submodule.c: report the submodule that an error occurs in

diff --git a/t/lib-submodule-update.sh b/t/lib-submodule-update.sh
index 1f38a85371ab49790d14d3d4b82a0ee6e52789dd..4ee54325bcdc5813aafcc2a9c823285e2c6fe8ae 100755 (executable)
--- a/t/lib-submodule-update.sh
+++ b/t/lib-submodule-update.sh
@@ -781,7 +781,8 @@ test_submodule_recursing_with_args_common() {
                (
                        cd submodule_update &&
                        git branch -t invalid_sub1 origin/invalid_sub1 &&
-                       test_must_fail $command invalid_sub1 &&
+                       test_must_fail $command invalid_sub1 2>err &&
+                       test_i18ngrep sub1 err &&
                        test_superproject_content origin/add_sub1 &&
                        test_submodule_content sub1 origin/add_sub1
                )