start_command: detect execvp failures early

diff --git a/t/t4021-format-patch-numbered.sh b/t/t4021-format-patch-numbered.sh
index 3c27f0dc19648e6c21ff4b1702f3e93f4b64755e..709b3231ca8d9da631727b4aadfb2f46049d37e9 100755 (executable)
--- a/t/t4021-format-patch-numbered.sh
+++ b/t/t4021-format-patch-numbered.sh
@@ -86,6 +86,13 @@ test_expect_success 'format.numbered && --no-numbered' '
 
 '
 
+test_expect_success 'format.numbered && --keep-subject' '
+
+       git format-patch --keep-subject --stdout HEAD^ >patch4a &&
+       grep "^Subject: Third" patch4a
+
+'
+
 test_expect_success 'format.numbered = auto' '
 
        git config format.numbered auto