Commit Graph

12350 Commits

Author SHA1 Message Date
Johannes Schindelin
e659332469 Merge branch 'unhidden-git'
It has been reported that core.hideDotFiles=false stopped working...
This topic branch fixes it.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:36:53 +02:00
Johannes Schindelin
1b01f7fbb5 Merge branch 'status-no-lock-index'
This branch allows third-party tools to call `git status
--no-lock-index` to avoid lock contention with the interactive Git usage
of the actual human user.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:36:51 +02:00
Johannes Schindelin
f31a862400 Merge pull request #797 from glhez/master
`git bundle create <bundle>` leaks handle the revlist is empty.
2017-07-26 00:36:49 +02:00
Johannes Schindelin
4542e3ba2b mingw: respect core.hidedotfiles = false in git-init again
This is a brown paper bag. When adding the tests, we actually failed
to verify that the config variable is heeded in git-init at all. And
when changing the original patch that marked the .git/ directory as
hidden after reading the config, it was lost on this developer that
the new code would use the hide_dotfiles variable before the config
was read.

The fix is obvious: read the (limited, pre-init) config *before*
creating the .git/ directory.

This fixes https://github.com/git-for-windows/git/issues/789

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:36:38 +02:00
Johannes Schindelin
e2d24af76c status: offer *not* to lock the index and update it
When a third-party tool periodically runs `git status` in order to keep
track of the state of the working tree, it is a bad idea to lock the
index: it might interfere with interactive commands executed by the
user, e.g. when the user wants to commit files.

Let's introduce the option `--no-lock-index` to prevent such problems.
The idea is that the third-party tool calls `git status` with this
option, preventing it from ever updating the index.

The downside is that the periodic `git status` calls will be a little
bit more wasteful because they may have to refresh the index repeatedly,
only to throw away the updates when it exits. This cannot really be
helped, though, as tools wanting to get a periodic update of the status
have no way to predict when the user may want to lock the index herself.

Note that the regression test added in this commit does not *really*
verify that no index.lock file was written; that test is not possible in
a portable way. Instead, we verify that .git/index is rewritten *only*
when `git status` is run without `--no-lock-index`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:36:36 +02:00
Gaël Lhez
20a1d76d36 git bundle create <bundle> leaks handle the revlist is empty.
issue #790: git bundle create does not close handle to *.lock file

This problem happens when an user tries to create an empty bundle, using the
following command:  `git bundle create <bundle> <revlist>` and when <revlist>
resolve to an empty list (for example, like `master..master`), `git bundle` fails
and warn the user about how it don't want to create empty bundle.

In that case, git tries to delete the `<bundle>.lock` file, and since there's still
an open file handle, fails to do so and ask the user if it should retry (which will
fail again).

The lock can still be deleted manually by the user (and it is required if the user
want to create a bundle after revising his rev-list).

Signed-off-by: Gaël Lhez <gael.lhez@gmail.com>
2017-07-26 00:36:35 +02:00
Johannes Schindelin
2372b0253d Merge branch 'clean-long-paths'
This addresses https://github.com/git-for-windows/git/issues/521

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:36:29 +02:00
Johannes Schindelin
d8c8e33171 Merge pull request #773 from jeffhostetler/vs2015
Build with VS2015
2017-07-26 00:36:24 +02:00
Johannes Schindelin
1eb58962f8 Merge pull request #305 from dscho/msysgit_issues_182
Allow `add -p` and `add -i` with a large number of files
2017-07-26 00:36:22 +02:00
Johannes Schindelin
d873de28b9 Merge 'remote-hg-prerequisites' into HEAD
These fixes were necessary for Sverre Rabbelier's remote-hg to work,
but for some magic reason they are not necessary for the current
remote-hg. Makes you wonder how that one gets away with it.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:36:10 +02:00
Johannes Schindelin
82a053ada6 Merge 'win-tests-fixes' into HEAD 2017-07-26 00:36:08 +02:00
Johannes Schindelin
1090e19411 Merge 'msys2' into HEAD
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:36:06 +02:00
Johannes Schindelin
1339fe3b77 Merge 'jberezanski/wincred-sso-r2' into HEAD 2017-07-26 00:36:02 +02:00
Johannes Schindelin
f56006359b t7300: git clean -dfx must show an error with long paths
In particular on Windows, where the default maximum path length is quite
small, but there are ways to circumvent that limit in many cases, it is
very important that users be given an indication why their command
failed because of too long paths when it did.

This test case makes sure that a warning is issued that would have
helped the user who reported Git for Windows' issue 521:

	https://github.com/git-for-windows/git/issues/521

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:35:52 +02:00
Johannes Schindelin
c786076faf t7800: fix quoting
When passing a command-line to call an external diff command to the
difftool, we must be prepared for paths containing special characters,
e.g. backslashes in the temporary directory's path on Windows.

This has been caught by running the test suite with an MSVC-built Git:
in contrast to the MINGW one, it does not rewrite `$TMP` to use forward
slashes instead of backslashes.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:35:51 +02:00
Johannes Schindelin
398c513928 t3701: verify that we can add *lots* of files interactively
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:35:48 +02:00
Johannes Schindelin
85af0fc813 Merge branch 'redirect-std-handles'
This topic branch introduces a highly-experimental feature allowing to
override stdin/stdout/stderr by setting environment variables e.g. to
named pipes, solving a problem in highly multi-threaded applications
where inheritable handles could cause blocked Git operations.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:35:48 +02:00
Sverre Rabbelier
4801fe6634 remote-helper: check helper status after import/export
Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Sverre Rabbelier <srabbelier@gmail.com>
2017-07-26 00:35:42 +02:00
Sverre Rabbelier
c613c03efe t9350: point out that refs are not updated correctly
This happens only when the corresponding commits are not exported in
the current fast-export run. This can happen either when the relevant
commit is already marked, or when the commit is explicitly marked
as UNINTERESTING with a negative ref by another argument.

This breaks fast-export basec remote helpers.

Signed-off-by: Sverre Rabbelier <srabbelier@gmail.com>
2017-07-26 00:35:42 +02:00
Johannes Schindelin
253923e888 t0302: add forgotten quotes
This was probably missed because nobody had a left-over `trash/`
directory and the `-f` flag made sure that no error message was
produced when the file was not found that *actually* wanted to
be removed.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:35:41 +02:00
Johannes Schindelin
ecc7723b7d Skip t9020 with MSys2
POSIX-to-Windows path mangling would make it fail.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:35:41 +02:00
Thomas Braun
53cdb44171 t0027: Disable test on MINGW
We can't mmap 2GB of RAM on our 32bit platform, so
just disable the test.

Signed-off-by: Thomas Braun <thomas.braun@byte-physics.de>
2017-07-26 00:35:41 +02:00
Johannes Schindelin
022a6b8526 Tests: optionally skip redirecting stdin/stdout/stderr
There is a really useful debugging technique developed by Sverre
Rabbelier that inserts "bash &&" somewhere in the test scripts, letting
the developer interact at given points with the current state.

Another debugging technique, used a lot by this here coder, is to run
certain executables via gdb by guarding a "gdb -args" call in
bin-wrappers/git.

Both techniques were disabled by 781f76b1(test-lib: redirect stdin of
tests).

Let's reinstate the ability to run an interactive shell by making the
redirection optional: setting the TEST_NO_REDIRECT environment variable
will skip the redirection.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:35:40 +02:00
Karsten Blees
581ff405e6 Win32: support long paths
Windows paths are typically limited to MAX_PATH = 260 characters, even
though the underlying NTFS file system supports paths up to 32,767 chars.
This limitation is also evident in Windows Explorer, cmd.exe and many
other applications (including IDEs).

Particularly annoying is that most Windows APIs return bogus error codes
if a relative path only barely exceeds MAX_PATH in conjunction with the
current directory, e.g. ERROR_PATH_NOT_FOUND / ENOENT instead of the
infinitely more helpful ERROR_FILENAME_EXCED_RANGE / ENAMETOOLONG.

Many Windows wide char APIs support longer than MAX_PATH paths through the
file namespace prefix ('\\?\' or '\\?\UNC\') followed by an absolute path.
Notable exceptions include functions dealing with executables and the
current directory (CreateProcess, LoadLibrary, Get/SetCurrentDirectory) as
well as the entire shell API (ShellExecute, SHGetSpecialFolderPath...).

Introduce a handle_long_path function to check the length of a specified
path properly (and fail with ENAMETOOLONG), and to optionally expand long
paths using the '\\?\' file namespace prefix. Short paths will not be
modified, so we don't need to worry about device names (NUL, CON, AUX).

Contrary to MSDN docs, the GetFullPathNameW function doesn't seem to be
limited to MAX_PATH (at least not on Win7), so we can use it to do the
heavy lifting of the conversion (translate '/' to '\', eliminate '.' and
'..', and make an absolute path).

Add long path error checking to xutftowcs_path for APIs with hard MAX_PATH
limit.

Add a new MAX_LONG_PATH constant and xutftowcs_long_path function for APIs
that support long paths.

While improved error checking is always active, long paths support must be
explicitly enabled via 'core.longpaths' option. This is to prevent end
users to shoot themselves in the foot by checking out files that Windows
Explorer, cmd/bash or their favorite IDE cannot handle.

Test suite:
Test the case is when the full pathname length of a dir is close
to 260 (MAX_PATH).
Bug report and an original reproducer by Andrey Rogozhnikov:
https://github.com/msysgit/git/pull/122#issuecomment-43604199

Note that the test cannot rely on the presence of short names, as they
are not enabled by default except on the system drive.

[jes: adjusted test number to avoid conflicts, reinstated && chain,
adjusted test to work without short names]

Thanks-to: Martin W. Kirst <maki@bitkings.de>
Thanks-to: Doug Kelly <dougk.ff7@gmail.com>
Signed-off-by: Karsten Blees <blees@dcon.de>
Original-test-by: Andrey Rogozhnikov <rogozhnikov.andrey@gmail.com>
Signed-off-by: Stepan Kasal <kasal@ucw.cz>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:35:34 +02:00
Johannes Schindelin
e083388278 Win32: support long paths
Windows paths are typically limited to MAX_PATH = 260 characters, even
though the underlying NTFS file system supports paths up to 32,767 chars.
This limitation is also evident in Windows Explorer, cmd.exe and many
other applications (including IDEs).

Particularly annoying is that most Windows APIs return bogus error codes
if a relative path only barely exceeds MAX_PATH in conjunction with the
current directory, e.g. ERROR_PATH_NOT_FOUND / ENOENT instead of the
infinitely more helpful ERROR_FILENAME_EXCED_RANGE / ENAMETOOLONG.

Many Windows wide char APIs support longer than MAX_PATH paths through the
file namespace prefix ('\\?\' or '\\?\UNC\') followed by an absolute path.
Notable exceptions include functions dealing with executables and the
current directory (CreateProcess, LoadLibrary, Get/SetCurrentDirectory) as
well as the entire shell API (ShellExecute, SHGetSpecialFolderPath...).

Introduce a handle_long_path function to check the length of a specified
path properly (and fail with ENAMETOOLONG), and to optionally expand long
paths using the '\\?\' file namespace prefix. Short paths will not be
modified, so we don't need to worry about device names (NUL, CON, AUX).

Contrary to MSDN docs, the GetFullPathNameW function doesn't seem to be
limited to MAX_PATH (at least not on Win7), so we can use it to do the
heavy lifting of the conversion (translate '/' to '\', eliminate '.' and
'..', and make an absolute path).

Add long path error checking to xutftowcs_path for APIs with hard MAX_PATH
limit.

Add a new MAX_LONG_PATH constant and xutftowcs_long_path function for APIs
that support long paths.

While improved error checking is always active, long paths support must be
explicitly enabled via 'core.longpaths' option. This is to prevent end
users to shoot themselves in the foot by checking out files that Windows
Explorer, cmd/bash or their favorite IDE cannot handle.

Test suite:
Test the case is when the full pathname length of a dir is close
to 260 (MAX_PATH).
Bug report and an original reproducer by Andrey Rogozhnikov:
https://github.com/msysgit/git/pull/122#issuecomment-43604199

[jes: adjusted test number to avoid conflicts]

Thanks-to: Martin W. Kirst <maki@bitkings.de>
Thanks-to: Doug Kelly <dougk.ff7@gmail.com>
Signed-off-by: Karsten Blees <blees@dcon.de>
Original-test-by: Andrey Rogozhnikov <rogozhnikov.andrey@gmail.com>
Signed-off-by: Stepan Kasal <kasal@ucw.cz>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:35:34 +02:00
Doug Kelly
882191292a Add a test demonstrating a problem with long submodule paths
[jes: adusted test number to avoid conflicts, fixed non-portable use of
the 'export' statement]

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:35:34 +02:00
Johannes Schindelin
f61640646e mingw: unset PERL5LIB by default
Git for Windows ships with its own Perl interpreter, and insists on
using it, so it will most likely wreak havoc if PERL5LIB is set before
launching Git.

Let's just unset that environment variables when spawning processes.

To make this feature extensible (and overrideable), there is a new
config setting `core.unsetenvvars` that allows specifying a
comma-separated list of names to unset before spawning processes.

Reported by Gabriel Fuhrmann.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:35:34 +02:00
Jakub Bereżański
327331e374 t0302: check helper can handle empty credentials
Make sure the helper does not crash when blank username and password is
provided. If the helper can save such credentials, it should be able to
read them back.

Signed-off-by: Jakub Bereżański <kuba@berezanscy.pl>
2017-07-26 00:35:33 +02:00
Johannes Schindelin
efec8bfc91 mingw: special-case GIT_REDIRECT_STDERR=2>&1
The "2>&1" notation in POSIX shells implies that stderr is redirected to
stdout. Let's special-case this value for the environment variable
GIT_REDIRECT_STDERR to allow writing to the same destination as stdout.

The functionality was suggested by Jeff Hostetler.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:35:32 +02:00
Johannes Schindelin
0e6b6babe9 mingw: add experimental feature to redirect standard handles
On Windows, file handles need to be marked inheritable when they need to
be used as standard input/output/error handles for a newly spawned
process. The problem with that, of course, is that the "inheritable" flag
is global and therefore can wreak havoc with highly multi-threaded
applications: other spawned processes will *also* inherit those file
handles, despite having *other* input/output/error handles, and never
close the former handles because they do not know about them.

Let's introduce a set of environment variables (GIT_REDIRECT_STDIN and
friends) that point to files, or even better, named pipes and that are
used by the spawned Git process. This helps work around above-mentioned
issue: those named pipes will be opened in a non-inheritable way upon
startup, and no handles are passed around.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2017-07-26 00:35:32 +02:00
Junio C Hamano
4f0b213699 Merge branch 'mt/p4-parse-G-output'
Use "p4 -G" to make "p4 changes" output more Python-friendly
to parse.

* mt/p4-parse-G-output:
  git-p4: filter for {'code':'info'} in p4CmdList
  git-p4: parse marshal output "p4 -G" in p4 changes
  git-p4: git-p4 tests with p4 triggers
2017-07-20 16:30:00 -07:00
Junio C Hamano
d5bfa469f4 Merge branch 'jk/test-copy-bytes-fix'
A test fix.

* jk/test-copy-bytes-fix:
  t: handle EOF in test_copy_bytes()
2017-07-20 16:29:59 -07:00
Junio C Hamano
099b74b4b2 Merge branch 'js/alias-case-sensitivity'
A recent update broke an alias that contained an uppercase letter.

* js/alias-case-sensitivity:
  alias: compare alias name *case-insensitively*
  t1300: demonstrate that CamelCased aliases regressed
2017-07-20 16:29:59 -07:00
Junio C Hamano
764046f6b0 Merge branch 'jk/gc-pre-detach-under-hook'
We run an early part of "git gc" that deals with refs before
daemonising (and not under lock) even when running a background
auto-gc, which caused multiple gc processes attempting to run the
early part at the same time.  This is now prevented by running the
early part also under the GC lock.

* jk/gc-pre-detach-under-hook:
  gc: run pre-detach operations under lock
2017-07-18 12:48:10 -07:00
Junio C Hamano
33400c0e96 Merge branch 'tb/push-to-cygwin-unc-path'
On Cygwin, similar to Windows, "git push //server/share/repository"
ought to mean a repository on a network share that can be accessed
locally, but this did not work correctly due to stripping the double
slashes at the beginning.

This may need to be heavily tested before it gets unleashed to the
wild, as the change is at a fairly low-level code and would affect
not just the code to decide if the push destination is local.  There
may be unexpected fallouts in the path normalization.

* tb/push-to-cygwin-unc-path:
  cygwin: allow pushing to UNC paths
2017-07-18 12:48:09 -07:00
Jeff King
f7f6dc340e t: handle EOF in test_copy_bytes()
The test_copy_bytes() function claims to read up to N bytes,
or until it gets EOF. But we never handle EOF in our loop,
and a short input will cause perl to go into an infinite
loop of read() getting zero bytes.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-17 14:55:43 -07:00
Johannes Schindelin
643df7e234 alias: compare alias name *case-insensitively*
It is totally legitimate to add CamelCased aliases, but due to the way
config keys are compared, the case does not matter.

Therefore, we must compare the alias name insensitively to the config
keys.

This fixes a regression introduced by a9bcf6586d (alias: use
the early config machinery to expand aliases, 2017-06-14).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-17 14:00:12 -07:00
Johannes Schindelin
084b044093 t1300: demonstrate that CamelCased aliases regressed
It is totally legitimate to add CamelCased aliases, but due to the way
config keys are compared, the case does not matter.

Except that now it does: the alias name is expected to be all
lower-case. This is a regression introduced by a9bcf6586d (alias: use
the early config machinery to expand aliases, 2017-06-14).

Noticed by Alejandro Pauly, diagnosed by Kevin Willford.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-17 14:00:04 -07:00
Junio C Hamano
757e9874be Merge branch 'jk/build-with-asan'
The build procedure has been improved to allow building and testing
Git with address sanitizer more easily.

* jk/build-with-asan:
  Makefile: disable unaligned loads with UBSan
  Makefile: turn off -fomit-frame-pointer with sanitizers
  Makefile: add helper for compiling with -fsanitize
  test-lib: turn on ASan abort_on_error by default
  test-lib: set ASAN_OPTIONS variable before we run git
2017-07-13 16:14:54 -07:00
Junio C Hamano
c9c63ee558 Merge branch 'sb/pull-rebase-submodule'
"git pull --rebase --recurse-submodules" learns to rebase the
branch in the submodules to an updated base.

* sb/pull-rebase-submodule:
  builtin/fetch cleanup: always set default value for submodule recursing
  pull: optionally rebase submodules (remote submodule changes only)
  builtin/fetch: parse recurse-submodules-default at default options parsing
  builtin/fetch: factor submodule recurse parsing out to submodule config
2017-07-13 16:14:54 -07:00
Junio C Hamano
91f6922544 Merge branch 'sb/hashmap-customize-comparison'
Update the hashmap API so that data to customize the behaviour of
the comparison function can be specified at the time a hashmap is
initialized.

* sb/hashmap-customize-comparison:
  hashmap: migrate documentation from Documentation/technical into header
  patch-ids.c: use hashmap correctly
  hashmap.h: compare function has access to a data field
2017-07-13 16:14:54 -07:00
Miguel Torroja
1997e91f4b git-p4: filter for {'code':'info'} in p4CmdList
The function p4CmdList accepts a new argument: skip_info. When set to
True it ignores any 'code':'info' entry (skip_info=False by default).

That allows us to fix some of the tests in t9831-git-p4-triggers.sh
known to be broken with verobse p4 triggers

Signed-off-by: Miguel Torroja <miguel.torroja@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-13 10:52:42 -07:00
Miguel Torroja
b596b3b920 git-p4: parse marshal output "p4 -G" in p4 changes
The option -G of p4 (python marshal output) gives more context about the
data being output. That's useful when using the command "change -o" as
we can distinguish between warning/error line and real change description.

This fixes the case where a p4 trigger for  "p4 change" is set and the command git-p4 submit is run.

Signed-off-by: Miguel Torroja <miguel.torroja@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-13 10:52:40 -07:00
Miguel Torroja
c625bf0ee8 git-p4: git-p4 tests with p4 triggers
Some p4 triggers in the server side generate some warnings when
executed. Unfortunately those messages are mixed with the output of
p4 commands. A few git-p4 commands don't expect extra messages or output
lines and may fail with verbose triggers.
New tests added are known to be broken.

Signed-off-by: Miguel Torroja <miguel.torroja@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-13 10:52:37 -07:00
Junio C Hamano
55bdfa022f Merge branch 'kn/ref-filter-branch-list' into maint
The rewrite of "git branch --list" using for-each-ref's internals
that happened in v2.13 regressed its handling of color.branch.local;
this has been fixed.

* kn/ref-filter-branch-list:
  ref-filter.c: drop return from void function
  branch: set remote color in ref-filter branch immediately
  branch: use BRANCH_COLOR_LOCAL in ref-filter format
  branch: only perform HEAD check for local branches
2017-07-12 15:23:09 -07:00
Junio C Hamano
9d21a968b2 Merge branch 'jk/reflog-walk-maint' into maint
After "git branch --move" of the currently checked out branch, the
code to walk the reflog of HEAD via "log -g" and friends
incorrectly stopped at the reflog entry that records the renaming
of the branch.

* jk/reflog-walk-maint:
  reflog-walk: include all fields when freeing complete_reflogs
  reflog-walk: don't free reflogs added to cache
  reflog-walk: duplicate strings in complete_reflogs list
  reflog-walk: skip over double-null oid due to HEAD rename
2017-07-12 15:20:36 -07:00
Junio C Hamano
768d0fe0da Merge branch 'kn/ref-filter-branch-list'
The rewrite of "git branch --list" using for-each-ref's internals
that happened in v2.13 regressed its handling of color.branch.local;
this has been fixed.

* kn/ref-filter-branch-list:
  ref-filter.c: drop return from void function
  branch: set remote color in ref-filter branch immediately
  branch: use BRANCH_COLOR_LOCAL in ref-filter format
  branch: only perform HEAD check for local branches
2017-07-12 15:18:23 -07:00
Jeff King
c45af94dbc gc: run pre-detach operations under lock
We normally try to avoid having two auto-gc operations run
at the same time, because it wastes resources. This was done
long ago in 64a99eb47 (gc: reject if another gc is running,
unless --force is given, 2013-08-08).

When we do a detached auto-gc, we run the ref-related
commands _before_ detaching, to avoid confusing lock
contention. This was done by 62aad1849 (gc --auto: do not
lock refs in the background, 2014-05-25).

These two features do not interact well. The pre-detach
operations are run before we check the gc.pid lock, meaning
that on a busy repository we may run many of them
concurrently. Ideally we'd take the lock before spawning any
operations, and hold it for the duration of the program.

This is tricky, though, with the way the pid-file interacts
with the daemonize() process.  Other processes will check
that the pid recorded in the pid-file still exists. But
detaching causes us to fork and continue running under a
new pid. So if we take the lock before detaching, the
pid-file will have a bogus pid in it. We'd have to go back
and update it with the new pid after detaching. We'd also
have to play some tricks with the tempfile subsystem to
tweak the "owner" field, so that the parent process does not
clean it up on exit, but the child process does.

Instead, we can do something a bit simpler: take the lock
only for the duration of the pre-detach work, then detach,
then take it again for the post-detach work. Technically,
this means that the post-detach lock could lose to another
process doing pre-detach work. But in the long run this
works out.

That second process would then follow-up by doing
post-detach work. Unless it was in turn blocked by a third
process doing pre-detach work, and so on. This could in
theory go on indefinitely, as the pre-detach work does not
repack, and so need_to_gc() will continue to trigger.  But
in each round we are racing between the pre- and post-detach
locks. Eventually, one of the post-detach locks will win the
race and complete the full gc. So in the worst case, we may
racily repeat the pre-detach work, but we would never do so
simultaneously (it would happen via a sequence of serialized
race-wins).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-12 09:41:04 -07:00
Junio C Hamano
8e7b78a692 Merge branch 'js/fsck-name-object' into maint
Test fix.

* js/fsck-name-object:
  t1450: use egrep for regexp "alternation"
2017-07-10 13:59:08 -07:00
Junio C Hamano
5a24b4e14a Merge branch 'js/t5534-rev-parse-gives-multi-line-output-fix' into maint
A few tests that tried to verify the contents of push certificates
did not use 'git rev-parse' to formulate the line to look for in
the certificate correctly.

* js/t5534-rev-parse-gives-multi-line-output-fix:
  t5534: fix misleading grep invocation
2017-07-10 13:59:07 -07:00