We already have a directory where we store files intended for use by
multiple test scripts. The same directory is a better home for the
test-binary-*.png files than t/.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
It is convenient to assume that everybody who wants to build & test Git
has access to a working `iconv` executable (after all, we already pretty
much require libiconv).
However, that limits esoteric test scenarios such as Git for Windows',
where an end user installation has to ship with `iconv` for the sole
purpose of being testable. That payload serves no other purpose.
So let's just have a test helper (to be able to test Git, the test
helpers have to be available, after all) to act as `iconv` replacement.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
It is a bit strange, and even undesirable, to require Perl just to run
the test suite even when NO_PERL was set.
This patch does not fix this problem by any stretch of imagination.
However, it fixes *the* Perl invocation that *every single* test script
has to run.
While at it, it makes the source code also more grep'able, as the code
that unsets some, but not all, GIT_* environment variables just became a
*lot* more explicit. And all that while still reducing the total number
of lines.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
BusyBox comes with a ton of applets ("applet" being the identical
concept to Git's "builtins"). And similar to Git's builtins, the applets
can be called via `busybox <command>`, or the BusyBox executable can be
copied/hard-linked to the command name.
The similarities do not end here. Just as with Git's builtins, it is
problematic that BusyBox' hard-linked applets cannot easily be put into
a .zip file: .zip archives have no concept of hard-links and therefore
would store identical copies (and also extract identical copies,
"inflating" the archive unnecessarily).
To counteract that issue, MinGit already ships without hard-linked
copies of the builtins, and the plan is to do the same with BusyBox'
applets: simply ship busybox.exe as single executable, without
hard-linked applets.
To accommodate that, Git is being taught by this commit a very special
trick, exploiting the fact that it is possible to call an executable
with a command-line whose argv[0] is different from the executable's
name: when `sh` is to be spawned, and no `sh` is found in the PATH, but
busybox.exe is, use that executable (with unchanged argv).
Likewise, if any executable to be spawned is not on the PATH, but
busybox.exe is found, parse the output of `busybox.exe --help` to find
out what applets are included, and if the command matches an included
applet name, use busybox.exe to execute it.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
To verify that the symlink is resolved correctly, we use the fact that
`git.exe` is a native Win32 program, and that `git.exe config -f <path>`
therefore uses the native symlink resolution.
Signed-off-by: Bert Belder <bertbelder@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
With the recent update in efee955 (gpg-interface: check gpg signature
creation status, 2016-06-17), we ask GPG to send all status updates to
stderr, and then catch the stderr in an strbuf.
But GPG might fail, and send error messages to stderr. And we simply
do not show them to the user.
Even worse: this swallows any interactive prompt for a passphrase. And
detaches stderr from the tty so that the passphrase cannot be read.
So while the first problem could be fixed (by printing the captured
stderr upon error), the second problem cannot be easily fixed, and
presents a major regression.
So let's just revert commit efee9553a4.
This fixes https://github.com/git-for-windows/git/issues/871
Cc: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Windows paths are typically limited to MAX_PATH = 260 characters, even
though the underlying NTFS file system supports paths up to 32,767 chars.
This limitation is also evident in Windows Explorer, cmd.exe and many
other applications (including IDEs).
Particularly annoying is that most Windows APIs return bogus error codes
if a relative path only barely exceeds MAX_PATH in conjunction with the
current directory, e.g. ERROR_PATH_NOT_FOUND / ENOENT instead of the
infinitely more helpful ERROR_FILENAME_EXCED_RANGE / ENAMETOOLONG.
Many Windows wide char APIs support longer than MAX_PATH paths through the
file namespace prefix ('\\?\' or '\\?\UNC\') followed by an absolute path.
Notable exceptions include functions dealing with executables and the
current directory (CreateProcess, LoadLibrary, Get/SetCurrentDirectory) as
well as the entire shell API (ShellExecute, SHGetSpecialFolderPath...).
Introduce a handle_long_path function to check the length of a specified
path properly (and fail with ENAMETOOLONG), and to optionally expand long
paths using the '\\?\' file namespace prefix. Short paths will not be
modified, so we don't need to worry about device names (NUL, CON, AUX).
Contrary to MSDN docs, the GetFullPathNameW function doesn't seem to be
limited to MAX_PATH (at least not on Win7), so we can use it to do the
heavy lifting of the conversion (translate '/' to '\', eliminate '.' and
'..', and make an absolute path).
Add long path error checking to xutftowcs_path for APIs with hard MAX_PATH
limit.
Add a new MAX_LONG_PATH constant and xutftowcs_long_path function for APIs
that support long paths.
While improved error checking is always active, long paths support must be
explicitly enabled via 'core.longpaths' option. This is to prevent end
users to shoot themselves in the foot by checking out files that Windows
Explorer, cmd/bash or their favorite IDE cannot handle.
Test suite:
Test the case is when the full pathname length of a dir is close
to 260 (MAX_PATH).
Bug report and an original reproducer by Andrey Rogozhnikov:
https://github.com/msysgit/git/pull/122#issuecomment-43604199
[jes: adjusted test number to avoid conflicts, added support for
chdir(), etc]
Thanks-to: Martin W. Kirst <maki@bitkings.de>
Thanks-to: Doug Kelly <dougk.ff7@gmail.com>
Original-test-by: Andrey Rogozhnikov <rogozhnikov.andrey@gmail.com>
Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Stepan Kasal <kasal@ucw.cz>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
There is a problem in the way 9ac3f0e5b3 (pack-objects: fix
performance issues on packing large deltas, 2018-07-22) initializes that
mutex in the `packing_data` struct. The problem manifests in a
segmentation fault on Windows, when a mutex (AKA critical section) is
accessed without being initialized. (With pthreads, you apparently do
not really have to initialize them?)
This was reported in https://github.com/git-for-windows/git/issues/1839.
Signed-off-by: Doug Kelly <dougk.ff7@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This is retry of #1419.
I added flush_fscache macro to flush cached stats after disk writing
with tests for regression reported in #1438 and #1442.
git checkout checks each file path in sorted order, so cache flushing does not
make performance worse unless we have large number of modified files in
a directory containing many files.
Using chromium repository, I tested `git checkout .` performance when I
delete 10 files in different directories.
With this patch:
TotalSeconds: 4.307272
TotalSeconds: 4.4863595
TotalSeconds: 4.2975562
Avg: 4.36372923333333
Without this patch:
TotalSeconds: 20.9705431
TotalSeconds: 22.4867685
TotalSeconds: 18.8968292
Avg: 20.7847136
I confirmed this patch passed all tests in t/ with core_fscache=1.
Signed-off-by: Takuto Ikuta <tikuta@chromium.org>
This topic branch allows `add -p` and `add -i` with a large number of
files. It is kind of a hack that was never really meant to be
upstreamed. Let's see if we can do better in the built-in `add -p`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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>
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>
To verify that the `clean` side of the `clean`/`smudge` filter code is
correct with regards to LLP64 (read: to ensure that `size_t` is used
instead of `unsigned long`), here is a test case using a trivial filter,
specifically _not_ writing anything to the object store to limit the
scope of the test case.
As in previous commits, the `big` file from previous test cases is
reused if available, to save setup time, otherwise re-generated.
Signed-off-by: Philip Oakley <philipoakley@iee.email>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
To complement the `--stdin` and `--literally` test cases that verify
that we can hash files larger than 4GB on 64-bit platforms using the
LLP64 data model, here is a test case that exercises `hash-object`
_without_ any options.
Just as before, we use the `big` file from the previous test case if it
exists to save on setup time, otherwise generate it.
Signed-off-by: Philip Oakley <philipoakley@iee.email>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Just like the `hash-object --literally` code path, the `--stdin` code
path also needs to use `size_t` instead of `unsigned long` to represent
memory sizes, otherwise it would cause problems on platforms using the
LLP64 data model (such as Windows).
To limit the scope of the test case, the object is explicitly not
written to the object store, nor are any filters applied.
The `big` file from the previous test case is reused to save setup time;
To avoid relying on that side effect, it is generated if it does not
exist (e.g. when running via `sh t1007-*.sh --long --run=1,41`).
Signed-off-by: Philip Oakley <philipoakley@iee.email>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Continue walking the code path for the >4GB `hash-object --literally`
test to the hash algorithm step for LLP64 systems.
This patch lets the SHA1DC code use `size_t`, making it compatible with
LLP64 data models (as used e.g. by Windows).
The interested reader of this patch will note that we adjust the
signature of the `git_SHA1DCUpdate()` function without updating _any_
call site. This certainly puzzled at least one reviewer already, so here
is an explanation:
This function is never called directly, but always via the macro
`platform_SHA1_Update`, which is usually called via the macro
`git_SHA1_Update`. However, we never call `git_SHA1_Update()` directly
in `struct git_hash_algo`. Instead, we call `git_hash_sha1_update()`,
which is defined thusly:
static void git_hash_sha1_update(git_hash_ctx *ctx,
const void *data, size_t len)
{
git_SHA1_Update(&ctx->sha1, data, len);
}
i.e. it contains an implicit downcast from `size_t` to `unsigned long`
(before this here patch). With this patch, there is no downcast anymore.
With this patch, finally, the t1007-hash-object.sh "files over 4GB hash
literally" test case is fixed.
Signed-off-by: Philip Oakley <philipoakley@iee.email>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
On LLP64 systems, such as Windows, the size of `long`, `int`, etc. is
only 32 bits (for backward compatibility). Git's use of `unsigned long`
for file memory sizes in many places, rather than size_t, limits the
handling of large files on LLP64 systems (commonly given as `>4GB`).
Provide a minimum test for handling a >4GB file. The `hash-object`
command, with the `--literally` and without `-w` option avoids
writing the object, either loose or packed. This avoids the code paths
hitting the `bigFileThreshold` config test code, the zlib code, and the
pack code.
Subsequent patches will walk the test's call chain, converting types to
`size_t` (which is larger in LLP64 data models) where appropriate.
Signed-off-by: Philip Oakley <philipoakley@iee.email>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
For some reason, this test case was indented with 4 spaces instead of 1
horizontal tab. The other test cases in the same test script are fine.
Signed-off-by: Jens Glathe <jens.glathe@oldschoolsolutions.biz>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This change enhances `git commit --cleanup=scissors` by detecting
scissors lines ending in either LF (UNIX-style) or CR/LF (DOS-style).
Regression tests are included to specifically test for trailing
comments after a CR/LF-terminated scissors line.
Signed-off-by: Luke Bonanomi <lbonanomi@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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>
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>
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>
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>
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>
Windows' equivalent to "bind mounts", NTFS junction points, can be
unlinked without affecting the mount target. This is clearly what users
expect to happen when they call `git clean -dfx` in a worktree that
contains NTFS junction points: the junction should be removed, and the
target directory of said junction should be left alone (unless it is
inside the worktree).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
When specifying an absolute path without a drive prefix, we convert that
path internally. Let's make sure that we handle that case properly, too
;-)
This fixes the command
git clone https://github.com/git-for-windows/git \G4W
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
It seems to be not exactly rare on Windows to install NTFS junction
points (the equivalent of "bind mounts" on Linux/Unix) in worktrees,
e.g. to map some development tools into a subdirectory.
In such a scenario, it is pretty horrible if `git clean -dfx` traverses
into the mapped directory and starts to "clean up".
Let's just not do that. Let's make sure before we traverse into a
directory that it is not a mount point (or junction).
This addresses https://github.com/git-for-windows/git/issues/607
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
On Windows, there are several categories of absolute paths. One such
category starts with a backslash and is implicitly relative to the
drive associated with the current working directory. Example:
c:
git clone https://github.com/git-for-windows/git \G4W
should clone into C:\G4W.
There is currently a problem with that, in that mingw_mktemp() does not
expect the _wmktemp() function to prefix the absolute path with the
drive prefix, and as a consequence, the resulting path does not fit into
the originally-passed string buffer. The symptom is a "Result too large"
error.
Reported by Juan Carlos Arevalo Baeza.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This happens only when the corresponding commits are not exported in
the current fast-export run. This can happen either when the relevant
commit is already marked, or when the commit is explicitly marked
as UNINTERESTING with a negative ref by another argument.
This breaks fast-export basec remote helpers.
Signed-off-by: Sverre Rabbelier <srabbelier@gmail.com>
We started unconditionally testing with CGIPassAuth directive but
it is unavailable in older Apache that ships with CentOS 7 that has
about a year of shelf-life still left. The test has conditionally
been disabled when running with an ancient Apache. This was a fix
for a recent regression caught before the release, so no need to
mention it in the release notes.
* jk/http-test-cgipassauth-unavailable-in-older-apache:
t/lib-httpd: make CGIPassAuth support conditional
The server side of "git clone" now advertises the necessary hints
to clients to help them to clone from an empty repository and learn
object hash algorithm and the (unborn) branch pointed at by HEAD,
even over the older v0/v1 protocol.
* bc/clone-empty-repo-via-protocol-v0:
upload-pack: advertise capabilities when cloning empty repos
When "git send-email" that uses the validate hook is fed a message
without and then with Message-ID, it failed to auto-assign a unique
Message-ID to the former and instead reused the Message-ID from the
latter, which has been corrected. This was a fix for a recent
regression caught before the release, so no need to mention it in
the release notes.
* jc/send-email-pre-process-fix:
t9001: mark the script as no longer leak checker clean
send-email: clear the $message_id after validation
Commit 988aad99b4 (t5563: add tests for basic and anoymous HTTP access,
2023-02-27) added tests that require Apache to support the CGIPassAuth
directive, which was added in Apache 2.4.13. This is fairly old (~8
years), but recent enough that we still encounter it in the wild (e.g.,
RHEL/CentOS 7, which is not EOL until June 2024).
We can live with skipping the new tests on such a platform. But
unfortunately, since the directive is used unconditionally in our
apache.conf, it means the web server fails to start entirely, and we
cannot run other HTTP tests at all (e.g., the basic ones in t5551).
We can fix that by making the config conditional, and only triggering it
for t5563. That solves the problem for t5551 (which then ignores the
directive entirely). For t5563, we'd see apache complain in start_httpd;
with the default setting of GIT_TEST_HTTPD, we'd then skip the whole
script.
But that leaves one small problem: people may set GIT_TEST_HTTPD=1
explicitly, which instructs the tests to fail (rather than skip) when we
can't start the webserver (to avoid accidentally missing some tests).
This could be worked around by having the user manually set
GIT_SKIP_TESTS on a platform with an older Apache. But we can be a bit
friendlier by doing the version check ourselves and setting an
appropriate prereq. We'll use the (lack of) prereq to then skip the rest
of t5563. In theory we could use the prereq to skip individual tests, but
in practice this whole script depends on it.
Reported-by: Todd Zullinger <tmz@pobox.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The test uses "format-patch --thread" which is known to leak the
generated message ID list.
Plugging these leaks involves straightening out the memory ownership
rules around rev_info.message_id and rev_info.ref_message_ids, and
is beyond the scope of send-email fix, so for now mark the test as
leaky to unblock the topic before the release.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Recently git-send-email started parsing the same message twice, once
to validate _all_ the message before sending even the first one, and
then after the validation hook is happy and each message gets sent,
to read the contents to find out where to send to etc.
Unfortunately, the effect of reading the messages for validation
lingered even after the validation is done. Namely $message_id gets
assigned if exists in the input files but the variable is global,
and it is not cleared before pre_process_file runs. This causes
reading a message without a message-id followed by reading a message
with a message-id to misbehave---the sub reports as if the message
had the same id as the previously written one.
Clear the variable before starting to read the headers in
pre_process_file.
Tested-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When cloning an empty repository, protocol versions 0 and 1 currently
offer nothing but the header and flush packets for the /info/refs
endpoint. This means that no capabilities are provided, so the client
side doesn't know what capabilities are present.
However, this does pose a problem when working with SHA-256
repositories, since we use the capabilities to know the remote side's
object format (hash algorithm). As of 8b214c2e9d ("clone: propagate
object-format when cloning from void", 2023-04-05), this has been fixed
for protocol v2, since there we always read the hash algorithm from the
remote.
Fortunately, the push version of the protocol already indicates a clue
for how to solve this. When the /info/refs endpoint is accessed for a
push and the remote is empty, we include a dummy "capabilities^{}" ref
pointing to the all-zeros object ID. The protocol documentation already
indicates this should _always_ be sent, even for fetches and clones, so
let's just do that, which means we'll properly announce the hash
algorithm as part of the capabilities. This just works with the
existing code because we share the same ref code for fetches and clones,
and libgit2, JGit, and dulwich do as well.
There is one minor issue to fix, though. If we called send_ref with
namespaces, we would return NULL with the capabilities entry, which
would cause a crash. Instead, let's refactor out a function to print
just the ref itself without stripping the namespace and use it for our
special capabilities entry.
Add several sets of tests for HTTP as well as for local clones. The
behavior can be slightly different for HTTP versus a local or SSH clone
because of the stateless-rpc functionality, so it's worth testing both.
Signed-off-by: brian m. carlson <bk2204@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git --attr-source=<tree> cmd $args" is a new way to have any
command to read attributes not from the working tree but from the
given tree object.
* jc/attr-source-tree:
attr: teach "--attr-source=<tree>" global option to "git"
"git fetch" learned the "--porcelain" option that emits what it did
in a machine-parseable format.
* ps/fetch-output-format:
fetch: introduce machine-parseable "porcelain" output format
fetch: move option related variables into main function
fetch: lift up parsing of "fetch.output" config variable
fetch: introduce `display_format` enum
fetch: refactor calculation of the display table width
fetch: print left-hand side when fetching HEAD:foo
fetch: add a test to exercise invalid output formats
fetch: split out tests for output format
fetch: fix `--no-recurse-submodules` with multi-remote fetches
Teach "diff-files" not to expand sparse-index unless needed.
* sl/diff-files-sparse:
diff-files: integrate with sparse index
t1092: add tests for `git diff-files`
