Commit Graph

107363 Commits

Author SHA1 Message Date
Jeff Hostetler
b59d2a5aed fscache: add key for GIT_TRACE_FSCACHE
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-03-06 08:03:13 +01:00
Karsten Blees
0b069e0074 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>
2020-03-06 08:03:13 +01:00
Karsten Blees
58faee0a91 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>
2020-03-06 08:03:13 +01:00
Karsten Blees
c6eccfc2c2 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>
2020-03-06 08:03:12 +01:00
Karsten Blees
f10716000e 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>
2020-03-06 08:03:12 +01:00
Karsten Blees
ae8ae3832c 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>
2020-03-06 08:03:12 +01:00
Karsten Blees
d5f86f9feb Win32: dirent.c: Move opendir down
Move opendir down in preparation for the next patch.

Signed-off-by: Karsten Blees <blees@dcon.de>
2020-03-06 08:03:12 +01:00
Karsten Blees
5aadf8943e 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>
2020-03-06 08:03:12 +01:00
Johannes Schindelin
b469972d94 Merge pull request #2535 from dscho/schannel-revoke-best-effort
Introduce and use the new "best effort" strategy for Secure Channel revoke checking
2020-03-06 08:03:08 +01:00
Johannes Schindelin
ee83aaa5d1 Merge pull request #2516 from nyckyta/crlf-aware-git-credential
credential.c: fix credential reading with regards to CR/LF
2020-03-06 08:03:07 +01:00
Johannes Schindelin
22e5c4fc95 Merge pull request #2506 from dscho/issue-2283
Allow running Git directly from `C:\Program Files\Git\mingw64\bin\git.exe`
2020-03-06 08:03:06 +01:00
Johannes Schindelin
9753d533d2 Merge pull request #2504 from dscho/access-repo-via-junction
Handle `git add <file>` where <file> traverses an NTFS junction
2020-03-06 08:03:05 +01:00
Johannes Schindelin
91573cd503 Merge pull request #2501 from jeffhostetler/clink-debug-curl
clink.pl: fix MSVC compile script to handle libcurl-d.lib
2020-03-06 08:03:05 +01:00
Johannes Schindelin
edd36ae726 Merge pull request #2488 from bmueller84/master
mingw: fix fatal error working on mapped network drives on Windows
2020-03-06 08:03:04 +01:00
Johannes Schindelin
0229ef99a0 Merge pull request #2473 from dscho/com0-is-not-a-reserved-name
Do not mistake `COM0` for a reserved file name
2020-03-06 08:03:03 +01:00
Johannes Schindelin
bab7ffe864 Merge pull request #2449 from dscho/mingw-getcwd-and-symlinks
Do resolve symlinks in `getcwd()`
2020-03-06 08:03:02 +01:00
Johannes Schindelin
cd75e70023 Merge pull request #2405 from dscho/mingw-setsockopt
Make sure `errno` is set when socket operations fail
2020-03-06 08:03:02 +01:00
Johannes Schindelin
a232734cc5 Merge pull request #2375 from assarbad/reintroduce-sideband-config
Config option to disable side-band-64k for transport
2020-03-06 08:03:01 +01:00
Johannes Schindelin
68542ddf57 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>
2020-03-06 08:03:01 +01:00
Johannes Schindelin
c6e18e46d1 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>
2020-03-06 08:03:00 +01:00
Johannes Schindelin
5b5b923167 Merge pull request #2351 from PhilipOakley/vcpkg-tip
Vcpkg Install: detect lack of working Git, and note possible vcpkg time outs
2020-03-06 08:02:59 +01:00
Johannes Schindelin
27cebfc284 Merge pull request #2316 from carenas/win-pcre1-cleanup
config.mak.uname: PCRE1 cleanup
2020-03-06 08:02:58 +01:00
Johannes Schindelin
6a0d791402 Merge branch 'work-around-isilon'
It would appear that least the Isilon network filesystem (and possibly
other network filesystems, too), report non-standard error values when
trying to access a non-existing directory.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-03-06 08:02:58 +01:00
Johannes Schindelin
387af0860e 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>
2020-03-06 08:02:57 +01:00
Johannes Schindelin
d781b4bec6 Merge branch 'msys2-strace'
Debugging support on MSYS2.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-03-06 08:02:56 +01:00
Johannes Schindelin
c3e7dc4630 Merge branch 'robustify-is-hidden-tests'
In Git for Windows, there is an option to mark the .git directory as
hidden. Our test cases verify this by using the system utility
`attrib.exe`.

This file name is unfortunately quite generic, and overlaps with a
Unix-y utility that might be hiding the system one in the `PATH`.

Let's specify explicitly which `attrib` to use.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-03-06 08:02:55 +01:00
Johannes Schindelin
dae0d80345 Merge branch 'fflush-in-git-clean'
After writing to `stdout` and before reading from `stdin`, it is a good
idea to flush the former.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-03-06 08:02:55 +01:00
Johannes Schindelin
13539237f5 Merge pull request #2170 from dscho/gitk-long-cmdline
Fix gitk (long cmdline)
2020-03-06 08:02:54 +01:00
Johannes Schindelin
50b6ea6d78 Merge branch 'fsync-object-files-always'
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-03-06 08:02:54 +01:00
Johannes Schindelin
40d496f4d3 Merge remote-tracking branch 'dscho/add-p' into add-p-g4w
Let's test this for a while.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-03-06 08:02:53 +01:00
Johannes Schindelin
bbf4fa574c Merge branch 'stash-p-corner-case'
This topic branch fixes a corner case that is amazingly common in this
developer's workflow: in a `git stash -p`, splitting a hunk and stashing
only part of it runs into a (known) bug where the partial hunk cannot be
applied in reverse.

It is one of those "good enough" fixes, not a full fix, though, as the
full fix would require a 3-way merge between `stash^` and the *worktree*
(not `HEAD`), with `stash` as merge base (i.e. a `git revert`, but on
top of the current worktree).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-03-06 08:02:45 +01:00
Johannes Schindelin
1def0ee711 stash -p: (partially) fix bug concerning split hunks
When trying to stash part of the worktree changes by splitting a hunk
and then only partially accepting the split bits and pieces, the user
is presented with a rather cryptic error:

	error: patch failed: <file>:<line>
	error: test: patch does not apply
	Cannot remove worktree changes

and the command would fail to stash the desired parts of the worktree
changes (even if the `stash` ref was actually updated correctly).

We even have a test case demonstrating that failure, carrying it for
four years already.

The explanation: when splitting a hunk, the changed lines are no longer
separated by more than 3 lines (which is the amount of context lines
Git's diffs use by default), but less than that. So when staging only
part of the diff hunk for stashing, the resulting diff that we want to
apply to the worktree in reverse will contain those changes to be
dropped surrounded by three context lines, but since the diff is
relative to HEAD rather than to the worktree, these context lines will
not match.

Example time. Let's assume that the file README contains these lines:

	We
	the
	people

and the worktree added some lines so that it contains these lines
instead:

	We
	are
	the
	kind
	people

and the user tries to stash the line containing "are", then the command
will internally stage this line to a temporary index file and try to
revert the diff between HEAD and that index file. The diff hunk that
`git stash` tries to revert will look somewhat like this:

	@@ -1776,3 +1776,4
	 We
	+are
	 the
	 people

It is obvious, now, that the trailing context lines overlap with the
part of the original diff hunk that the user did *not* want to stash.

Keeping in mind that context lines in diffs serve the primary purpose of
finding the exact location when the diff does not apply precisely (but
when the exact line number in the file to be patched differs from the
line number indicated in the diff), we work around this by reducing the
amount of context lines: the diff was just generated.

Note: this is not a *full* fix for the issue. Just as demonstrated in
t3701's 'add -p works with pathological context lines' test case, there
are ambiguities in the diff format. It is very rare in practice, of
course, to encounter such repeated lines.

The full solution for such cases would be to replace the approach of
generating a diff from the stash and then applying it in reverse by
emulating `git revert` (i.e. doing a 3-way merge). However, in `git
stash -p` it would not apply to `HEAD` but instead to the worktree,
which makes this non-trivial to implement as long as we also maintain a
scripted version of `add -i`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-03-06 08:02:44 +01:00
Johannes Schindelin
ddfd67b62e t3904: fix incorrect demonstration of a bug
In 7e9e048661 (stash -p: demonstrate failure of split with mixed y/n,
2015-04-16), a regression test for a known breakage that was added to
the test script `t3904-stash-patch.sh` that demonstrated that splitting
a hunk and trying to stash only part of that split hunk fails (but
shouldn't).

As expected, it still fails, but for the wrong reason: once the bug is
fixed, we would expect stderr to show nothing, yet the regression test
expects stderr to show something.

Let's fix that by telling that regression test case to expect nothing to
be printed to stderr.

While at it, also drop the obvious left-over from debugging where the
regression test did not mind `git stash -p` to return a non-zero exit
status.

Of course, the regression test still fails, but this time for the
correct reason.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-03-06 08:02:44 +01:00
Johannes Schindelin
c989bc5ec7 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>
2020-03-06 07:57:39 +01:00
Johannes Schindelin
ab6268ec56 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>
2020-03-06 07:57:38 +01:00
Johannes Schindelin
362cd7b78e 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>
2020-03-06 07:57:37 +01:00
Johannes Schindelin
f1d6a2589d Merge pull request #996 from jeffhostetler/jeffhostetler/register_rename_src
diffcore-rename: speed up register_rename_src
2020-03-06 07:57:36 +01:00
Johannes Schindelin
94ef09c5b8 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>
2020-03-06 07:57:36 +01:00
Johannes Schindelin
054b46f0a3 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>
2020-03-06 07:49:37 +01:00
Nikita Leonov
c46851fdff 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>
2020-03-06 07:49:37 +01:00
Johannes Schindelin
5b8a1168dd 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>
2020-03-06 07:49:37 +01:00
Johannes Schindelin
19ad6183b6 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>
2020-03-06 07:49:37 +01:00
Johannes Schindelin
db0462cd67 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>
2020-03-06 07:49:37 +01:00
Johannes Schindelin
b41023baa4 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>
2020-03-06 07:49:36 +01:00
Jeff Hostetler
9efe23df3a 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>
2020-03-06 07:49:36 +01:00
Bjoern Mueller
0ac1782838 mingw: fix fatal error working on mapped network drives on Windows
In 1e64d18 (mingw: do resolve symlinks in `getcwd()`) a problem was
introduced that causes git for Windows to stop working with certain
mapped network drives (in particular, drives that are mapped to
locations with long path names). Error message was "fatal: Unable to
read current working directory: No such file or directory". Present
change fixes this issue as discussed in
https://github.com/git-for-windows/git/issues/2480

Signed-off-by: Bjoern Mueller <bjoernm@gmx.de>
2020-03-06 07:49:36 +01:00
Johannes Schindelin
18e5a175e6 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>
2020-03-06 07:49:36 +01:00
Johannes Schindelin
4a7138b2bf 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>
2020-03-06 07:49:36 +01:00
Johannes Schindelin
cebc4c5f94 mingw: do not treat COM0 as a reserved file name
In 4dc42c6c18 (mingw: refuse paths containing reserved names,
2019-12-21), we started disallowing file names that are reserved, e.g.
`NUL`, `CONOUT$`, etc.

This included `COM<n>` where `<n>` is a digit. Unfortunately, this
includes `COM0` but only `COM1`, ..., `COM9` are reserved, according to
the official documentation, `COM0` is mentioned in the "NT Namespaces"
section but it is explicitly _omitted_ from the list of reserved names:
https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file#naming-conventions

Tests corroborate this: it is totally possible to write a file called
`com0.c` on Windows 10, but not `com1.c`.

So let's tighten the code to disallow only the reserved `COM<n>` file
names, but to allow `COM0` again.

This fixes https://github.com/git-for-windows/git/issues/2470.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-03-06 07:49:35 +01:00
Johannes Schindelin
8d9433f097 mingw: do resolve symlinks in getcwd()
As pointed out in https://github.com/git-for-windows/git/issues/1676,
the `git rev-parse --is-inside-work-tree` command currently fails when
the current directory's path contains symbolic links.

The underlying reason for this bug is that `getcwd()` is supposed to
resolve symbolic links, but our `mingw_getcwd()` implementation did not.

We do have all the building blocks for that, though: the
`GetFinalPathByHandleW()` function will resolve symbolic links. However,
we only called that function if `GetLongPathNameW()` failed, for
historical reasons: the latter function was supported for a long time,
but the former API function was introduced only with Windows Vista, and
we used to support also Windows XP. With that support having been
dropped, we are free to call the symbolic link-resolving function right
away.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2020-03-06 07:49:35 +01:00