[GSoC PATCH v2] apply: report the location of corrupt patches

From

JWJialong Wang <jerrywang183@yahoo.com>

Date

Mar 16, 2026, 11:34 UTC

Message-ID

<20260316113459.77794-1-jerrywang183@yahoo.com>

In-Reply-To

<20260315231538.68586-1-jerrywang183@yahoo.com>

Add tests for file input, standard input, and multiple patch inputs.

Signed-off-by: Jialong Wang <jerrywang183@yahoo.com>
---
Changes since v1:
- reset the line number for each patch input
- add a test for multiple patch inputs where one input is corrupted

 apply.c               |  4 +++-
 t/t4100-apply-stat.sh | 38 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/apply.c b/apply.c
index b6dd1066a0..b7b0a201b3 100644
--- a/apply.c
+++ b/apply.c
@@ -1875,7 +1875,8 @@ static int parse_single_patch(struct apply_state *state,
 		len = parse_fragment(state, line, size, patch, fragment);
 		if (len <= 0) {
 			free(fragment);
-			return error(_("corrupt patch at line %d"), state->linenr);
+			return error(_("corrupt patch at %s:%d"),
+				     state->patch_input_file, state->linenr);
 		}
 		fragment->patch = line;
 		fragment->size = len;
@@ -4825,6 +4826,7 @@ static int apply_patch(struct apply_state *state,
 	int flush_attributes = 0;
 
 	state->patch_input_file = filename;
+	state->linenr = 1;
 	if (read_patch_file(&buf, fd) < 0)
 		return -128;
 	offset = 0;
diff --git a/t/t4100-apply-stat.sh b/t/t4100-apply-stat.sh
index a5664f3eb3..b19fc9fe50 100755
--- a/t/t4100-apply-stat.sh
+++ b/t/t4100-apply-stat.sh
@@ -48,7 +48,43 @@ test_expect_success 'applying a hunk header which overflows fails' '
 	+b
 	EOF
 	test_must_fail git apply patch 2>err &&
-	echo "error: corrupt patch at line 4" >expect &&
+	echo "error: corrupt patch at patch:4" >expect &&
+	test_cmp expect err
+'
+
+test_expect_success 'applying a hunk header which overflows from stdin fails' '
+	cat >patch <<-\EOF &&
+	diff -u a/file b/file
+	--- a/file
+	+++ b/file
+	@@ -98765432109876543210 +98765432109876543210 @@
+	-a
+	+b
+	EOF
+	test_must_fail git apply <patch 2>err &&
+	echo "error: corrupt patch at <stdin>:4" >expect &&
+	test_cmp expect err
+'
+
+test_expect_success 'applying multiple patches reports the corrupted input' '
+	cat >good.patch <<-\EOF &&
+	diff -u a/file b/file
+	--- a/file
+	+++ b/file
+	@@ -1 +1 @@
+	-a
+	+b
+	EOF
+	cat >bad.patch <<-\EOF &&
+	diff -u a/file b/file
+	--- a/file
+	+++ b/file
+	@@ -98765432109876543210 +98765432109876543210 @@
+	-a
+	+b
+	EOF
+	test_must_fail git apply --stat --summary good.patch bad.patch 2>err &&
+	echo "error: corrupt patch at bad.patch:4" >expect &&
 	test_cmp expect err
 '
 test_done

-- 
2.51.0