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It allows for more consistent patches that way.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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We want to make them relative to the top-level directory.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Windows fixes.
* js/mingw-fixes:
mingw: support Windows Server 2016 again
mingw_rename: support ReFS on Windows 2022
mingw: drop Windows 7-specific work-around
mingw_open_existing: handle directories better
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The config API had a set of convenience wrapper functions that
implicitly use the_repository instance; they have been removed and
inlined at the calling sites.
* ps/config-wo-the-repository: (21 commits)
config: fix sign comparison warnings
config: move Git config parsing into "environment.c"
config: remove unused `the_repository` wrappers
config: drop `git_config_set_multivar()` wrapper
config: drop `git_config_get_multivar_gently()` wrapper
config: drop `git_config_set_multivar_in_file_gently()` wrapper
config: drop `git_config_set_in_file_gently()` wrapper
config: drop `git_config_set()` wrapper
config: drop `git_config_set_gently()` wrapper
config: drop `git_config_set_in_file()` wrapper
config: drop `git_config_get_bool()` wrapper
config: drop `git_config_get_ulong()` wrapper
config: drop `git_config_get_int()` wrapper
config: drop `git_config_get_string()` wrapper
config: drop `git_config_get_string()` wrapper
config: drop `git_config_get_string_multi()` wrapper
config: drop `git_config_get_value()` wrapper
config: drop `git_config_get_value()` wrapper
config: drop `git_config_get()` wrapper
config: drop `git_config_clear()` wrapper
...
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It was reported to the Git for Windows project that a simple `git init`
fails on Windows Server 2016:
D:\Dev\test> git init
error: could not write config file D:/Dev/test/.git/config: Function not implemented
fatal: could not set 'core.repositoryformatversion' to '0'
According to https://endoflife.date/windows-server, Windows Server 2016
is officially supported for another one-and-a-half years as of time of
writing, so this is not good.
The culprit is the `mingw_rename()` changes that try to use POSIX
semantics when available, but fail to fall back properly on Windows
Server 2016.
This fixes https://github.com/git-for-windows/git/issues/5695.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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ReFS is an alternative filesystem to NTFS. On Windows 2022, it seems not
to support the rename operation using POSIX semantics that Git uses on
Windows as of 391bceae4350 (compat/mingw: support POSIX semantics for
atomic renames, 2024-10-27).
However, Windows 2022 reports `ERROR_NOT_SUPPORTED` in this instance.
This is in contrast to `ERROR_INVALID_PARAMETER` (as previous Windows
versions would report that do not support POSIX semantics in renames at
all).
Let's handle both errors the same: by falling back to the best-effort
option, namely to rename without POSIX semantics.
This fixes https://github.com/git-for-windows/git/issues/5427
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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In ac33519ddfa8 (mingw: restrict file handle inheritance only on Windows
7 and later, 2019-11-22), I introduced code to safe-guard the
defense-in-depth handling that restricts handles' inheritance so that it
would work with Windows 7, too.
Let's revert this patch: Git for Windows dropped supporting Windows 7 (and
Windows 8) directly after Git for Windows v2.46.2. For full details, see
https://gitforwindows.org/requirements#windows-version.
Actually, on second thought: revert only the part that makes this handle
inheritance restriction logic optional and that suggests to open a bug
report if it fails, but keep the fall-back to try again without said
logic: There have been a few false positives over the past few years
(where the warning was triggered e.g. because Defender was still
accessing a file that Git wanted to overwrite), and the fall-back logic
seems to have helped occasionally in such situations.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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CreateFileW() requires FILE_FLAG_BACKUP_SEMANTICS to create a directory
handle [1] and errors out with ERROR_ACCESS_DENIED without this flag.
Fall back to accessing Directory handles this way.
[1] https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew#directories
This fixes https://github.com/git-for-windows/git/issues/5068
Signed-off-by: Matthias Aßhauer <mha1993@live.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Clean-up compat/bswap.h mess.
* ss/compat-bswap-revamp:
bswap.h: provide a built-in based version of bswap32/64 if possible
bswap.h: remove optimized x86 version of bswap32/64
bswap.h: always overwrite ntohl/ ntohll macros
bswap.h: define GIT_LITTLE_ENDIAN on msvc as little endian
bswap.h: add support for __BYTE_ORDER__
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In 036876a1067 (config: hide functions using `the_repository` by
default, 2024-08-13) we have moved around a bunch of functions in the
config subsystem that depend on `the_repository`. Those function have
been converted into mere wrappers around their equivalent function that
takes in a repository as parameter, and the intent was that we'll
eventually remove those wrappers to make the dependency on the global
repository variable explicit at the callsite.
Follow through with that intent and remove `git_config_set()`. All
callsites are adjusted so that they use `repo_config_set(the_repository,
...)` instead. While some callsites might already have a repository
available, this mechanical conversion is the exact same as the current
situation and thus cannot cause any regression. Those sites should
eventually be cleaned up in a later patch series.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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In 036876a1067 (config: hide functions using `the_repository` by
default, 2024-08-13) we have moved around a bunch of functions in the
config subsystem that depend on `the_repository`. Those function have
been converted into mere wrappers around their equivalent function that
takes in a repository as parameter, and the intent was that we'll
eventually remove those wrappers to make the dependency on the global
repository variable explicit at the callsite.
Follow through with that intent and remove `git_config_get_bool()`. All
callsites are adjusted so that they use
`repo_config_get_bool(the_repository, ...)` instead. While some
callsites might already have a repository available, this mechanical
conversion is the exact same as the current situation and thus cannot
cause any regression. Those sites should eventually be cleaned up in a
later patch series.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The compiler is in general able to recognize the endian shift and
replace it with an optimized opcode if possible. On certain
architectures such as RiscV or MIPS the situation can get complicated.
They don't provide an optimized opcode and masking the "higher" bits may
required loading a constant which needs shifting. This causes the
compiler to emit a lot of instructions for the operation.
The provided builtin directive on these architecture calls a function
which does the operation instead of emitting the code for operation.
Bring back the change from commit 6547d1c9 (bswap.h: add support for
built-in bswap functions, 2025-04-23). The bswap32/64 macro can now be
defined unconditionally so it won't regress on big endian architectures.
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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On x86 the bswap32/64 macro is implemented based on the x86 opcode which
performs the required shifting in just one opcode.
The other CPUs fallback to the generic shifting as implemented by
default_swab32() and default_bswap64() if needed.
I've been looking at how good a compiler is at recognizing the default
shift and emitting an optimized operation:
- x86, arm64 msvc v19.20
default_swab32() optimized
default_bswap64() shifts
_byteswap_uint64() optimized
- x86, arm64 msvc v19.37
default_swab32() optimized
default_bswap64() optimized
_byteswap_uint64() optimized
- arm64, gcc-4.9.4: optimized
- x86-64, gcc-4.4.7: shifts
- x86-64, gcc-4.5.3: optimized
- x86-64, clang-3.0: optimized
Given that gcc-4.5 and clang-3.0 are fairly old, any recent compiler
should recognize the shift.
Remove the optimized x86 version and rely on the compiler.
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The ntohl and htonl macros are redefined because the provided macros were
not always optimal. Sometimes it was a function call, sometimes it was a
macro which did the shifting. Using the 'bswap' opcode on x86 provides
probably better performance than performing the shifting.
These macros are only overwritten on x86 if the "optimized" version is
available.
The ntohll and htonll macros are not available on every platform (at
least glibc does not provide them) which means they need to be defined
once the endianness of the system is determined.
In order to get a more symmetrical setup, redfine the macros once the
endianness of the system has been determined.
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The Microsoft Visual C++ (MSVC) compiler (as of Visual Studio 2022
version 17.13.6) does not define __BYTE_ORDER__ and its C-library does
not define __BYTE_ORDER. The compiler is supported only on arm64 and x86
which are all little endian.
Define GIT_BYTE_ORDER on msvc as little endian to avoid further checks.
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The __BYTE_ORDER__ define is provided by gcc (since ~v4.6), clang
(since ~v3.2) and icc (since ~16.0.3).
The __BYTE_ORDER and BYTE_ORDER macros are libc specific and are not
available on all supported platforms such as mingw.
Add support for the __BYTE_ORDER__ macro as a fallback.
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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A future change will start using sigaction to setup a SIGCHLD signal
handler.
The current code uses signal(), which returns SIG_ERR (but doesn't
seem to set errno) so instruct sigaction() to do the same.
A new SA flag will be needed, so copy the one from Cygwin; note that
the sigaction() implementation that is provided won't use it, so
its value is otherwise irrelevant.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Revert a botched bswap.h change that broke ntohll() functions on
big-endian systems with __builtin_bswap32/64().
* ss/revert-builtin-bswap-stuff:
Revert "bswap.h: add support for built-in bswap functions"
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* ss/revert-builtin-bswap-stuff:
Revert "bswap.h: add support for built-in bswap functions"
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Since 6547d1c9 (bswap.h: add support for built-in bswap
functions, 2025-04-23) tweaked the way the bswap32/64 macros are
defined, on platforms with __builtin_bswap32/64 supported, the
bswap32/64 macros are defined even on big endian platforms.
However the rest of this file assumes that bswap32/64() are defined
ONLY on little endian machines and uses that assumption to redefine
ntohl/ntohll macros. The said commit broke t4014-format-patch.sh test,
among many others on s390x.
Revert the commit.
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Handle OpenBSD and NetBSD as FreeBSD / DragonFly are. OpenBSD would
need _XOPEN_SOURCE to be set to 700. Its simpler to just not set
_XOPEN_SOURCE.
CC strbuf.o
strbuf.c:645:6: warning: call to undeclared function 'getdelim'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
r = getdelim(&sb->buf, &sb->alloc, term, fp);
^
1 warning generated.
Signed-off-by: Brad Smith <brad@comstyle.com>
Reviewed-by: Collin Funk <collin.funk1@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Update to arm64 Windows port.
* js/windows-arm64:
max_tree_depth: lower it for clangarm64 on Windows
mingw(arm64): do move the `/etc/git*` location
msvc: do handle builds on Windows/ARM64
mingw: do not use nedmalloc on Windows/ARM64
config.mak.uname: add support for clangarm64
bswap.h: add support for built-in bswap functions
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Overhaul of the reftable API.
* ps/reftable-api-revamp:
reftable/table: move printing logic into test helper
reftable/constants: make block types part of the public interface
reftable/table: introduce iterator for table blocks
reftable/table: add `reftable_table` to the public interface
reftable/block: expose a generic iterator over reftable records
reftable/block: make block iterators reseekable
reftable/block: store block pointer in the block iterator
reftable/block: create public interface for reading blocks
git-zlib: use `struct z_stream_s` instead of typedef
reftable/block: rename `block_reader` to `reftable_block`
reftable/block: rename `block` to `block_data`
reftable/table: move reading block into block reader
reftable/block: simplify how we track restart points
reftable/blocksource: consolidate code into a single file
reftable/reader: rename data structure to "table"
reftable: fix formatting of the license header
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Code clean-up.
* ps/object-file-cleanup:
object-store: merge "object-store-ll.h" and "object-store.h"
object-store: remove global array of cached objects
object: split out functions relating to object store subsystem
object-file: drop `index_blob_stream()`
object-file: split up concerns of `HASH_*` flags
object-file: split out functions relating to object store subsystem
object-file: move `xmmap()` into "wrapper.c"
object-file: move `git_open_cloexec()` to "compat/open.c"
object-file: move `safe_create_leading_directories()` into "path.c"
object-file: move `mkdir_in_gitdir()` into "path.c"
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Newer compiler versions, like GCC 10 and Clang 12, have built-in
functions for bswap32 and bswap64. This comes in handy, for example,
when targeting CLANGARM64 on Windows, which would not be supported
without this logic.
Signed-off-by: Dennis Ameling <dennis@dennisameling.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Code clean-up.
* js/comma-semicolon-confusion:
detect-compiler: detect clang even if it found CUDA
clang: warn when the comma operator is used
compat/regex: explicitly mark intentional use of the comma operator
wildmatch: avoid using of the comma operator
diff-delta: avoid using the comma operator
xdiff: avoid using the comma operator unnecessarily
clar: avoid using the comma operator unnecessarily
kwset: avoid using the comma operator unnecessarily
rebase: avoid using the comma operator unnecessarily
remote-curl: avoid using the comma operator unnecessarily
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Fix lockfile contention in reftable code on Windows.
* ps/mingw-creat-excl-fix:
compat/mingw: fix EACCESS when opening files with `O_CREAT | O_EXCL`
meson: fix compat sources when compiling with MSVC
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Portability fix.
* ps/reftable-windows-unlink-fix:
reftable: ignore file-in-use errors when unlink(3p) fails on Windows
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The `git_open_cloexec()` wrapper function provides the ability to open a
file with `O_CLOEXEC` in a platform-agnostic way. This function is
provided by "object-file.c" even though it is not specific to the object
subsystem at all.
Move the file into "compat/open.c". This file already exists before this
commit, but has only been compiled conditionally depending on whether or
not open(3p) may return EINTR. With this change we now unconditionally
compile the object, but wrap `git_open_with_retry()` in an ifdef.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Make the code in reftable library less reliant on the service
routines it used to borrow from Git proper, to make it easier to
use by external users of the library.
* ps/reftable-sans-compat-util:
Makefile: skip reftable library for Coccinelle
reftable: decouple from Git codebase by pulling in "compat/posix.h"
git-compat-util.h: split out POSIX-emulating bits
compat/mingw: split out POSIX-related bits
reftable/basics: introduce `REFTABLE_UNUSED` annotation
reftable/basics: stop using `SWAP()` macro
reftable/stack: stop using `sleep_millisec()`
reftable/system: introduce `reftable_rand()`
reftable/reader: stop using `ARRAY_SIZE()` macro
reftable/basics: provide wrappers for big endian conversion
reftable/basics: stop using `st_mult()` in array allocators
reftable: stop using `BUG()` in trivial cases
reftable/record: don't `BUG()` in `reftable_record_cmp()`
reftable/record: stop using `BUG()` in `reftable_record_init()`
reftable/record: stop using `COPY_ARRAY()`
reftable/blocksource: stop using `xmmap()`
reftable/stack: stop using `write_in_full()`
reftable/stack: stop using `read_in_full()`
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Throughout the Git codebase we're using the typedeffed version of
`z_stream`, which maps to `struct z_stream_s`. By using a typedef
instead of the struct it becomes somewhat harder to predeclare the
symbol so that headers depending on the struct can do so without having
to pull in "zlib-compat.h".
We don't yet have users that would really care about this: the only
users that declare `z_stream` as a pointer are in "reftable/block.h",
which is a header that is internal to the reftable library. But in the
next step we're going to expose the `struct reftable_block` publicly,
and that struct does contain a pointer to `z_stream`. And as the public
header shouldn't depend on "reftable/system.h", which is an internal
implementation detail, we won't have the typedef for `z_stream` readily
available.
Prepare for this change by using `struct z_stream_s` throughout our code
base. In case zlib-ng is used we use a define to map from `z_stream_s`
to `zng_stream_s`.
Drop the pre-declaration of `struct z_stream` while at it. This struct
does not exist in the first place, and the declaration wasn't needed
because "reftable/block.h" already includes "reftable/basics.h" which
transitively includes "reftable/system.h" and thus "git-zlib.h".
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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* ps/reftable-sans-compat-util:
Makefile: skip reftable library for Coccinelle
reftable: decouple from Git codebase by pulling in "compat/posix.h"
git-compat-util.h: split out POSIX-emulating bits
compat/mingw: split out POSIX-related bits
reftable/basics: introduce `REFTABLE_UNUSED` annotation
reftable/basics: stop using `SWAP()` macro
reftable/stack: stop using `sleep_millisec()`
reftable/system: introduce `reftable_rand()`
reftable/reader: stop using `ARRAY_SIZE()` macro
reftable/basics: provide wrappers for big endian conversion
reftable/basics: stop using `st_mult()` in array allocators
reftable: stop using `BUG()` in trivial cases
reftable/record: don't `BUG()` in `reftable_record_cmp()`
reftable/record: stop using `BUG()` in `reftable_record_init()`
reftable/record: stop using `COPY_ARRAY()`
reftable/blocksource: stop using `xmmap()`
reftable/stack: stop using `write_in_full()`
reftable/stack: stop using `read_in_full()`
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The comma operator is a somewhat obscure C feature that is often used by
mistake and can even cause unintentional code flow. That is why the
`-Wcomma` option of clang was introduced: To identify unintentional uses
of the comma operator.
In the `compat/regex/` code, the comma operator is used twice, once to
avoid surrounding two conditional statements with curly brackets, the
other one to increment two counters simultaneously in a `do ... while`
condition.
The first one is replaced with a proper conditional block, surrounded by
curly brackets.
The second one would be harder to replace because the loop contains two
`continue`s. Therefore, the second one is marked as intentional by
casting the value-to-discard to `void`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Acked-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The check for dubious ownership has one particular quirk on Windows: if
running as an administrator, files owned by the Administrators _group_
are considered owned by the user.
The rationale for that is: When running in elevated mode, Git creates
files that aren't owned by the individual user but by the Administrators
group.
There is yet another quirk, though: The check I introduced to determine
whether the current user is an administrator uses the
`CheckTokenMembership()` function with the current process token. And
that check only succeeds when running in elevated mode!
Let's be a bit more lenient here and look harder whether the current
user is an administrator. We do this by looking for a so-called "linked
token". That token exists when administrators run in non-elevated mode,
and can be used to create a new process in elevated mode. And feeding
_that_ token to the `CheckTokenMembership()` function succeeds!
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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In our CI systems we can observe that t0610 fails rather frequently.
This testcase races a bunch of git-update-ref(1) processes with one
another which are all trying to update a unique reference, where we
expect that all processes succeed and end up updating the reftable
stack. The error message in this case looks like the following:
fatal: update_ref failed for ref 'refs/heads/branch-88': reftable: transaction prepare: I/O error
Instrumenting the code with a couple of calls to `BUG()` in relevant
sites where we return `REFTABLE_IO_ERROR` quickly leads one to discover
that this error is caused when calling `flock_acquire()`, which is a
thin wrapper around our lockfile API. Curiously, the error code we get
in such cases is `EACCESS`, indicating that we are not allowed to access
the file.
The root cause of this is an oddity of `CreateFileW()`, which is what
`_wopen()` uses internally. Quoting its documentation [1]:
If you call CreateFile on a file that is pending deletion as a
result of a previous call to DeleteFile, the function fails. The
operating system delays file deletion until all handles to the file
are closed. GetLastError returns ERROR_ACCESS_DENIED.
This behaviour is triggered quite often in the above testcase because
all the processes race with one another trying to acquire the lock for
the "tables.list" file. This is due to how locking works in the reftable
library when compacting a stack:
1. Lock the "tables.list" file and reads its contents.
2. Decide which tables to compact.
3. Lock each of the individual tables that we are about to compact.
4. Unlock the "tables.list" file.
5. Compact the individual tables into one large table.
6. Re-lock the "tables.list" file.
7. Write the new list of tables into it.
8. Commit the "tables.list" file.
The important step is (4): we don't commit the file directly by renaming
it into place, but instead we delete the lockfile so that concurrent
processes can continue to append to the reftable stack while we compact
the tables. And because we use `DeleteFileW()` to do so, we may now race
with another process that wants to acquire that lockfile. So if we are
unlucky, we would now see `ERROR_ACCESS_DENIED` instead of the expected
`ERROR_FILE_EXISTS`, which the lockfile subsystem isn't prepared to
handle and thus it will bail out without retrying to acquire the lock.
In theory, the issue is not limited to the reftable library and can be
triggered by every other user of the lockfile subsystem, as well. My gut
feeling tells me it's rather unlikely to surface elsewhere though.
Fix the issue by translating the error to `EEXIST`. This makes the
lockfile subsystem handle the error correctly: in case a timeout is set
it will now retry acquiring the lockfile until the timeout has expired.
With this, t0610 is now always passing on my machine whereas it was
previously failing in around 20-30% of all test runs.
[1]: https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The path.[ch] API takes an explicit repository parameter passed
throughout the callchain, instead of relying on the_repository
singleton instance.
* ps/path-sans-the-repository:
path: adjust last remaining users of `the_repository`
environment: move access to "core.sharedRepository" into repo settings
environment: move access to "core.hooksPath" into repo settings
repo-settings: introduce function to clear struct
path: drop `git_path()` in favor of `repo_git_path()`
rerere: let `rerere_path()` write paths into a caller-provided buffer
path: drop `git_common_path()` in favor of `repo_common_path()`
worktree: return allocated string from `get_worktree_git_dir()`
path: drop `git_path_buf()` in favor of `repo_git_path_replace()`
path: drop `git_pathdup()` in favor of `repo_git_path()`
path: drop unused `strbuf_git_path()` function
path: refactor `repo_submodule_path()` family of functions
submodule: refactor `submodule_to_gitdir()` to accept a repo
path: refactor `repo_worktree_path()` family of functions
path: refactor `repo_git_path()` family of functions
path: refactor `repo_common_path()` family of functions
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Since 183ea3ea (Merge branch 'ps/mingw-rename', 2024-11-13),
a new technique is used on Windows to rename files, where supported.
The first step of this technique is to open the file with
`CreateFileW`. At that time, `FILE_ATTRIBUTE_NORMAL` was passed as
the value of the `dwFlagsAndAttributes` argument. In b30404df [2], this
was improved by passing `FILE_FLAG_BACKUP_SEMANTICS`, to support
directories as well as regular files.
However, neither value of `dwFlagsAndAttributes` is sufficient to open
a symbolic link with the correct semantics to rename it. Symlinks on
Windows are reparse points. Attempting to open a reparse point with
`CreateFileW` dereferences the reparse point and opens the target
instead, unless `FILE_FLAG_OPEN_REPARSE_POINT` is included in
`dwFlagsAndAttributes`. This is documented for that flag and in the
"Symbolic Link Behavior" section of the `CreateFileW` docs [3].
This produces a regression where attempting to rename a symlink on
Windows renames its target to the intended new name and location of the
symlink. For example, if `symlink` points to `file`, then running
git mv symlink symlink-renamed
leaves `symlink` in place and unchanged, but renames `file` to
`symlink-renamed` [4].
This regression is detectable by existing tests in `t7001-mv.sh`, but
the tests must be run by a Windows user with the ability to create
symlinks, and the `ln -s` command used to create the initial symlink
must also be able to create a real symlink (such as by setting the
`MSYS` environment variable to `winsymlinks:nativestrict`). Then
these two tests fail if the regression is present, and pass otherwise:
38 - git mv should overwrite file with a symlink
39 - check moved symlink
Let's fix this, so that renaming a symlink again renames the symlink
itself and leaves the target unchanged, by passing
FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT
as the `dwFlagsAndAttributes` argument. This is sufficient (and safe)
because including `FILE_FLAG_OPEN_REPARSE_POINT` causes no harm even
when used to open a file or directory that is not a reparse point. In
that case, as noted in [3], this flag is simply ignored.
[1]: https://github.com/git-for-windows/git/commit/183ea3eabf81822506d2cd3aa1dc0727099ebccd
[2]: https://github.com/git-for-windows/git/commit/b30404dfc04a4b087b630aea4ab88a51cd3a7459
[3]: https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew
[4]: https://github.com/git-for-windows/git/issues/5436
Signed-off-by: Eliah Kagan <eliah.kagan@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Unlinking a file may fail on Windows systems when the file is still held
open by another process. This is incompatible with POSIX semantics and
by extension with Git's assumed semantics when unlinking files, which
is that files can be unlinked regardless of whether they are still open
or not. To counteract this incompatibility, we have some custom error
handling in the `mingw_unlink()` wrapper that first retries the deletion
with some delay, and then asks the user whether we should continue to
retry.
While this logic might be sensible in many callsites throughout Git, it
is less when used in the reftable library. We only use unlink(3) there
to delete tables which aren't referenced anymore, and the code is very
aware of the limitations on Windows. As such, all calls to unlink(3p)
don't perform any error checking at all and are fine with the call
failing.
Instead, the library provides the `reftable_stack_clean()` function,
which Git knows to execute in git-pack-refs(1) after compacting a stack.
The effect of this function is that all stale tables will eventually get
deleted once they aren't kept open anymore.
So while we're fine with unlink(3p) failing, the Windows-emulation of
that function will still perform several sleeps and ultimately end up
asking the user:
$ git pack-refs
Unlink of file 'C:/temp/jgittest/jgit/.git/reftable/0x000000000002-0x000000000004-50486d0e.ref' failed. Should I try again? (y/n) n
Unlink of file 'C:/temp/jgittest/jgit/.git/reftable/0x000000000002-0x000000000004-50486d0e.ref' failed. Should I try again? (y/n) n
Unlink of file 'C:/temp/jgittest/jgit/.git/reftable/0x000000000002-0x000000000004-50486d0e.ref' failed. Should I try again? (y/n) n
It even asks multiple times, which is doubly annoying and puzzling to
the user:
1. It asks when trying to delete the old file after having written the
compacted stack.
2. It asks when reloading the stack, where it will try to unlink
now-unreferenced tables.
3. It asks when calling `reftable_stack_clean()`, where it will try to
unlink now-stale tables.
Fix the issue by making it possible to disable this behaviour with a
preprocessor define. As "git-compat-util.h" is only included from
"system.h", and given that "system.h" is only ever included by headers
and code that are internal to the reftable library, we can set that
macro in this header without impacting anything else but the reftable
library.
Reported-by: Christian Reich <Zottelbart@t-online.de>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The "git-compat-util.h" header is a treasure trove of various bits and
pieces used throughout the project. It basically mixes two different
things into one:
- Providing a POSIX-like interface even on platforms that aren't
POSIX-compliant.
- Providing low-level functionality that is specific to Git.
This intermixing is a bit of a problem for the reftable library as we
don't want to recreate the POSIX-like interface there. But neither do we
want to pull in the Git-specific functionality, as it is otherwise quite
easy to start depending on the Git codebase again.
Split out a new header "compat/posix.h" that only contains the bits and
pieces relevant for the emulation of POSIX, which we will start using in
the next commit.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Split out POSIX-related bits from "compat/mingw.h" and "compat/msvc.h".
This is in preparation for splitting up "git-compat-utils.h" into a
header that provides POSIX-compatibility and a header that provides
common wrappers used by the Git project.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Remove `git_path_buf()` in favor of `repo_git_path_replace()`. The
latter does essentially the same, with the only exception that it does
not rely on `the_repository` but takes the repo as separate parameter.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The code paths to interact with zlib has been cleaned up in
preparation for building with zlib-ng.
* ps/zlib-ng:
ci: make "linux-musl" job use zlib-ng
ci: switch linux-musl to use Meson
compat/zlib: allow use of zlib-ng as backend
git-zlib: cast away potential constness of `next_in` pointer
compat/zlib: provide stubs for `deflateSetHeader()`
compat/zlib: provide `deflateBound()` shim centrally
git-compat-util: move include of "compat/zlib.h" into "git-zlib.h"
compat: introduce new "zlib.h" header
git-compat-util: drop `z_const` define
compat: drop `uncompress2()` compatibility shim
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The zlib-ng library is a hard fork of the old and venerable zlib
library. It describes itself as zlib replacement with optimizations for
"next generation" systems. As such, it contains several implementations
of central algorithms using for example SSE2, AVX2 and other vectorized
CPU intrinsics that supposedly speed up in- and deflating data.
And indeed, compiling Git against zlib-ng leads to a significant speedup
when reading objects. The following benchmark uses git-cat-file(1) with
`--batch --batch-all-objects` in the Git repository:
Benchmark 1: zlib
Time (mean ± σ): 52.085 s ± 0.141 s [User: 51.500 s, System: 0.456 s]
Range (min … max): 52.004 s … 52.335 s 5 runs
Benchmark 2: zlib-ng
Time (mean ± σ): 40.324 s ± 0.134 s [User: 39.731 s, System: 0.490 s]
Range (min … max): 40.135 s … 40.484 s 5 runs
Summary
zlib-ng ran
1.29 ± 0.01 times faster than zlib
So we're looking at a ~25% speedup compared to zlib. This is of course
an extreme example, as it makes us read through all objects in the
repository. But regardless, it should be possible to see some sort of
speedup in most commands that end up accessing the object database.
The zlib-ng library provides a compatibility layer that makes it a
proper drop-in replacement for zlib: nothing needs to change in the
build system to support it. Unfortunately though, this mode isn't easy
to use on most systems because distributions do not allow you to install
zlib-ng in that way, as that would mean that the zlib library would be
globally replaced. Instead, many distributions provide a package that
installs zlib-ng without the compatibility layer. This version does
provide effectively the same APIs like zlib does, but all of the symbols
are prefixed with `zng_` to avoid symbol collisions.
Implement a new build option that allows us to link against zlib-ng
directly. If set, we redefine zlib symbols so that we use the `zng_`
prefixed versions thereof provided by that library. Like this, it
becomes possible to install both zlib and zlib-ng (without the compat
layer) and then pick whichever library one wants to link against for
Git.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The function `deflateSetHeader()` has been introduced with zlib v1.2.2.1,
so we don't use it when linking against an older version of it. Refactor
the code to instead provide a central stub via "compat/zlib.h" so that
we can adapt it based on whether or not we use zlib-ng in a subsequent
commit.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The `deflateBound()` function has only been introduced with zlib 1.2.0.
When linking against a zlib version older than that we thus provide our
own compatibility shim. Move this shim into "compat/zlib.h" so that we
can adapt it based on whether or not we use zlib-ng in a subsequent
commit.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Introduce a new "compat/zlib-compat.h" header that we include instead of
including <zlib.h> directly. This will allow us to wire up zlib-ng as an
alternative backend for zlib compression in a subsequent commit.
Note that we cannot just call the file "compat/zlib.h", as that may
otherwise cause us to include that file instead of <zlib.h>.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Our compat library has an implementation of zlib's `uncompress2()`
function that gets used when linking against an old version of zlib
that doesn't yet have it. The last user of `uncompress2()` got removed
in 15a60b747e (reftable/block: open-code call to `uncompress2()`,
2024-04-08), so the compatibility code is not required anymore. Drop it.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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It was possible for "git unpack-objects" and "git index-pack" to
make an unaligned access, which has been corrected.
* jk/pack-header-parse-alignment-fix:
index-pack, unpack-objects: use skip_prefix to avoid magic number
index-pack, unpack-objects: use get_be32() for reading pack header
parse_pack_header_option(): avoid unaligned memory writes
packfile: factor out --pack_header argument parsing
bswap.h: squelch potential sparse -Wcast-truncate warnings
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In put_be32(), we right-shift a uint32_t value various amounts and then
assign the low 8-bits to individual "unsigned char" bytes, throwing away
the high bits. For shifts smaller than 24 bits, those thrown away bits
will be arbitrary bits from the original uint32_t.
This works exactly as we want, but if you feed a constant, then sparse
complains. For example if we write this (which we plan to do in a future
patch):
put_be32(hdr, PACK_SIGNATURE);
then "make sparse" produces:
compat/bswap.h:175:22: error: cast truncates bits from constant value (5041 becomes 41)
compat/bswap.h:176:22: error: cast truncates bits from constant value (504143 becomes 43)
compat/bswap.h:177:22: error: cast truncates bits from constant value (5041434b becomes 4b)
And the same issue exists in the other put_be*() functions, when used
with a constant.
We can silence this warning by explicitly masking off the truncated
bits. The compiler is smart enough to know the result is the same, and
the asm generated by gcc (with both -O0 and -O2) is identical.
Curiously this line already exists:
put_be32(&hdr_version, INDEX_EXTENSION_VERSION2);
in the fsmonitor.c file, but it does not get flagged because the CPP
macro expands to a small integer (2).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Update the way rename() emulation on Windows handle directories to
correct an earlier attempt to do the same.
* js/mingw-rename-fix:
mingw_rename: do support directory renames
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