submodule update: add regression test with old style setups

As f178c13fda (Revert "Merge branch 'sb/submodule-core-worktree'",
2018-09-07) was produced shortly before a release, nobody asked for
a regression test to be included. Add a regression test that makes sure
that the invocation of `git submodule update` on old setups doesn't
produce errors as pointed out in f178c13fda.

The place to add such a regression test may look odd in t7412, but
that is the best place as there we setup old style submodule setups
explicitly.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t7412-submodule-absorbgitdirs.sh b/t/t7412-submodule-absorbgitdirs.sh
index ce74c12da2daccd26edbb92070e5ff4eb1f09f9c..1cfa150768d7f813ba9943b4bd17887469cb1c04 100755 (executable)
--- a/t/t7412-submodule-absorbgitdirs.sh
+++ b/t/t7412-submodule-absorbgitdirs.sh
@@ -75,7 +75,12 @@ test_expect_success 're-setup nested submodule' '
        GIT_WORK_TREE=../../../nested git -C sub1/.git/modules/nested config \
                core.worktree "../../../nested" &&
        # make sure this re-setup is correct
-       git status --ignore-submodules=none
+       git status --ignore-submodules=none &&
+
+       # also make sure this old setup does not regress
+       git submodule update --init --recursive >out 2>err &&
+       test_must_be_empty out &&
+       test_must_be_empty err
 '
 
 test_expect_success 'absorb the git dir in a nested submodule' '