Commit Graph

67290 Commits

Author SHA1 Message Date
Junio C Hamano
5a10f4c3a1 Merge branch 'jc/t6424-failing-merge-preserve-local-changes'
The tests that ensured merges stop when interfering local changes
are present did not make sure that local changes are preserved; now
they do.

* jc/t6424-failing-merge-preserve-local-changes:
  t6424: make sure a failed merge preserves local changes
2022-05-30 23:24:03 -07:00
Junio C Hamano
60be29398a Merge branch 'cc/http-curlopt-resolve'
With the new http.curloptResolve configuration, the CURLOPT_RESOLVE
mechanism that allows cURL based applications to use pre-resolved
IP addresses for the requests is exposed to the scripts.

* cc/http-curlopt-resolve:
  http: add custom hostname to IP address resolutions
2022-05-30 23:24:02 -07:00
Matthew John Cheetham
15d8adccab scalar: teach diagnose to gather loose objects information
When operating at the scale that Scalar wants to support, certain data
shapes are more likely to cause undesirable performance issues, such as
large numbers of loose objects.

By including statistics about this, `scalar diagnose` now makes it
easier to identify such scenarios.

Signed-off-by: Matthew John Cheetham <mjcheetham@outlook.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-30 23:07:31 -07:00
Matthew John Cheetham
93e804b278 scalar: teach diagnose to gather packfile info
It's helpful to see if there are other crud files in the pack
directory. Let's teach the `scalar diagnose` command to gather
file size information about pack files.

While at it, also enumerate the pack files in the alternate
object directories, if any are registered.

Signed-off-by: Matthew John Cheetham <mjcheetham@outlook.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-30 23:07:31 -07:00
Johannes Schindelin
0ed5b13f24 scalar diagnose: include disk space information
When analyzing problems with large worktrees/repositories, it is useful
to know how close to a "full disk" situation Scalar/Git operates. Let's
include this information.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-30 23:07:31 -07:00
Johannes Schindelin
aa5c79a331 scalar: implement scalar diagnose
Over the course of Scalar's development, it became obvious that there is
a need for a command that can gather all kinds of useful information
that can help identify the most typical problems with large
worktrees/repositories.

The `diagnose` command is the culmination of this hard-won knowledge: it
gathers the installed hooks, the config, a couple statistics describing
the data shape, among other pieces of information, and then wraps
everything up in a tidy, neat `.zip` archive.

Note: originally, Scalar was implemented in C# using the .NET API, where
we had the luxury of a comprehensive standard library that includes
basic functionality such as writing a `.zip` file. In the C version, we
lack such a commodity. Rather than introducing a dependency on, say,
libzip, we slightly abuse Git's `archive` machinery: we write out a
`.zip` of the empty try, augmented by a couple files that are added via
the `--add-file*` options. We are careful trying not to modify the
current repository in any way lest the very circumstances that required
`scalar diagnose` to be run are changed by the `diagnose` run itself.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-30 23:07:31 -07:00
Johannes Schindelin
b44855743b scalar: validate the optional enlistment argument
The `scalar` command needs a Scalar enlistment for many subcommands, and
looks in the current directory for such an enlistment (traversing the
parent directories until it finds one).

These is subcommands can also be called with an optional argument
specifying the enlistment. Here, too, we traverse parent directories as
needed, until we find an enlistment.

However, if the specified directory does not even exist, or is not a
directory, we should stop right there, with an error message.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-30 23:07:31 -07:00
Johannes Schindelin
de1f68a968 archive --add-virtual-file: allow paths containing colons
By allowing the path to be enclosed in double-quotes, we can avoid
the limitation that paths cannot contain colons.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-30 23:07:31 -07:00
Johannes Schindelin
237a1d138c archive: optionally add "virtual" files
With the `--add-virtual-file=<path>:<content>` option, `git archive` now
supports use cases where relatively trivial files need to be added that
do not exist on disk.

This will allow us to generate `.zip` files with generated content,
without having to add said content to the object database and without
having to write it out to disk.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
[jc: tweaked <path> handling]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-30 23:07:22 -07:00
Junio C Hamano
b02fdbc80a pathspec: correct an empty string used as a pathspec element
Pathspecs with only negative elements did not work with some
commands that pass the pathspec along to a subprocess.  For
instance,

    $ git add -p -- ':!*.txt'

should add everything except for paths ending in ".txt", but it gets
complaint from underlying "diff-index" and aborts.

We used to error out when a pathspec with only negative elements in
it, like the one in the above example.  Later, 859b7f1d (pathspec:
don't error out on all-exclusionary pathspec patterns, 2017-02-07)
updated the logic to add an empty string as an extra element.  The
intention was to let the extra element to match everything and let
the negative ones given by the user to subtract from it.

At around the same time, we were migrating from "an empty string is
a valid pathspec element that matches everything" to "either a dot
or ":/" is used to match all, and an empty string is rejected",
between d426430e (pathspec: warn on empty strings as pathspec,
2016-06-22) and 9e4e8a64 (pathspec: die on empty strings as
pathspec, 2017-06-06).  I think 9e4e8a64, which happened long after
859b7f1d happened, was not careful enough to turn the empty string
859b7f1d added to either a dot or ":/".

A care should be taken as the definition of "everything" depends on
subcommand.  For the purpose of "add -p", adding a "." to add
everything in the current directory is the right thing to do.  But
for some other commands, ":/" (i.e. really really everything, even
things outside the current subdirectory) is the right choice.

We would break commands in a big way if we get this wrong, so add a
handful of test pieces to make sure the resulting code still
excludes the paths that are expected and includes "everything" else.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-29 15:42:18 -07:00
Junio C Hamano
23f2356fd9 Merge branch 'rs/document-archive-prefix' into js/scalar-diagnose
* rs/document-archive-prefix:
  archive: improve documentation of --prefix
2022-05-28 10:38:06 -07:00
René Scharfe
a75910602a archive: improve documentation of --prefix
Document the interaction between --add-file and --prefix by giving an
example.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-28 10:29:40 -07:00
Junio C Hamano
05e280c0a6 http.c: clear the 'finished' member once we are done with it
In http.c, the run_active_slot() function allows the given "slot" to
make progress by calling step_active_slots() in a loop repeatedly,
and the loop is not left until the request held in the slot
completes.

Ages ago, we used to use the slot->in_use member to get out of the
loop, which misbehaved when the request in "slot" completes (at
which time, the result of the request is copied away from the slot,
and the in_use member is cleared, making the slot ready to be
reused), and the "slot" gets reused to service a different request
(at which time, the "slot" becomes in_use again, even though it is
for a different request).  The loop terminating condition mistakenly
thought that the original request has yet to be completed.

Today's code, after baa7b67d (HTTP slot reuse fixes, 2006-03-10)
fixed this issue, uses a separate "slot->finished" member that is
set in run_active_slot() to point to an on-stack variable, and the
code that completes the request in finish_active_slot() clears the
on-stack variable via the pointer to signal that the particular
request held by the slot has completed.  It also clears the in_use
member (as before that fix), so that the slot itself can safely be
reused for an unrelated request.

One thing that is not quite clean in this arrangement is that,
unless the slot gets reused, at which point the finished member is
reset to NULL, the member keeps the value of &finished, which
becomes a dangling pointer into the stack when run_active_slot()
returns.  Clear the finished member before the control leaves the
function, which has a side effect of unconfusing compilers like
recent GCC 12 that is over-eager to warn against such an assignment.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-27 15:58:31 -07:00
Frantisek Hrbata
8c49d704ef transport: free local and remote refs in transport_push()
Fix memory leaks in transport_push(), where remote_refs and local_refs
are never freed.

116 bytes in 1 blocks are definitely lost in loss record 56 of 103
   at 0x484486F: malloc (vg_replace_malloc.c:381)
   by 0x4938D7E: strdup (strdup.c:42)
   by 0x628418: xstrdup (wrapper.c:39)
   by 0x4FD454: process_capabilities (connect.c:232)
   by 0x4FD454: get_remote_heads (connect.c:354)
   by 0x610A38: handshake (transport.c:333)
   by 0x612B02: transport_push (transport.c:1302)
   by 0x4803D6: push_with_options (push.c:357)
   by 0x4811D6: do_push (push.c:414)
   by 0x4811D6: cmd_push (push.c:650)
   by 0x405210: run_builtin (git.c:465)
   by 0x405210: handle_builtin (git.c:719)
   by 0x406363: run_argv (git.c:786)
   by 0x406363: cmd_main (git.c:917)
   by 0x404F17: main (common-main.c:56)

5,912 (388 direct, 5,524 indirect) bytes in 2 blocks are definitely lost in loss record 98 of 103
   at 0x4849464: calloc (vg_replace_malloc.c:1328)
   by 0x628705: xcalloc (wrapper.c:150)
   by 0x5C216D: alloc_ref_with_prefix (remote.c:975)
   by 0x5C232A: alloc_ref (remote.c:983)
   by 0x5C232A: one_local_ref (remote.c:2299)
   by 0x5C232A: one_local_ref (remote.c:2289)
   by 0x5BDB03: do_for_each_repo_ref_iterator (iterator.c:418)
   by 0x5B4C4F: do_for_each_ref (refs.c:1486)
   by 0x5B4C4F: refs_for_each_ref (refs.c:1492)
   by 0x5B4C4F: for_each_ref (refs.c:1497)
   by 0x5C6ADF: get_local_heads (remote.c:2310)
   by 0x612A85: transport_push (transport.c:1286)
   by 0x4803D6: push_with_options (push.c:357)
   by 0x4811D6: do_push (push.c:414)
   by 0x4811D6: cmd_push (push.c:650)
   by 0x405210: run_builtin (git.c:465)
   by 0x405210: handle_builtin (git.c:719)
   by 0x406363: run_argv (git.c:786)
   by 0x406363: cmd_main (git.c:917)

Signed-off-by: Frantisek Hrbata <frantisek@hrbata.com>
Reviewed-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-27 14:51:17 -07:00
Frantisek Hrbata
35919bf1ab transport: unify return values and exit point from transport_push()
It seems there is no reason to return 1 instead of -1 when push_refs()
is not set in transport vtable. Let's unify the error return values and
use the done label as a single exit point from transport_push().

Suggested-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Frantisek Hrbata <frantisek@hrbata.com>
Reviewed-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-27 14:51:16 -07:00
Frantisek Hrbata
6448182a83 transport: remove unnecessary indenting in transport_push()
Remove the big indented block for transport_push() check in transport vtable
and let's just return error immediately. Hopefully this makes the code
more readable.

Signed-off-by: Frantisek Hrbata <frantisek@hrbata.com>
Reviewed-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-27 14:51:16 -07:00
Junio C Hamano
43966ab315 revert: optionally refer to commit in the "reference" format
A typical "git revert" commit uses the full title of the original
commit in its title, and starts its body of the message with:

    This reverts commit 8fa7f667cf61386257c00d6e954855cc3215ae91.

This does not encourage the best practice of describing not just
"what" (i.e. "Revert X" on the title says what we did) but "why"
(i.e. and it does not say why X was undesirable).

We can instead phrase this first line of the body to be more like

    This reverts commit 8fa7f667 (do this and that, 2022-04-25)

so that the title does not have to be

    Revert "do this and that"

We can instead use the title to describe "why" we are reverting the
original commit.

Introduce the "--reference" option to "git revert", and also the
revert.reference configuration variable, which defaults to false, to
tweak the title and the first line of the draft commit message for
when creating a "revert" commit.

When this option is in use, the first line of the pre-filled editor
buffer becomes a comment line that tells the user to say _why_.  If
the user exits the editor without touching this line by mistake,
what we prepare to become the first line of the body, i.e. "This
reverts commit 8fa7f667 (do this and that, 2022-04-25)", ends up to
be the title of the resulting commit.  This behaviour is designed to
help such a user to identify such a revert in "git log --oneline"
easily so that it can be further reworded with "git rebase -i" later.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 23:05:03 -07:00
Jeff Hostetler
3294ca6140 t7527: improve implicit shutdown testing in fsmonitor--daemon
Refactor the tests that exercise implicit shutdown cases
to make them more robust and less racy.

The fsmonitor--daemon will implicitly shutdown in a variety
of situations, such as when the ".git" directory is deleted
or renamed.

The existing tests would delete or rename the directory, sleep
for one second, and then check the status of the daemon.  This
is racy, since the client/status command has no way to sync
with the daemon.  This was noticed occasionally on very slow
CI build machines where it would cause a random test to fail.

Replace the simple sleep with a sleep-and-retry loop.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:28 -07:00
Jeff Hostetler
53fcfbc84f fsmonitor--daemon: allow --super-prefix argument
Create a test in t7527 to verify that we get a stray warning from
`git fsmonitor--daemon start` when indirectly called from
`git submodule absorbgitdirs`.

Update `git fsmonitor--daemon` to take (and ignore) the `--super-prefix`
argument to suppress the warning.

When we have:

1. a submodule with a `sub/.git/` directory (rather than a `sub/.git`
file).

2. `core.fsmonitor` is turned on in the submodule, but the daemon is
not yet started in the submodule.

3. and someone does a `git submodule absorbgitdirs` in the super.

Git will recursively invoke `git submodule--helper absorb-git-dirs`
in the submodule.  This will read the index and may attempt to start
the fsmonitor--daemon with the `--super-prefix` argument.

`git fsmonitor--daemon start` does not accept the `--super-prefix`
argument and causes a warning to be issued.

This does not cause a problem because the `refresh_index()` code
assumes a trivial response if the daemon does not start.

The net-net is a harmelss, but stray warning.  Lets eliminate the
warning.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:28 -07:00
Jeff Hostetler
eb299010ee t7527: test Unicode NFC/NFD handling on MacOS
Confirm that the daemon reports events using the on-disk
spelling for Unicode NFC/NFD characters.  On APFS we still
have Unicode aliasing, so we cannot create two files that
only differ by NFC/NFD, but the on-disk format preserves
the spelling used to create the file.  On HFS+ we also
have aliasing, but the path is always stored on disk in
NFD.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:28 -07:00
Jeff Hostetler
00991e1013 t/lib-unicode-nfc-nfd: helper prereqs for testing unicode nfc/nfd
Create a set of prereqs to help understand how file names
are handled by the filesystem when they contain NFC and NFD
Unicode characters.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:27 -07:00
Jeff Hostetler
9915e08f9b t/helper/hexdump: add helper to print hexdump of stdin
Co-authored-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:27 -07:00
Jeff Hostetler
d6d58ff8ab fsmonitor: on macOS also emit NFC spelling for NFD pathname
Emit NFC or NFC and NFD spellings of pathnames on macOS.

MacOS is Unicode composition insensitive, so NFC and NFD spellings are
treated as aliases and collide.  While the spelling of pathnames in
filesystem events depends upon the underlying filesystem, such as
APFS, HFS+ or FAT32, the OS enforces such collisions regardless of
filesystem.

Teach the daemon to always report the NFC spelling and to report
the NFD spelling when stored in that format on the disk.

This is slightly more general than "core.precomposeUnicode".

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:27 -07:00
Jeff Hostetler
caa9c37ec0 t7527: test FSMonitor on case insensitive+preserving file system
Test that FS events from the OS are received using the preserved,
on-disk spelling of files/directories rather than spelling used
to make the change.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:27 -07:00
Jeff Hostetler
f954c7b8ff fsmonitor: never set CE_FSMONITOR_VALID on submodules
Never set CE_FSMONITOR_VALID on the cache-entry of submodule
directories.

During a client command like 'git status', we may need to recurse
into each submodule to compute a status summary for the submodule.
Since the purpose of the ce_flag is to let Git avoid scanning a
cache-entry, setting the flag causes the recursive call to be
avoided and we report incorrect (no status) for the submodule.

We created an OS watch on the root directory of our working
directory and we receive events for everything in the cone
under it.  When submodules are present inside our working
directory, we receive events for both our repo (the super) and
any subs within it.  Since our index doesn't have any information
for items within the submodules, we can't use those events.

We could try to truncate the paths of those events back to the
submodule boundary and mark the GITLINK as dirty, but that
feels expensive since we would have to prefix compare every FS
event that we receive against a list of submodule roots.  And
it still wouldn't be sufficient to correctly report status on
the submodule, since we don't have any space in the cache-entry
to cache the submodule's status (the 'SCMU' bits in porcelain
V2 speak).  That is, the CE_FSMONITOR_VALID bit just says that
we don't need to scan/inspect it because we already know the
answer -- it doesn't say that the item is clean -- and we
don't have space in the cache-entry to store those answers.
So we should always do the recursive scan.

Therefore, we should never set the flag on GITLINK cache-entries.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:27 -07:00
Jeff Hostetler
7667f9d2ae t/perf/p7527: add perf test for builtin FSMonitor
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:27 -07:00
Jeff Hostetler
b5337082b3 t7527: FSMonitor tests for directory moves
Create unit tests to move a directory.  Verify that `git status`
gives the same result with and without FSMonitor enabled.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:27 -07:00
Jeff Hostetler
95a4e78a74 fsmonitor: optimize processing of directory events
Teach Git to perform binary search over the cache-entries for a directory
notification and then linearly scan forward to find the immediate children.

Previously, when the FSMonitor reported a modified directory Git would
perform a linear search on the entire cache-entry array for all
entries matching that directory prefix and invalidate them.  Since the
cache-entry array is already sorted, we can use a binary search to
find the first matching entry and then only linearly walk forward and
invalidate entries until the prefix changes.

Also, the original code would invalidate anything having the same
directory prefix.  Since a directory event should only be received for
items that are immediately within the directory (and not within
sub-directories of it), only invalidate those entries and not the
whole subtree.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:27 -07:00
Jeff Hostetler
de7e0b58ea fsm-listen-darwin: shutdown daemon if worktree root is moved/renamed
Teach the listener thread to shutdown the daemon if the spelling of the
worktree root directory changes.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:27 -07:00
Jeff Hostetler
6504cfd392 fsm-health-win32: force shutdown daemon if worktree root moves
Force shutdown fsmonitor daemon if the worktree root directory
is moved, renamed, or deleted.

Use Windows low-level GetFileInformationByHandle() to get and
compare the Windows system unique ID for the directory with a
cached version when we started up.  This lets us detect the
case where someone renames the directory that we are watching
and then creates a new directory with the original pathname.

This is important because we are listening to a named pipe for
requests and they are stored in the Named Pipe File System (NPFS)
which a kernel-resident pseudo filesystem not associated with
the actual NTFS directory.

For example, if the daemon was watching "~/foo/", it would have
a directory-watch handle on that directory and a named-pipe
handle for "//./pipe/...foo".  Moving the directory to "~/bar/"
does not invalidate the directory handle.  (So the daemon would
actually be watching "~/bar" but listening on "//./pipe/...foo".
If the user then does "git init ~/foo" and causes another daemon
to start, the first daemon will still have ownership of the pipe
and the second daemon instance will fail to start.  "git status"
clients in "~/foo" will ask "//./pipe/...foo" about changes and
the first daemon instance will tell them about "~/bar".

This commit causes the first daemon to shutdown if the system unique
ID for "~/foo" changes (changes from what it was when the daemon
started).  Shutdown occurs after a periodic poll.  After the
first daemon exits and releases the lock on the named pipe,
subsequent Git commands may cause another daemon to be started
on "~/foo".  Similarly, a subsequent Git command may cause another
daemon to be started on "~/bar".

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:27 -07:00
Jeff Hostetler
90a70fa809 fsm-health-win32: add polling framework to monitor daemon health
Extend the Windows version of the "health" thread to periodically
inspect the system and shutdown if warranted.

This commit updates the thread's wait loop to use a timeout and
defines a (currently empty) table of functions to poll the system.

A later commit will add functions to the table to actually
inspect the system.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:27 -07:00
Jeff Hostetler
d06055501b fsmonitor--daemon: stub in health thread
Create another thread to watch over the daemon process and
automatically shut it down if necessary.

This commit creates the basic framework for a "health" thread
to monitor the daemon and/or the file system.  Later commits
will add platform-specific code to do the actual work.

The "health" thread is intended to monitor conditions that
would be difficult to track inside the IPC thread pool and/or
the file system listener threads.  For example, when there are
file system events outside of the watched worktree root or if
we want to have an idle-timeout auto-shutdown feature.

This commit creates the health thread itself, defines the thread-proc
and sets up the thread's event loop.  It integrates this new thread
into the existing IPC and Listener thread models.

This commit defines the API to the platform-specific code where all of
the monitoring will actually happen.

The platform-specific code for MacOS is just stubs.  Meaning that the
health thread will immediately exit on MacOS, but that is OK and
expected.  Future work can define MacOS-specific monitoring.

The platform-specific code for Windows sets up enough of the
WaitForMultipleObjects() machinery to watch for system and/or custom
events.  Currently, the set of wait handles only includes our custom
shutdown event (sent from our other theads).  Later commits in this
series will extend the set of wait handles to monitor other
conditions.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:27 -07:00
Jeff Hostetler
207534e423 fsmonitor--daemon: rename listener thread related variables
Rename platform-specific listener thread related variables
and data types as we prepare to add another backend thread
type.

[] `struct fsmonitor_daemon_backend_data` becomes `struct fsm_listen_data`
[] `state->backend_data` becomes `state->listen_data`
[] `state->error_code` becomes `state->listen_error_code`

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:26 -07:00
Jeff Hostetler
802aa31840 fsmonitor--daemon: prepare for adding health thread
Refactor daemon thread startup to make it easier to start
a third thread class to monitor the health of the daemon.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:26 -07:00
Jeff Hostetler
39664e9309 fsmonitor--daemon: cd out of worktree root
Teach the fsmonitor--daemon to CD outside of the worktree
before starting up.

The common Git startup mechanism causes the CWD of the daemon process
to be in the root of the worktree.  On Windows, this causes the daemon
process to hold a locked handle on the CWD and prevents other
processes from moving or deleting the worktree while the daemon is
running.

CD to HOME before entering main event loops.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:26 -07:00
Jeff Hostetler
8e8f4b814b fsm-listen-darwin: ignore FSEvents caused by xattr changes on macOS
Ignore FSEvents resulting from `xattr` changes.  Git does not care about
xattr's or changes to xattr's, so don't waste time collecting these
events in the daemon nor transmitting them to clients.

Various security tools add xattrs to files and/or directories, such as
to mark them as having been downloaded.  We should ignore these events
since it doesn't affect the content of the file/directory or the normal
meta-data that Git cares about.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:26 -07:00
Jeff Hostetler
9968ed73ff unpack-trees: initialize fsmonitor_has_run_once in o->result
Initialize `o->result.fsmonitor_has_run_once` based upon value
in `o->src_index->fsmonitor_has_run_once` to prevent a second
fsmonitor query during the tree traversal and possibly getting
a skewed view of the working directory.

The checkout code has already talked to the fsmonitor and the
traversal is updating the index as it traverses, so there is
no need to query the fsmonitor.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:26 -07:00
Jeff Hostetler
ddc5dacfb3 fsmonitor-settings: NTFS and FAT32 on MacOS are incompatible
On MacOS mark repos on NTFS or FAT32 volumes as incompatible.

The builtin FSMonitor used Unix domain sockets on MacOS for IPC
with clients.  These sockets are kept in the .git directory.
Unix sockets are not supported by NTFS and FAT32, so the daemon
cannot start up.

Test for this during our compatibility checking so that client
commands do not keep trying to start the daemon.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:26 -07:00
Jeff Hostetler
d989b266c1 fsmonitor-settings: remote repos on Windows are incompatible
Teach Git to detect remote working directories on Windows and mark them as
incompatible with FSMonitor.

With this `git fsmonitor--daemon run` will error out with a message like it
does for bare repos.

Client commands, such as `git status`, will not attempt to start the daemon.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:26 -07:00
Jeff Hostetler
1e7be10de0 fsmonitor-settings: remote repos on macOS are incompatible
Teach Git to detect remote working directories on macOS and mark them as
incompatible with FSMonitor.

With this, `git fsmonitor--daemon run` will error out with a message
like it does for bare repos.

Client commands, like `git status`, will not attempt to start the daemon.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:26 -07:00
Jeff Hostetler
a85ad67bbd fsmonitor-settings: stub in macOS-specific incompatibility checking
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:26 -07:00
Jeff Hostetler
5c58fbd265 fsmonitor-settings: VFS for Git virtual repos are incompatible
VFS for Git virtual repositories are incompatible with FSMonitor.

VFS for Git is a downstream fork of Git.  It contains its own custom
file system watcher that is aware of the virtualization.  If a working
directory is being managed by VFS for Git, we should not try to watch
it because we may get incomplete results.

We do not know anything about how VFS for Git works, but we do
know that VFS for Git working directories contain a well-defined
config setting.  If it is set, mark the working directory as
incompatible.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:26 -07:00
Jeff Hostetler
d33c804dae fsmonitor-settings: stub in Win32-specific incompatibility checking
Extend generic incompatibility checkout with platform-specific
mechanism.  Stub in Win32 version.

In the existing fsmonitor-settings code we have a way to mark
types of repos as incompatible with fsmonitor (whether via the
hook and IPC APIs).  For example, we do this for bare repos,
since there are no files to watch.

Extend this exclusion mechanism for platform-specific reasons.
This commit just creates the framework and adds a stub for Win32.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:26 -07:00
Jeff Hostetler
62a62a2830 fsmonitor-settings: bare repos are incompatible with FSMonitor
Bare repos do not have a worktree, so there is nothing for the
daemon watch.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:26 -07:00
Jeff Hostetler
49b398a970 t/helper/fsmonitor-client: create stress test
Create a stress test to hammer on the fsmonitor daemon.
Create a client-side thread pool of n threads and have
each of them make m requests as fast as they can.

We do not currently inspect the contents of the response.
We're only interested in placing a heavy request load on
the daemon.

This test is useful for interactive testing and various
experimentation.  For example, to place additional load
on the daemon while another test is running.  We currently
do not have a test script that actually uses this helper.
We might add such a test in the future.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:26 -07:00
Jeff Hostetler
27b5d4171d t7527: test FSMonitor on repos with Unicode root paths
Create some test repos with UTF8 characters in the pathname of the
root directory and verify that the builtin FSMonitor can watch them.

This test is mainly for Windows where we need to avoid `*A()`
routines.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:25 -07:00
Jeff Hostetler
40f865dc02 fsm-listen-win32: handle shortnames
Teach FSMonitor daemon on Windows to recognize shortname paths as
aliases of normal longname paths.  FSMonitor clients, such as `git
status`, should receive the longname spelling of changed files (when
possible).

Sometimes we receive FS events using the shortname, such as when a CMD
shell runs "RENAME GIT~1 FOO" or "RMDIR GIT~1".  The FS notification
arrives using whatever combination of long and shortnames were used by
the other process.  (Shortnames do seem to be case normalized,
however.)

Use Windows GetLongPathNameW() to try to map the pathname spelling in
the notification event into the normalized longname spelling.  (This
can fail if the file/directory is deleted, moved, or renamed, because
we are asking the FS for the mapping in response to the event and
after it has already happened, but we try.)

Special case the shortname spelling of ".git" to avoid under-reporting
these events.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:25 -07:00
Taylor Blau
a613164257 sha1-file.c: don't freshen cruft packs
We don't bother to freshen objects stored in a cruft pack individually
by updating the `.mtimes` file. This is because we can't portably `mmap`
and write into the middle of a file (i.e., to update the mtime of just
one object). Instead, we would have to rewrite the entire `.mtimes` file
which may incur some wasted effort especially if there a lot of cruft
objects and they are freshened infrequently.

Instead, force the freshening code to avoid an optimizing write by
writing out the object loose and letting it pick up a current mtime.

This works because we prefer the mtime of the loose copy of an object
when both a loose and packed one exist (whether or not the packed copy
comes from a cruft pack or not).

This could certainly do with a test and/or be included earlier in this
series/PR, but I want to wait until after I have a chance to clean up
the overly-repetitive nature of the cruft pack tests in general.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:48:26 -07:00
Taylor Blau
5b92477f89 builtin/gc.c: conditionally avoid pruning objects via loose
Expose the new `git repack --cruft` mode from `git gc` via a new opt-in
flag. When invoked like `git gc --cruft`, `git gc` will avoid exploding
unreachable objects as loose ones, and instead create a cruft pack and
`.mtimes` file.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:48:26 -07:00
Taylor Blau
ddee3703b3 builtin/repack.c: add cruft packs to MIDX during geometric repack
When using cruft packs, the following race can occur when a geometric
repack that writes a MIDX bitmap takes place afterwords:

  - First, create an unreachable object and do an all-into-one cruft
    repack which stores that object in the repository's cruft pack.
  - Then make that object reachable.
  - Finally, do a geometric repack and write a MIDX bitmap.

Assuming that we are sufficiently unlucky as to select a commit from the
MIDX which reaches that object for bitmapping, then the `git
multi-pack-index` process will complain that that object is missing.

The reason is because we don't include cruft packs in the MIDX when
doing a geometric repack. Since the "make that object reachable" doesn't
necessarily mean that we'll create a new copy of that object in one of
the packs that will get rolled up as part of a geometric repack, it's
possible that the MIDX won't see any copies of that now-reachable
object.

Of course, it's desirable to avoid including cruft packs in the MIDX
because it causes the MIDX to store a bunch of objects which are likely
to get thrown away. But excluding that pack does open us up to the above
race.

This patch demonstrates the bug, and resolves it by including cruft
packs in the MIDX even when doing a geometric repack.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:48:26 -07:00