submodule: Add --force option for git submodule update

diff --git a/t/t7406-submodule-update.sh b/t/t7406-submodule-update.sh
index fa9d23aa31302f53cc1c39473492cf545ca5ae87..5d24d9ff74595174a4549bb165fcc8a0800d8120 100755 (executable)
--- a/t/t7406-submodule-update.sh
+++ b/t/t7406-submodule-update.sh
@@ -74,6 +74,29 @@ test_expect_success 'submodule update detaching the HEAD ' '
        )
 '
 
+test_expect_success 'submodule update should fail due to local changes' '
+       (cd super/submodule &&
+        git reset --hard HEAD~1 &&
+        echo "local change" > file
+       ) &&
+       (cd super &&
+        (cd submodule &&
+         compare_head
+        ) &&
+        test_must_fail git submodule update submodule
+       )
+'
+test_expect_success 'submodule update should throw away changes with --force ' '
+       (cd super &&
+        (cd submodule &&
+         compare_head
+        ) &&
+        git submodule update --force submodule &&
+        cd submodule &&
+        ! compare_head
+       )
+'
+
 test_expect_success 'submodule update --rebase staying on master' '
        (cd super/submodule &&
          git checkout master