path: root/templates
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authorAlex Vandiver <>2017-10-04 06:27:46 (GMT)
committerJunio C Hamano <>2017-10-04 09:58:53 (GMT)
commit2a387b17c5bc5e0872bed352a41a2b312ea86f9b (patch)
tree28e39bf1dc1bbff4003023509b0222b86b4c6f2c /templates
parentdcdb71f1599734ae46870d3eca11e2093bbd7520 (diff)
fsmonitor: read entirety of watchman output
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 <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'templates')
1 files changed, 2 insertions, 4 deletions
diff --git a/templates/hooks--fsmonitor-watchman.sample b/templates/hooks--fsmonitor-watchman.sample
index c68038ef0..9eba8a7 100755
--- a/templates/hooks--fsmonitor-watchman.sample
+++ b/templates/hooks--fsmonitor-watchman.sample
@@ -49,9 +49,6 @@ launch_watchman();
sub launch_watchman {
- # Set input record separator
- local $/ = 0666;
my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j')
or die "open2() failed: $!\n" .
"Falling back to scanning...\n";
@@ -78,7 +75,8 @@ sub launch_watchman {
print CHLD_IN $query;
- my $response = <CHLD_OUT>;
+ close CHLD_IN;
+ my $response = do {local $/; <CHLD_OUT>};
die "Watchman: command returned no output.\n" .
"Falling back to scanning...\n" if $response eq "";