmail.com/
[5] https://lore.kernel.org/git/CABPp-BF+JWYZfDqp2Tn4AEKVp4b0YMA=Mbz4Nz62D-gGgiduYQ@mail.gmail.com/
[6] https://lore.kernel.org/git/20191121163706.GV23183@szeder.dev/
However, these workarounds, in addition to disabling the feature in a
number of important cases, also missed one special case. I'll get back
to it later.
In the 2.27.0 cycle, the disabling of the feature was lifted by finally
replacing the internal equivalent of `git read-tree -mu HEAD` with
something that did what we wanted: the new update_sparsity() function in
unpack-trees.c that only ever updates SKIP_WORKTREE bits in the index
and updates the working tree to match. This new function handles all
the cases that were problematic for the old implementation, except that
it breaks the same special case that avoided the workarounds of the old
implementation, but broke it in a different way.
So...that brings us to the special case: a git clone performed with
--no-checkout. As per the meaning of the flag, --no-checkout does not
check out any branch, with the implication that you aren't on one and
need to switch to one after the clone. Implementationally, HEAD is
still set (so in some sense you are partially on a branch), but
* the index is "unborn" (non-existent)
* there are no files in the working tree (other than .git/)
* the next time git switch (or git checkout) is run it will run
unpack_trees with `initial_checkout` flag set to true.
It is not until you run, e.g. `git switch <somebranch>` that the index
will be written and files in the working tree populated.
With this special --no-checkout case, the traditional `read-tree -mu
HEAD` behavior would have done the equivalent of acting like checkout --
switch to the default branch (HEAD), write out an index that matches
HEAD, and update the working tree to match. This special case slipped
through the avoid-making-changes checks in the original sparse-checkout
command and thus continued there.
After update_sparsity() was introduced and used (see commit f56f31af03
("sparse-checkout: use new update_sparsity() function", 2020-03-27)),
the behavior for the --no-checkout case changed: Due to git's
auto-vivification of an empty in-memory index (see do_read_index() and
note that `must_exist` is false), and due to sparse-checkout's
update_working_directory() code to always write out the index after it
was done, we got a new bug. That made it so that sparse-checkout would
switch the repository from a clone with an "unborn" index (i.e. still
needing an initial_checkout), to one that had a recorded index with no
entries. Thus, instead of all the files appearing deleted in `git
status` being known to git as a special artifact of not yet being on a
branch, our recording of an empty index made it suddenly look to git as
though it was definitely on a branch with ALL files staged for deletion!
A subsequent checkout or switch then had to contend with the fact that
it wasn't on an initial_checkout but had a bunch of staged deletions.
Make sure that sparse-checkout changes nothing in the index other than
the SKIP_WORKTREE bit; in particular, when the index is unborn we do not
have any branch checked out so there is no sparsification or
de-sparsification work to do. Simply return from
update_working_directory() early.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 897d68e7af (Makefile: use curl-config --cflags, 2020-03-26), we
taught the build process to use `curl-config --cflags` to make sure that
it can find cURL's headers.
In the MSVC build, this is completely bogus because we're running in a
Git for Windows SDK whose `curl-config` supports the _GCC_ build.
Let's just ignore each and every `-I<path>` option where `<path>` points
to GCC/Clang specific headers.
Reported by Jeff Hostetler in
https://github.com/microsoft/git/issues/275.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Even if we strongly discourage putting credentials into the URLs passed
via the command-line, there _is_ support for that, and users _do_ do
that.
Let's scrub them before writing them to the reflog.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's move the 'pack_objects_hook' static
variable into this struct.
It is used by code common to protocol v0 and protocol v2.
While at it let's also free() it in upload_pack_data_clear().
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's move the 'allow_sideband_all' static
variable into this struct.
It is used only by protocol v2 code.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's move the 'allow_ref_in_want' static
variable into this struct.
It is used only by protocol v2 code.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's move the 'allow_filter' static variable
into this struct.
It is used by both protocol v0 and protocol v2 code.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's move the 'keepalive' static variable
into this struct.
It is used by code common to protocol v0 and protocol v2.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's pass that struct to upload_pack_config(),
so that this function can use all the fields of the struct.
This will be used in followup commits to move static variables
that are set in upload_pack_config() into 'upload_pack_data'.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's take this opportunity to change the
'multi_ack' variable, which is now part of 'upload_pack_data',
to an enum.
This will make it clear which values this variable can take.
Helped-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's move the multi_ack static variable into
this struct.
It is only used by protocol v0 code since protocol v2 assumes
certain baseline capabilities, but rolling it into
upload_pack_data and just letting v2 code ignore it as it does
now is more coherent and cleaner.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's move the filter_capability_requested
static variable into this struct.
It is only used by protocol v0 code since protocol v2 assumes
certain baseline capabilities, but rolling it into
upload_pack_data and just letting v2 code ignore it as it does
now is more coherent and cleaner.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's move the 'use_sideband' static variable
into this struct.
This variable is used by both v0 and v2 protocols.
While at it, let's update the comment near the variable
definition.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's move the 'no_done', 'daemon_mode' and
'timeout' variables into this struct.
They are only used by protocol v0 code since protocol v2 assumes
certain baseline capabilities, but rolling them into
upload_pack_data and just letting v2 code ignore them as it does
now is more coherent and cleaner.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's annotate fields from this struct to let
people know which ones are used only for protocol v0 and which
ones only for protocol v2.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we cleanup 'upload-pack.c' by using 'struct upload_pack_data'
more thoroughly, let's actually start using some bitfields of
that struct. These bitfields were introduced in 3145ea957d
("upload-pack: introduce fetch server command", 2018-03-15), but
were never used.
We could instead have just removed the following bitfields
from the struct:
unsigned use_thin_pack : 1;
unsigned use_ofs_delta : 1;
unsigned no_progress : 1;
unsigned use_include_tag : 1;
but using them makes it possible to remove a number of static
variables with the same name and purpose from 'upload-pack.c'.
This is a behavior change, as we accidentally used to let values
in those bitfields propagate from one v2 "fetch" command to
another for ssh/git/file connections (but not for http). That's
fixing a bug, but one nobody is likely to see, because it would
imply the client sending different capabilities for each request.
Helped-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The following lines were not covered in a recent line-coverage test
against Git:
builtin/commit-graph.c
5b6653e5 244) progress = start_delayed_progress(
5b6653e5 268) stop_progress(&progress);
These statements are executed when both '--stdin-commits' and
'--progress' are passed. Introduce a trio of tests that exercise various
combinations of these options to ensure that these lines are covered.
More importantly, this is exercising a (somewhat) previously-ignored
feature of '--stdin-commits', which is that it respects '--progress'.
Prior to 5b6653e523 (builtin/commit-graph.c: dereference tags in
builtin, 2020-05-13), dereferencing input from '--stdin-commits' was
done inside of commit-graph.c.
Now that an additional progress meter may be generated from outside of
commit-graph.c, add a corresponding test to make sure that it also
respects '--[no]-progress'.
The other location that generates progress meter output (from d335ce8f24
(commit-graph.c: show progress of finding reachable commits,
2020-05-13)) is already covered by any test that passes '--reachable'.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Acked-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A handful of tests in t5318 use 'test_line_count = 0 ...' to make sure
that some command does not write any output. While correct, it is more
idiomatic to use 'test_must_be_empty' instead. Switch the former
invocations to use the latter instead.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Acked-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Some repositories in the wild have commits that record nonsense
committer timezone (e.g. rails.git); "git fast-import" learned an
option to pass these nonsense timestamps intact to allow recreating
existing repositories as-is.
* en/fast-import-looser-date:
fast-import: add new --date-format=raw-permissive format
The error message from "git checkout -b foo -t bar baz" was
confusing.
* rs/checkout-b-track-error:
checkout: improve error messages for -b with extra argument
checkout: add tests for -b and --track
We've adopted a convention that any on-stack structure can be
initialized to have zero values in all fields with "= { 0 }", even
when the first field happens to be a pointer, but sparse complained
that a null pointer should be spelled NULL for a long time. Start
using -Wno-universal-initializer option to squelch it.
* lo/sparse-universal-zero-init:
sparse: allow '{ 0 }' to be used without warnings
"feature.experimental" configuration variable is to let volunteers
easily opt into a set of newer features, which use of the v2
transport protocol is now a part of.
* jn/experimental-opts-into-proto-v2:
config: let feature.experimental imply protocol.version=2
The "--prepare-p4-only" option is supposed to stop after replaying
one changeset, but kept going (by mistake?)
* bk/p4-prepare-p4-only-fix:
git-p4.py: fix --prepare-p4-only error with multiple commits
Convert submodule subcommand 'set-branch' to a builtin and call it via
'git-submodule.sh'.
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
Helped-by: Denton Liu <liu.denton@gmail.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Helped-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Shourya Shukla <shouryashukla.oo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When performing a tree-level diff against the working tree, we may find
that our index stat information is dirty, so we queue a filepair to be
examined later. If the actual content hasn't changed, we call this a
stat-unmatch; the stat information was out of date, but there's no
actual diff. Normally diffcore_std() would detect and remove these
identical filepairs via diffcore_skip_stat_unmatch(). However, when
"--quiet" is used, we want to stop the diff as soon as we see any
changes, so we check for stat-unmatches immediately in diff_change().
That check may require us to actually load the file contents into the
pair of diff_filespecs. If we find that the pair isn't a stat-unmatch,
then no big deal; we'd likely load the contents later anyway to generate
a patch, do rename detection, etc, so we want to hold on to it. But if
it is a stat-unmatch, then we have no more use for that data; the whole
point is that we're going discard the pair. However, we never free the
allocated diff_filespec data.
In most cases, keeping that data isn't a problem. We don't expect a lot
of stat-unmatch entries, and since we're using --quiet, we'd quit as
soon as we saw such a real change anyway. However, there are extreme
cases where it makes a big difference:
1. We'd generally mmap() the working tree half of the pair. And since
the OS may limit the total number of maps, we can run afoul of this
in large repositories. E.g.:
$ cd linux
$ git ls-files | wc -l
67959
$ sysctl vm.max_map_count
vm.max_map_count = 65530
$ git ls-files | xargs touch ;# everything is stat-dirty!
$ git diff --quiet
fatal: mmap failed: Cannot allocate memory
It should be unusual to have so many files stat-dirty, but it's
possible if you've just run a script like "sed -i" or similar.
After this patch, the above correctly exits with code 0.
2. Even if you don't hit mmap limits, the index half of the pair will
have been pulled from the object database into heap memory. Again
in a clone of linux.git, running:
$ git ls-files | head -n 10000 | xargs touch
$ git diff --quiet
peaks at 145MB heap before this patch, and 94MB after.
This patch solves the problem by freeing any diff_filespec data we
picked up during the "--quiet" stat-unmatch check in diff_changes.
Nobody is going to need that data later, so there's no point holding on
to it. There are a few things to note:
- we could skip queueing the pair entirely, which could in theory save
a little work. But there's not much to save, as we need a
diff_filepair to feed to diff_filespec_check_stat_unmatch() anyway.
And since we cache the result of the stat-unmatch checks, a later
call to diffcore_skip_stat_unmatch() call will quickly skip over
them. The diffcore code also counts up the number of stat-unmatched
pairs as it removes them. It's doubtful any callers would care about
that in combination with --quiet, but we'd have to reimplement the
logic here to be on the safe side. So it's not really worth the
trouble.
- I didn't write a test, because we always produce the correct output
unless we run up against system mmap limits, which are both
unportable and expensive to test against. Measuring peak heap
would be interesting, but our perf suite isn't yet capable of that.
- note that diff without "--quiet" does not suffer from the same
problem. In diffcore_skip_stat_unmatch(), we detect the stat-unmatch
entries and drop them immediately, so we're not carrying their data
around.
- you _can_ still trigger the mmap limit problem if you truly have
that many files with actual changes. But it's rather unlikely. The
stat-unmatch check avoids loading the file contents if the sizes
don't match, so you'd need a pretty trivial change in every single
file. Likewise, inexact rename detection might load the data for
many files all at once. But you'd need not just 64k changes, but
that many deletions and additions. The most likely candidate is
perhaps break-detection, which would load the data for all pairs and
keep it around for the content-level diff. But again, you'd need 64k
actually changed files in the first place.
So it's still possible to trigger this case, but it seems like "I
accidentally made all my files stat-dirty" is the most likely case
in the real world.
Reported-by: Jan Christoph Uhde <Jan@UhdeJc.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Junio C Hamano