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comparison config/st/.git/hooks/fsmonitor-watchman.sample @ 0:face7f4d84f7

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author Yasuri <yasuri@charliesmp.net>
date Mon, 28 Sep 2026 13:10:19 -0500
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-1:000000000000 0:face7f4d84f7
1 #!/nix/store/w03i01kiakf4wz7jbp1l59c0bhb3pjca-perl-5.42.3/bin/perl
2
3 use strict;
4 use warnings;
5 use IPC::Open2;
6
7 # An example hook script to integrate Watchman
8 # (https://facebook.github.io/watchman/) with git to speed up detecting
9 # new and modified files.
10 #
11 # The hook is passed a version (currently 2) and last update token
12 # formatted as a string and outputs to stdout a new update token and
13 # all files that have been modified since the update token. Paths must
14 # be relative to the root of the working tree and separated by a single NUL.
15 #
16 # To enable this hook, rename this file to "query-watchman" and set
17 # 'git config core.fsmonitor .git/hooks/query-watchman'
18 #
19 my ($version, $last_update_token) = @ARGV;
20
21 # Uncomment for debugging
22 # print STDERR "$0 $version $last_update_token\n";
23
24 # Check the hook interface version
25 if ($version ne 2) {
26 die "Unsupported query-fsmonitor hook version '$version'.\n" .
27 "Falling back to scanning...\n";
28 }
29
30 my $git_work_tree = get_working_dir();
31
32 my $json_pkg;
33 eval {
34 require JSON::XS;
35 $json_pkg = "JSON::XS";
36 1;
37 } or do {
38 require JSON::PP;
39 $json_pkg = "JSON::PP";
40 };
41
42 launch_watchman();
43
44 sub launch_watchman {
45 my $o = watchman_query();
46 if (is_work_tree_watched($o)) {
47 output_result($o->{clock}, @{$o->{files}});
48 }
49 }
50
51 sub output_result {
52 my ($clockid, @files) = @_;
53
54 # Uncomment for debugging watchman output
55 # open (my $fh, ">", ".git/watchman-output.out");
56 # binmode $fh, ":utf8";
57 # print $fh "$clockid\n@files\n";
58 # close $fh;
59
60 binmode STDOUT, ":utf8";
61 print $clockid;
62 print "\0";
63 local $, = "\0";
64 print @files;
65 }
66
67 sub watchman_clock {
68 my $response = qx/watchman clock "$git_work_tree"/;
69 die "Failed to get clock id on '$git_work_tree'.\n" .
70 "Falling back to scanning...\n" if $? != 0;
71
72 return $json_pkg->new->utf8->decode($response);
73 }
74
75 sub watchman_query {
76 my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j --no-pretty')
77 or die "open2() failed: $!\n" .
78 "Falling back to scanning...\n";
79
80 # In the query expression below we're asking for names of files that
81 # changed since $last_update_token but not from the .git folder.
82 #
83 # To accomplish this, we're using the "since" generator to use the
84 # recency index to select candidate nodes and "fields" to limit the
85 # output to file names only. Then we're using the "expression" term to
86 # further constrain the results.
87 my $last_update_line = "";
88 if (substr($last_update_token, 0, 1) eq "c") {
89 $last_update_token = "\"$last_update_token\"";
90 $last_update_line = qq[\n"since": $last_update_token,];
91 }
92 my $query = <<" END";
93 ["query", "$git_work_tree", {$last_update_line
94 "fields": ["name"],
95 "expression": ["not", ["dirname", ".git"]]
96 }]
97 END
98
99 # Uncomment for debugging the watchman query
100 # open (my $fh, ">", ".git/watchman-query.json");
101 # print $fh $query;
102 # close $fh;
103
104 print CHLD_IN $query;
105 close CHLD_IN;
106 my $response = do {local $/; <CHLD_OUT>};
107
108 # Uncomment for debugging the watch response
109 # open ($fh, ">", ".git/watchman-response.json");
110 # print $fh $response;
111 # close $fh;
112
113 die "Watchman: command returned no output.\n" .
114 "Falling back to scanning...\n" if $response eq "";
115 die "Watchman: command returned invalid output: $response\n" .
116 "Falling back to scanning...\n" unless $response =~ /^\{/;
117
118 return $json_pkg->new->utf8->decode($response);
119 }
120
121 sub is_work_tree_watched {
122 my ($output) = @_;
123 my $error = $output->{error};
124 if ($error and $error =~ m/unable to resolve root .* directory (.*) is not watched/) {
125 my $response = qx/watchman watch "$git_work_tree"/;
126 die "Failed to make watchman watch '$git_work_tree'.\n" .
127 "Falling back to scanning...\n" if $? != 0;
128 $output = $json_pkg->new->utf8->decode($response);
129 $error = $output->{error};
130 die "Watchman: $error.\n" .
131 "Falling back to scanning...\n" if $error;
132
133 # Uncomment for debugging watchman output
134 # open (my $fh, ">", ".git/watchman-output.out");
135 # close $fh;
136
137 # Watchman will always return all files on the first query so
138 # return the fast "everything is dirty" flag to git and do the
139 # Watchman query just to get it over with now so we won't pay
140 # the cost in git to look up each individual file.
141 my $o = watchman_clock();
142 $error = $o->{error};
143
144 die "Watchman: $error.\n" .
145 "Falling back to scanning...\n" if $error;
146
147 output_result($o->{clock}, ("/"));
148 return 0;
149 }
150
151 die "Watchman: $error.\n" .
152 "Falling back to scanning...\n" if $error;
153
154 return 1;
155 }
156
157 sub get_working_dir {
158 my $working_dir;
159 if ($^O =~ 'msys' || $^O =~ 'cygwin') {
160 $working_dir = Win32::GetCwd();
161 $working_dir =~ tr/\\/\//;
162 } else {
163 require Cwd;
164 $working_dir = Cwd::cwd();
165 }
166
167 return $working_dir;
168 }