summaryrefslogtreecommitdiff
path: root/templates/hooks--fsmonitor-watchman.sample
AgeCommit message (Collapse)AuthorFilesLines
2020-01-23fsmonitor: add fsmonitor hook scripts for version 2Libravatar Kevin Willford1-52/+116
Version 2 of the fsmonitor hooks is passed the version and an update token and must pass back a last update token to use for subsequent calls to the hook. Signed-off-by: Kevin Willford <Kevin.Willford@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-06fsmonitor: fix watchman integrationLibravatar Kevin Willford1-9/+4
When running Git commands quickly -- such as in a shell script or the test suite -- the Git commands frequently complete and start again during the same second. The example fsmonitor hooks to integrate with Watchman truncate the nanosecond times to seconds. In principle, this is fine, as Watchman claims to use inclusive comparisons [1]. The result should only be an over-representation of the changed paths since the last Git command. However, Watchman's own documentation claims "Using a timestamp is prone to race conditions in understanding the complete state of the file tree" [2]. All of their documented examples use a "clockspec" that looks like 'c:123:234'. Git should eventually learn how to store this type of string to provide a stronger integration, but that will be a more invasive change. When using GIT_TEST_FSMONITOR="$(pwd)/t7519/fsmonitor-watchman", scripts such as t7519-wtstatus.sh fail due to these race conditions. In fact, running any test script with GIT_TEST_FSMONITOR pointing at t/t7519/fsmonitor-wathcman will cause failures in the test_commit function. The 'git add "$indir$file"' command fails due to not enough time between the creation of '$file' and the 'git add' command. For now, subtract one second from the timestamp we pass to Watchman. This will make our window large enough to avoid these race conditions. Increasing the window causes tests like t7519-wtstatus.sh to pass. When the integration was introduced in def437671 (fsmonitor: add a sample integration script for Watchman, 2018-09-22), the query included an expression that would ignore files created and deleted in that window. The performance reason for this change was to ignore temporary files created by a build between Git commands. However, this causes failures in script scenarios where Git is creating or deleting files quickly. When using GIT_TEST_FSMONITOR as before, t2203-add-intent.sh fails due to this add-and-delete race condition. By removing the "expression" from the Watchman query, we remove this race condition. It will lead to some performance degradation in the case of users creating and deleting temporary files inside their working directory between Git commands. However, that is a cost we need to pay to be correct. [1] https://github.com/facebook/watchman/blob/master/query/since.cpp#L35-L39 [2] https://facebook.github.io/watchman/docs/clockspec.html Helped-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Kevin Willford <Kevin.Willford@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-13fsmonitor: simplify determining the git worktree under WindowsLibravatar Ben Peart1-10/+3
Simplify and speed up the process of finding the git worktree when running on Windows by keeping it in perl and avoiding spawning helper processes. Signed-off-by: Ben Peart <benpeart@microsoft.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-10fsmonitor: read from getcwd(), not the PWD environment variableLibravatar Alex Vandiver1-1/+2
Though the process has chdir'd to the root of the working tree, the PWD environment variable is only guaranteed to be updated accordingly if a shell is involved -- which is not guaranteed to be the case. That is, if `/usr/bin/perl` is a binary, $ENV{PWD} is unchanged from whatever spawned `git` -- if `/usr/bin/perl` is a trivial shell wrapper to the real `perl`, `$ENV{PWD}` will have been updated to the root of the working copy. Update to read from the Cwd module using the `getcwd` syscall, not the PWD environment variable. The Cygwin case is left unchanged, as it necessarily _does_ go through a shell. Signed-off-by: Alex Vandiver <alexmv@dropbox.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-30fsmonitor: don't bother pretty-printing JSON from watchmanLibravatar Alex Vandiver1-1/+1
This provides modest performance savings. Benchmarking with the following program, with and without `--no-pretty`, we find savings of 23% (0.316s -> 0.242s) in the git repository, and savings of 8% (5.24s -> 4.86s) on a large repository with 580k files in the working copy. #!/usr/bin/perl use strict; use warnings; use IPC::Open2; use JSON::XS; my $pid = open2(\*CHLD_OUT, \*CHLD_IN, "watchman -j @ARGV") or die "open2() failed: $!\n" . "Falling back to scanning...\n"; my $query = qq|["query", "$ENV{PWD}", {}]|; print CHLD_IN $query; close CHLD_IN; my $response = do {local $/; <CHLD_OUT>}; JSON::XS->new->utf8->decode($response); Signed-off-by: Alex Vandiver <alexmv@dropbox.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-04fsmonitor: read entirety of watchman outputLibravatar Alex Vandiver1-4/+2
In Perl, setting $/ sets the string that is used as the "record separator," which sets the boundary that the `<>` construct reads to. Setting `local $/ = 0666;` evaluates the octal, getting 438, and stringifies it. Thus, the later read from `<CHLD_OUT>` stops as soon as it encounters the string "438" in the watchman output, yielding invalid JSON; repositories containing filenames with SHA1 hashes are able to trip this easily. Set `$/` to undefined, thus slurping all output from watchman. Also close STDIN which is provided to watchman, to better guarantee that we cannot deadlock with watchman while both attempting to read. Signed-off-by: Alex Vandiver <alexmv@dropbox.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-04fsmonitor: MINGW support for watchman integrationLibravatar Ben Peart1-1/+1
Instead of just taking $ENV{'PWD'}, use the same logic that converts PWD to $git_work_tree on MSYS_NT in the watchman integration hook script also on MINGW. Signed-off-by: Ben Peart <benpeart@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-01fsmonitor: add a sample integration script for WatchmanLibravatar Ben Peart1-0/+122
This script integrates the new fsmonitor capabilities of git with the cross platform Watchman file watching service. To use the script: Download and install Watchman from https://facebook.github.io/watchman/. Rename the sample integration hook from fsmonitor-watchman.sample to fsmonitor-watchman. Configure git to use the extension: git config core.fsmonitor .git/hooks/fsmonitor-watchman Optionally turn on the untracked cache for optimal performance. Signed-off-by: Ben Peart <benpeart@microsoft.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Christian Couder <christian.couder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>