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stat-unmatch; the stat information was out of date, but there's no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>
This test runs a function which itself runs several assertions. The
last of these assertions cleans up the .git/rebase-apply directory,
since when run with EXPENSIVE set, the function is invoked a second time
to run the same tests with a larger data set.
However, as of 2ac0d6273f ("rebase: change the default backend from "am"
to "merge"", 2020-02-15), the default backend of rebase has changed, and
cleaning up the rebase-apply directory has no effect: it no longer
exists, since we're using rebase-merge instead.
Since we don't really care which rebase backend is in use, let's just
use the command "git rebase --quit", which will do the right thing
regardless.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* 'master' of https://github.com/prati0100/git-gui:
git-gui: create a new namespace for chord script evaluation
git-gui: reduce Tcl version requirement from 8.6 to 8.5
git-gui--askpass: coerce answers to UTF-8 on Windows
git-gui: fix error popup when doing blame -> "Show History Context"
git-gui: add missing close bracket
git-gui: update German translation
git-gui: extend translation glossary template with more terms
git-gui: update pot template and German translation to current source code
Reduce the Tcl version requirement to 8.5 to allow git-gui to run on
MacOS distributions like High Sierra. While here, fix a potential
variable name collision.
* py/remove-tcloo:
git-gui: create a new namespace for chord script evaluation
git-gui: reduce Tcl version requirement from 8.6 to 8.5
Updates to the CI settings.
* js/ci-windows-update:
Azure Pipeline: switch to the latest agent pools
ci: prevent `perforce` from being quarantined
t/lib-httpd: avoid using macOS' sed
Both "git ls-remote -h" and "git grep -h" give short usage help,
like any other Git subcommand, but it is not unreasonable to expect
that the former would behave the same as "git ls-remote --head"
(there is no other sensible behaviour for the latter). The
documentation has been updated in an attempt to clarify this.
* jc/doc-single-h-is-for-help:
Documentation: clarify that `-h` alone stands for `help`
"git show" and others gave an object name in raw format in its
error output, which has been corrected to give it in hex.
* hd/show-one-mergetag-fix:
show_one_mergetag: print non-parent in hex form.
"git merge signed-tag" while lacking the public key started to say
"No signature", which was utterly wrong. This regression has been
reverted.
* hi/gpg-use-check-signature:
Revert "gpg-interface: prefer check_signature() for GPG verification"
Fix for a bug revealed by a recent change to make the protocol v2
the default.
* ds/partial-clone-fixes:
partial-clone: avoid fetching when looking for objects
partial-clone: demonstrate bugs in partial fetch
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
"git check-ignore" did not work when the given path is explicitly
marked as not ignored with a negative entry in the .gitignore file.
* en/check-ignore:
check-ignore: fix documentation and implementation to match
The code to automatically shrink the fan-out in the notes tree had
an off-by-one bug, which has been killed.
* jh/notes-fanout-fix:
notes.c: fix off-by-one error when decreasing notes fanout
t3305: check notes fanout more carefully and robustly
The index-pack code now diagnoses a bad input packstream that
records the same object twice when it is used as delta base; the
code used to declare a software bug when encountering such an
input, but it is an input error.
* jk/index-pack-dupfix:
index-pack: downgrade twice-resolved REF_DELTA to die()
"git rebase -i" identifies existing commits in its todo file with
their abbreviated object name, which could become ambigous as it
goes to create new commits, and has a mechanism to avoid ambiguity
in the main part of its execution. A few other cases however were
not covered by the protection against ambiguity, which has been
corrected.
* js/rebase-i-with-colliding-hash:
rebase -i: also avoid SHA-1 collisions with missingCommitsCheck
rebase -i: re-fix short SHA-1 collision
parse_insn_line(): improve error message when parsing failed
Running "git rm" on a submodule failed unnecessarily when
.gitmodules is only cache-dirty, which has been corrected.
* dt/submodule-rm-with-stale-cache:
git rm submodule: succeed if .gitmodules index stat info is zero
The "--recurse-submodules" option of various subcommands did not
work well when run in an alternate worktree, which has been
corrected.
* pb/recurse-submodule-in-worktree-fix:
submodule.c: use get_git_dir() instead of get_git_common_dir()
t2405: clarify test descriptions and simplify test
t2405: use git -C and test_commit -C instead of subshells
t7410: rename to t2405-worktree-submodule.sh
An earlier update to show the location of working tree in the error
message did not consider the possibility that a git command may be
run in a bare repository, which has been corrected.
* es/outside-repo-errmsg-hints:
prefix_path: show gitdir if worktree unavailable
prefix_path: show gitdir when arg is outside repo
Minor bugfixes to "git add -i" that has recently been rewritten in C.
* js/builtin-add-i-cmds:
built-in add -i: accept open-ended ranges again
built-in add -i: do not try to `patch`/`diff` an empty list of files
Evaluating the script in the same namespace as the chord itself creates
potential for variable name collision. And in that case the script would
unknowingly use the chord's variables.
For example, say the script has a variable called 'is_completed', which
also exists in the chord's namespace. The script then calls 'eval' and
sets 'is_completed' to 1 thinking it is setting its own variable,
completely unaware of how the chord works behind the scenes. This leads
to the chord never actually executing because it sees 'is_completed' as
true and thinks it has already completed.
Avoid the potential collision by creating a separate namespace for the
script that is a child of the chord's namespace.
Signed-off-by: Pratyush Yadav <me@yadavpratyush.com>
On some MacOS distributions like High Sierra, Tcl 8.5 is shipped by
default. This makes git-gui error out at startup because of the version
mismatch.
The only part that requires Tcl 8.6 is SimpleChord, which depends on
TclOO. So, don't use it and use our homegrown class.tcl instead.
This means some slight syntax changes. Since class.tcl doesn't have an
"unknown" method like TclOO does, we can't just call '$note', but have
to use '$note activate' instead. The constructor now needs a proper
namespace qualifier. Update the documentation to reflect the new syntax.
As of now, the only part of git-gui that needs Tcl 8.5 is a call to
'apply' in lib/index.tcl::lambda. Keep using it until someone shows up
shouting that their OS ships with 8.4 only. Then we would have to look
into implementing it in pure Tcl.
Signed-off-by: Pratyush Yadav <me@yadavpratyush.com>
An earlier update to show the location of working tree in the error
message did not consider the possibility that a git command may be
run in a bare repository, which has been corrected.
* es/outside-repo-errmsg-hints:
prefix_path: show gitdir if worktree unavailable
- context should be translated to ngữ cảnh instead of nội dung
- add missing accents
- switch adjective and secondary objects position:
* The formatted English text will be "To remove '+/-' lines",
it should be translated to "Để bỏ dòng bắt đầu với '+/-'
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
