1 file changed, 27 insertions, 0 deletions
diff --git a/tests/t0003-cache.sh b/tests/t0003-cache.sh
index 7e92b05..945ac63 100755
--- a/tests/t0003-cache.sh
+++ b/tests/t0003-cache.sh
@@ -267,4 +267,31 @@ test_expect_success 'a slot stays locked while an exec filter runs' '
 	! grep "Unable to publish" first.err
 '
 
+# An flock lasts until the last copy of its descriptor closes, so a filter
+# may hold the slot's lock file only as the stdout it writes the page to. A
+# stray copy would keep the slot locked for as long as the filter, or
+# anything it leaves running, lives on.
+test_expect_success PERL 'a filter holds the lock file only as its stdout' '
+	rm -rf cache3 && mkdir cache3 &&
+	write_script fd-filter "$PERL_PATH" <<-\EOF &&
+	use POSIX qw(fstat);
+	1 while <STDIN>;
+	my @lock = stat $ENV{LOCK_FILE} or die "$!\n";
+	my @fds = grep {
+		my @fd = fstat($_);
+		@fd && $fd[0] == $lock[0] && $fd[1] == $lock[1]
+	} 0 .. 255;
+	print "lock file on fd @fds.\n";
+	EOF
+	{
+		echo "cache-size=1" &&
+		sed "/^cache-size=/d" bigkeyrc &&
+		echo "repo.readme=:file-1" &&
+		echo "repo.about-filter=exec:$PWD/fd-filter"
+	} >fdrc &&
+	LOCK_FILE="$PWD/cache3/00000000.lock" CGIT_CONFIG="$PWD/fdrc" \
+	QUERY_STRING="url=bigpage/about/" cgit >fd.out &&
+	grep -F "lock file on fd 1." fd.out
+'
+
 test_done