1 file changed, 29 insertions, 0 deletions
diff --git a/tests/t0020-validate-cache.sh b/tests/t0020-validate-cache.sh
index feb6275..ca85d97 100755
--- a/tests/t0020-validate-cache.sh
+++ b/tests/t0020-validate-cache.sh
@@ -154,6 +154,35 @@ test_expect_success 'an ordinary key still fills a slot' '
 	test_line_count = 1 key.slots
 '
 
+# An error page fired after rendering began abandons the fill with part of
+# the page already written into the lock file. That fragment must be
+# discarded along with the file, not replayed to the visitor behind the
+# error page. A commit whose parent object is missing renders its whole
+# info table before the diff machinery fails, which makes it the trigger.
+test_expect_success 'set up a repo missing a parent object' '
+	mkrepo repos/broken 2 &&
+	parent=$(git -C repos/broken rev-parse HEAD^) &&
+	tip=$(git -C repos/broken rev-parse HEAD) &&
+	rm "repos/broken/.git/objects/$(echo "$parent" | cut -c1-2)/$(echo "$parent" | cut -c3-)" &&
+	{
+		echo "virtual-root=/" &&
+		echo "cache-root=$PWD/cache4" &&
+		echo "cache-size=64" &&
+		echo "repo.url=broken" &&
+		echo "repo.path=$PWD/repos/broken/.git"
+	} >brokenrc &&
+	rm -rf cache4 && mkdir cache4
+'
+
+test_expect_success 'an error after output began replays none of it' '
+	CGIT_CONFIG="$PWD/brokenrc" QUERY_STRING="url=broken/commit/&id=$tip" \
+	cgit >broken.out &&
+	grep "Bad commit" broken.out &&
+	test $(grep -c "^Status:" broken.out) = 1 &&
+	ls cache4 >broken.slots &&
+	test_line_count = 0 broken.slots
+'
+
 # An error page reports a condition the repository may grow out of, and a
 # request pinned to an object id would cache it under the never-expiring
 # static ttl. Asking for a commit that does not exist yet must therefore