[PATCH] failure with diff --submodule=diff with moved nested submodule HEAD

[Stefan Beller]

This fails reliable for me.

Signed-off-by: Stefan Beller <sbel...@google.com>
---
 t/t4060-diff-submodule-option-diff-format.sh | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/t/t4060-diff-submodule-option-diff-format.sh 
b/t/t4060-diff-submodule-option-diff-format.sh
index 7e23b55ea4..89bced3484 100755
--- a/t/t4060-diff-submodule-option-diff-format.sh
+++ b/t/t4060-diff-submodule-option-diff-format.sh
@@ -746,4 +746,20 @@ test_expect_success 'diff --submodule=diff with .git file' 
'
        test_cmp expected actual
 '
 
+test_expect_success 'setup nested submodule' '
+       git submodule add -f ./sm2 &&
+       git commit -a -m "add sm2" &&
+       git -C sm2 submodule add ../sm2 &&
+       git -C sm2 commit -a -m "nested sub"
+'
+
+test_expect_success 'move nested submodule HEAD' '
+       git -C sm2/sm2 commit --allow-empty -m "new HEAD"
+'
+
+test_expect_success 'diff --submodule=diff with moved nested submodule HEAD' '
+       git -C sm2 diff --submodule=diff >actual 2>err &&
+       test_must_be_empty err
+'
+
 test_done
-- 
2.12.2.511.g2abb8caf66