Commit Graph

111494 Commits

Author SHA1 Message Date
Jeff Hostetler
9652a232ef dir.c: make add_excludes aware of fscache during status
Teach read_directory_recursive() and add_excludes() to
be aware of optional fscache and avoid trying to open()
and fstat() non-existant ".gitignore" files in every
directory in the worktree.

The current code in add_excludes() calls open() and then
fstat() for a ".gitignore" file in each directory present
in the worktree.  Change that when fscache is enabled to
call lstat() first and if present, call open().

This seems backwards because both lstat needs to do more
work than fstat.  But when fscache is enabled, fscache will
already know if the .gitignore file exists and can completely
avoid the IO calls.  This works because of the lstat diversion
to mingw_lstat when fscache is enabled.

This reduced status times on a 350K file enlistment of the
Windows repo on a NVMe SSD by 0.25 seconds.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
2020-07-17 16:40:23 -04:00
Jeff Hostetler
d14c619882 add: use preload-index and fscache for performance
Teach "add" to use preload-index and fscache features
to improve performance on very large repositories.

During an "add", a call is made to run_diff_files()
which calls check_remove() for each index-entry.  This
calls lstat().  On Windows, the fscache code intercepts
the lstat() calls and builds a private cache using the
FindFirst/FindNext routines, which are much faster.

Somewhat independent of this, is the preload-index code
which distributes some of the start-up costs across
multiple threads.

We need to keep the call to read_cache() before parsing the
pathspecs (and hence cannot use the pathspecs to limit any preload)
because parse_pathspec() is using the index to determine whether a
pathspec is, in fact, in a submodule. If we would not read the index
first, parse_pathspec() would not error out on a path that is inside
a submodule, and t7400-submodule-basic.sh would fail with

	not ok 47 - do not add files from a submodule

We still want the nice preload performance boost, though, so we simply
call read_cache_preload(&pathspecs) after parsing the pathspecs.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:40:22 -04:00
Johannes Schindelin
49c3ea9089 fscache: add a test for the dir-not-found optimization
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:40:22 -04:00
Jeff Hostetler
59eaa92030 fscache: remember not-found directories
Teach FSCACHE to remember "not found" directories.

This is a performance optimization.

FSCACHE is a performance optimization available for Windows.  It
intercepts Posix-style lstat() calls into an in-memory directory
using FindFirst/FindNext.  It improves performance on Windows by
catching the first lstat() call in a directory, using FindFirst/
FindNext to read the list of files (and attribute data) for the
entire directory into the cache, and short-cut subsequent lstat()
calls in the same directory.  This gives a major performance
boost on Windows.

However, it does not remember "not found" directories.  When STATUS
runs and there are missing directories, the lstat() interception
fails to find the parent directory and simply return ENOENT for the
file -- it does not remember that the FindFirst on the directory
failed. Thus subsequent lstat() calls in the same directory, each
re-attempt the FindFirst.  This completely defeats any performance
gains.

This can be seen by doing a sparse-checkout on a large repo and
then doing a read-tree to reset the skip-worktree bits and then
running status.

This change reduced status times for my very large repo by 60%.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:40:22 -04:00
Jeff Hostetler
f2f92dd184 fscache: add key for GIT_TRACE_FSCACHE
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:40:21 -04:00
Karsten Blees
b3538309ae fscache: load directories only once
If multiple threads access a directory that is not yet in the cache, the
directory will be loaded by each thread. Only one of the results is added
to the cache, all others are leaked. This wastes performance and memory.

On cache miss, add a future object to the cache to indicate that the
directory is currently being loaded. Subsequent threads register themselves
with the future object and wait. When the first thread has loaded the
directory, it replaces the future object with the result and notifies
waiting threads.

Signed-off-by: Karsten Blees <blees@dcon.de>
2020-07-17 16:40:21 -04:00
Karsten Blees
656b86c6be mingw: add a cache below mingw's lstat and dirent implementations
Checking the work tree status is quite slow on Windows, due to slow
`lstat()` emulation (git calls `lstat()` once for each file in the
index). Windows operating system APIs seem to be much better at scanning
the status of entire directories than checking single files.

Add an `lstat()` implementation that uses a cache for lstat data. Cache
misses read the entire parent directory and add it to the cache.
Subsequent `lstat()` calls for the same directory are served directly
from the cache.

Also implement `opendir()`/`readdir()`/`closedir()` so that they create
and use directory listings in the cache.

The cache doesn't track file system changes and doesn't plug into any
modifying file APIs, so it has to be explicitly enabled for git functions
that don't modify the working copy.

Note: in an earlier version of this patch, the cache was always active and
tracked file system changes via ReadDirectoryChangesW. However, this was
much more complex and had negative impact on the performance of modifying
git commands such as 'git checkout'.

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:40:21 -04:00
Karsten Blees
60021bc9dd add infrastructure for read-only file system level caches
Add a macro to mark code sections that only read from the file system,
along with a config option and documentation.

This facilitates implementation of relatively simple file system level
caches without the need to synchronize with the file system.

Enable read-only sections for 'git status' and preload_index.

Signed-off-by: Karsten Blees <blees@dcon.de>
2020-07-17 16:40:20 -04:00
Karsten Blees
1cb69513ba Win32: make the lstat implementation pluggable
Emulating the POSIX lstat API on Windows via GetFileAttributes[Ex] is quite
slow. Windows operating system APIs seem to be much better at scanning the
status of entire directories than checking single files. A caching
implementation may improve performance by bulk-reading entire directories
or reusing data obtained via opendir / readdir.

Make the lstat implementation pluggable so that it can be switched at
runtime, e.g. based on a config option.

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:40:20 -04:00
Karsten Blees
2030b3cf0f mingw: make the dirent implementation pluggable
Emulating the POSIX `dirent` API on Windows via
`FindFirstFile()`/`FindNextFile()` is pretty staightforward, however,
most of the information provided in the `WIN32_FIND_DATA` structure is
thrown away in the process. A more sophisticated implementation may
cache this data, e.g. for later reuse in calls to `lstat()`.

Make the `dirent` implementation pluggable so that it can be switched at
runtime, e.g. based on a config option.

Define a base DIR structure with pointers to `readdir()`/`closedir()`
that match the `opendir()` implementation (similar to vtable pointers in
Object-Oriented Programming). Define `readdir()`/`closedir()` so that
they call the function pointers in the `DIR` structure. This allows to
choose the `opendir()` implementation on a call-by-call basis.

Make the fixed-size `dirent.d_name` buffer a flex array, as `d_name` may
be implementation specific (e.g. a caching implementation may allocate a
`struct dirent` with _just_ the size needed to hold the `d_name` in
question).

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:40:19 -04:00
Karsten Blees
c64923ac62 Win32: dirent.c: Move opendir down
Move opendir down in preparation for the next patch.

Signed-off-by: Karsten Blees <blees@dcon.de>
2020-07-17 16:40:19 -04:00
Karsten Blees
8685106fdf Win32: make FILETIME conversion functions public
We will use them in the upcoming "FSCache" patches (to accelerate
sequential lstat() calls).

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:40:19 -04:00
Johannes Schindelin
ec1b2bfd2e Merge pull request #2618 from dscho/avoid-d/f-conflict-in-vs/master
ci: avoid d/f conflict in vs/master
2020-07-17 16:40:10 -04:00
Jeff Hostetler
08c58585c1 Merge pull request #2589 from jeffhostetler/unlink-perf-gfw
mingw: improve performance of mingw_unlink()
2020-07-17 16:40:09 -04:00
Johannes Schindelin
4cda7c2082 Merge pull request #2549 from remybohmer/master
[fix] Gitk fails to open on a bare Git repository on Windows
2020-07-17 16:40:08 -04:00
Johannes Schindelin
52b0fff40b Merge pull request #2535 from dscho/schannel-revoke-best-effort
Introduce and use the new "best effort" strategy for Secure Channel revoke checking
2020-07-17 16:40:07 -04:00
Johannes Schindelin
977ae4f759 Merge pull request #2516 from nyckyta/crlf-aware-git-credential
credential.c: fix credential reading with regards to CR/LF
2020-07-17 16:40:07 -04:00
Johannes Schindelin
f811fe7388 Merge pull request #2506 from dscho/issue-2283
Allow running Git directly from `C:\Program Files\Git\mingw64\bin\git.exe`
2020-07-17 16:40:06 -04:00
Johannes Schindelin
4414088d80 Merge pull request #2504 from dscho/access-repo-via-junction
Handle `git add <file>` where <file> traverses an NTFS junction
2020-07-17 16:40:05 -04:00
Johannes Schindelin
3cce868394 Merge pull request #2501 from jeffhostetler/clink-debug-curl
clink.pl: fix MSVC compile script to handle libcurl-d.lib
2020-07-17 16:40:05 -04:00
Johannes Schindelin
d288c6860c Merge pull request #2488 from bmueller84/master
mingw: fix fatal error working on mapped network drives on Windows
2020-07-17 16:40:04 -04:00
Johannes Schindelin
cb7d48e5e0 Merge pull request #2449 from dscho/mingw-getcwd-and-symlinks
Do resolve symlinks in `getcwd()`
2020-07-17 16:40:03 -04:00
Johannes Schindelin
e509b376d7 Merge pull request #2405 from dscho/mingw-setsockopt
Make sure `errno` is set when socket operations fail
2020-07-17 16:40:02 -04:00
Johannes Schindelin
6714348040 Merge pull request #2375 from assarbad/reintroduce-sideband-config
Config option to disable side-band-64k for transport
2020-07-17 16:40:02 -04:00
Johannes Schindelin
1933a97422 Merge branch 'msys2-python'
In MSYS2, we have two Python interpreters at our disposal, so we can
include the Python stuff in the build.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:40:01 -04:00
Johannes Schindelin
751c97946e Merge branch 'move-gfw-system-config-to-top-level'
Make `git config --system` work like you think it should on Windows: it
should edit the file that is located in `<Git>\etc\gitconfig`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:40:00 -04:00
Johannes Schindelin
63dca98917 Merge pull request #2351 from PhilipOakley/vcpkg-tip
Vcpkg Install: detect lack of working Git, and note possible vcpkg time outs
2020-07-17 16:40:00 -04:00
Johannes Schindelin
8c0db63e01 Merge pull request #2316 from carenas/win-pcre1-cleanup
config.mak.uname: PCRE1 cleanup
2020-07-17 16:39:59 -04:00
Johannes Schindelin
52ca45b358 Merge branch 'dont-clean-junctions'
This topic branch teaches `git clean` to respect NTFS junctions and Unix
bind mounts: it will now stop at those boundaries.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:58 -04:00
Johannes Schindelin
a2a0f3e7fe Merge pull request #2170 from dscho/gitk-long-cmdline
Fix gitk (long cmdline)
2020-07-17 16:39:57 -04:00
Johannes Schindelin
47cd976333 Merge branch 'fsync-object-files-always'
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:56 -04:00
Johannes Schindelin
e8e94f4490 Merge branch 'dont-spawn-gzip-in-archive'
This topic branch avoids spawning `gzip` when asking `git archive` to
create `.tar.gz` files.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:56 -04:00
Johannes Schindelin
fe8c65f5c0 Merge branch 'mingw-expand-absolute-user-path'
When compiling Git with a runtime prefix (so that it can be installed
into any location, finding its libexec/ directory relative to the
location of the `git` executable), it is convenient to provide
"absolute" Unix-y paths e.g. for http.sslCAInfo, and have those absolute
paths be resolved relative to the runtime prefix.

This patch makes it so for Windows. It is up for discussion whether we
want this for other platforms, too, as long as building with
RUNTIME_PREFIX.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:55 -04:00
Johannes Schindelin
3679a3a722 Merge branch 'drive-prefix'
This topic branch allows us to specify absolute paths without the drive
prefix e.g. when cloning.

Example:

	C:\Users\me> git clone https://github.com/git/git \upstream-git

This will clone into a new directory C:\upstream-git, in line with how
Windows interprets absolute paths.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:54 -04:00
Johannes Schindelin
d17c417151 Merge pull request #996 from jeffhostetler/jeffhostetler/register_rename_src
diffcore-rename: speed up register_rename_src
2020-07-17 16:39:54 -04:00
Johannes Schindelin
cb3e81792d 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>
2020-07-17 16:39:53 -04:00
Johannes Schindelin
f1b1ed4ba8 t5505/t5516: fix white-space around redirectors
The convention in Git project's shell scripts is to have white-space
_before_, but not _after_ the `>` (or `<`).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:52 -04:00
Johannes Schindelin
760df631f0 t5505/t5516: allow running without .git/branches/ in the templates
When we commit the template directory as part of `make vcxproj`, the
`branches/` directory is not actually commited, as it is empty.

Two tests were not prepared for that situation.

This developer tried to get rid of the support for `.git/branches/` a
long time ago, but that effort did not bear fruit, so the best we can do
is work around in these here tests.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:52 -04:00
Jeff Hostetler
6f2208440c mingw: improve performance of mingw_unlink()
Update mingw_unlink() to first try to delete the file with existing
permissions before trying to force it.

Windows throws an error when trying to delete a read-only file.  The
mingw_unlink() compatibility wrapper always tries to _wchmod(666) the
file before calling _wunlink() to avoid that error.  However, since
most files in the worktree are already writable, this is usually
wasted effort.

Update mingw_unlink() to just call DeleteFileW() directly and if that
succeeds return.  If that fails, fall back into the existing code path
to update the permissions and use _wunlink() to get the existing
error code mapping.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:51 -04:00
Johannes Schindelin
fc4363c123 vcxproj: unclash project directories with build outputs
It already caused problems with the test suite that the directory
containing `git.vcxproj` is called the same as the Git executable
without its file extension: `./git` is ambiguous, it could refer both to
the directory `git/` as well as to `git.exe`.

Now there is one more problem: when our GitHub workflow runs on the
`vs/master` branch, it fails in all but the Windows builds, as they want
to write the file `git` but there is already a directory in the way.

Let's just go ahead and append `.proj` to all of those directories, e.g.
`git.proj/` instead of `git/`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:51 -04:00
Remy Bohmer
e545fdc8c4 [fix] Gitk fails to open on a bare Git repository on Windows
Running 'git rev-parse --show-toplevel' fails on a bare git repo.
This causes gitk to fail to startup.

Signed-off-by: Remy Bohmer <github@bohmer.net>
2020-07-17 16:39:50 -04:00
Johannes Schindelin
06fb0249df http: use new "best effort" strategy for Secure Channel revoke checking
The native Windows HTTPS backend is based on Secure Channel which lets
the caller decide how to handle revocation checking problems caused by
missing information in the certificate or offline CRL distribution
points.

Unfortunately, cURL chose to handle these problems differently than
OpenSSL by default: while OpenSSL happily ignores those problems
(essentially saying "¯\_(ツ)_/¯"), the Secure Channel backend will error
out instead.

As a remedy, the "no revoke" mode was introduced, which turns off
revocation checking altogether. This is a bit heavy-handed. We support
this via the `http.schannelCheckRevoke` setting.

In https://github.com/curl/curl/pull/4981, we contributed an opt-in
"best effort" strategy that emulates what OpenSSL seems to do.

In Git for Windows, we actually want this to be the default. This patch
makes it so, introducing it as a new value for the
`http.schannelCheckRevoke" setting, which now becmes a tristate: it
accepts the values "false", "true" or "best-effort" (defaulting to the
last one).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:50 -04:00
Nikita Leonov
79883a3c4e credential.c: fix credential reading with regards to CR/LF
This fix makes using Git credentials more friendly to Windows users. In
previous version it was unable to finish input correctly without
configuration changes (tested in PowerShell, CMD, Cygwin).

We know credential filling should be finished by empty input, but the
current implementation does not take into account CR/LF ending, and
hence instead of the empty string we get '\r', which is interpreted as
an incorrect string.

So this commit changes default reading function to a more Windows
compatible reading function.

Signed-off-by: Nikita Leonov <nykyta.leonov@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:49 -04:00
Johannes Schindelin
2e34bc16cc tests: exercise the RUNTIME_PREFIX feature
Originally, we refrained from adding a regression test in 7b6c649637
(system_path(): Add prefix computation at runtime if RUNTIME_PREFIX set,
2008-08-10), and in 226c0ddd0d (exec_cmd: RUNTIME_PREFIX on some POSIX
systems, 2018-04-10).

The reason was that it was deemed too tricky to test.

Turns out that it is not tricky to test at all: we simply create a
pseudo-root, copy the `git` executable into the `git/` subdirectory of
that pseudo-root, then copy a script into the `libexec/git-core/`
directory and expect that to be picked up.

As long as the trash directory is in a location where binaries can be
executed, this works.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:48 -04:00
Johannes Schindelin
a15356b826 mingw: allow git.exe to be used instead of the "Git wrapper"
Git for Windows wants to add `git.exe` to the users' `PATH`, without
cluttering the latter with unnecessary executables such as `wish.exe`.
To that end, it invented the concept of its "Git wrapper", i.e. a tiny
executable located in `C:\Program Files\Git\cmd\git.exe` (originally a
CMD script) whose sole purpose is to set up a couple of environment
variables and then spawn the _actual_ `git.exe` (which nowadays lives in
`C:\Program Files\Git\mingw64\bin\git.exe` for 64-bit, and the obvious
equivalent for 32-bit installations).

Currently, the following environment variables are set unless already
initialized:

- `MSYSTEM`, to make sure that the MSYS2 Bash and the MSYS2 Perl
  interpreter behave as expected, and

- `PLINK_PROTOCOL`, to force PuTTY's `plink.exe` to use the SSH
  protocol instead of Telnet,

- `PATH`, to make sure that the `bin` folder in the user's home
  directory, as well as the `/mingw64/bin` and the `/usr/bin`
  directories are included. The trick here is that the `/mingw64/bin/`
  and `/usr/bin/` directories are relative to the top-level installation
  directory of Git for Windows (which the included Bash interprets as
  `/`, i.e. as the MSYS pseudo root directory).

Using the absence of `MSYSTEM` as a tell-tale, we can detect in
`git.exe` whether these environment variables have been initialized
properly. Therefore we can call `C:\Program Files\Git\mingw64\bin\git`
in-place after this change, without having to call Git through the Git
wrapper.

Obviously, above-mentioned directories must be _prepended_ to the `PATH`
variable, otherwise we risk picking up executables from unrelated Git
installations. We do that by constructing the new `PATH` value from
scratch, appending `$HOME/bin` (if `HOME` is set), then the MSYS2 system
directories, and then appending the original `PATH`.

Side note: this modification of the `PATH` variable is independent of
the modification necessary to reach the executables and scripts in
`/mingw64/libexec/git-core/`, i.e. the `GIT_EXEC_PATH`. That
modification is still performed by Git, elsewhere, long after making the
changes described above.

While we _still_ cannot simply hard-link `mingw64\bin\git.exe` to `cmd`
(because the former depends on a couple of `.dll` files that are only in
`mingw64\bin`, i.e. calling `...\cmd\git.exe` would fail to load due to
missing dependencies), at least we can now avoid that extra process of
running the Git wrapper (which then has to wait for the spawned
`git.exe` to finish) by calling `...\mingw64\bin\git.exe` directly, via
its absolute path.

Testing this is in Git's test suite tricky: we set up a "new" MSYS
pseudo-root and copy the `git.exe` file into the appropriate location,
then verify that `MSYSTEM` is set properly, and also that the `PATH` is
modified so that scripts can be found in `$HOME/bin`, `/mingw64/bin/`
and `/usr/bin/`.

This addresses https://github.com/git-for-windows/git/issues/2283

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:48 -04:00
Johannes Schindelin
41d1d62628 mingw: ensure valid CTYPE
A change between versions 2.4.1 and 2.6.0 of the MSYS2 runtime modified
how Cygwin's runtime (and hence Git for Windows' MSYS2 runtime
derivative) handles locales: d16a56306d (Consolidate wctomb/mbtowc calls
for POSIX-1.2008, 2016-07-20).

An unintended side-effect is that "cold-calling" into the POSIX
emulation will start with a locale based on the current code page,
something that Git for Windows is very ill-prepared for, as it expects
to be able to pass a command-line containing non-ASCII characters to the
shell without having those characters munged.

One symptom of this behavior: when `git clone` or `git fetch` shell out
to call `git-upload-pack` with a path that contains non-ASCII
characters, the shell tried to interpret the entire command-line
(including command-line parameters) as executable path, which obviously
must fail.

This fixes https://github.com/git-for-windows/git/issues/1036

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:48 -04:00
Johannes Schindelin
b836422a7f mingw: implement a platform-specific strbuf_realpath()
There is a Win32 API function to resolve symbolic links, and we can use
that instead of resolving them manually. Even better, this function also
resolves NTFS junction points (which are somewhat similar to bind
mounts).

This fixes https://github.com/git-for-windows/git/issues/2481.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:47 -04:00
Johannes Schindelin
2a6735145d strbuf_realpath(): use platform-dependent API if available
Some platforms (e.g. Windows) provide API functions to resolve paths
much quicker. Let's offer a way to short-cut `strbuf_realpath()` on
those platforms.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:47 -04:00
Jeff Hostetler
c0ad80c534 clink.pl: fix MSVC compile script to handle libcurl-d.lib
Update clink.pl to link with either libcurl.lib or libcurl-d.lib
depending on whether DEBUG=1 is set.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:46 -04:00
Johannes Schindelin
cce290ef54 mingw: demonstrate a git add issue with NTFS junctions
NTFS junctions are somewhat similar in spirit to Unix bind mounts: they
point to a different directory and are resolved by the filesystem
driver. As such, they appear to `lstat()` as if they are directories,
not as if they are symbolic links.

_Any_ user can create junctions, while symbolic links can only be
created by non-administrators in Developer Mode on Windows 10. Hence
NTFS junctions are much more common "in the wild" than NTFS symbolic
links.

It was reported in https://github.com/git-for-windows/git/issues/2481
that adding files via an absolute path that traverses an NTFS junction:
since 1e64d18 (mingw: do resolve symlinks in `getcwd()`), we resolve not
only symbolic links but also NTFS junctions when determining the
absolute path of the current directory. The same is not true for `git
add <file>`, where symbolic links are resolved in `<file>`, but not NTFS
junctions.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-07-17 16:39:46 -04:00