get_ref_dir(): return early if directory cannot be read

diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index dd1acebd88070b75bbbfd07048b5a255aa00e0f3..9fe1d8feab419e1a8065b2ea5881f991edc68855 100755 (executable)
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -653,4 +653,8 @@ test_expect_success 'refuse --edit-description on unborn branch for now' '
        )
 '
 
+test_expect_success '--merged catches invalid object names' '
+       test_must_fail git branch --merged 0000000000000000000000000000000000000000
+'
+
 test_done