EOF
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 nested &&
+ git -C sm2 commit -a -m "nested sub"
+'
+
+test_expect_success 'move nested submodule HEAD' '
+ echo "nested content" >sm2/nested/file &&
+ git -C sm2/nested add file &&
+ git -C sm2/nested commit --allow-empty -m "new HEAD"
+'
+
+test_expect_success 'diff --submodule=diff with moved nested submodule HEAD' '
+ cat >expected <<-EOF &&
+ Submodule nested a5a65c9..b55928c:
+ diff --git a/nested/file b/nested/file
+ new file mode 100644
+ index 0000000..ca281f5
+ --- /dev/null
+ +++ b/nested/file
+ @@ -0,0 +1 @@
+ +nested content
+ EOF
+ git -C sm2 diff --submodule=diff >actual 2>err &&
+ test_must_be_empty err &&
+ test_cmp expected actual
+'
+ test_expect_success 'diff --submodule=diff recurses into nested submodules' '
+ cat >expected <<-EOF &&
+ Submodule sm2 contains modified content
+ Submodule sm2 a5a65c9..280969a:
+ diff --git a/sm2/.gitmodules b/sm2/.gitmodules
+ new file mode 100644
+ index 0000000..3a816b8
+ --- /dev/null
+ +++ b/sm2/.gitmodules
+ @@ -0,0 +1,3 @@
+ +[submodule "nested"]
+ + path = nested
+ + url = ../sm2
+ Submodule nested 0000000...b55928c (new submodule)
+ diff --git a/sm2/nested/file b/sm2/nested/file
+ new file mode 100644
+ index 0000000..ca281f5
+ --- /dev/null
+ +++ b/sm2/nested/file
+ @@ -0,0 +1 @@
+ +nested content
+ diff --git a/sm2/nested/foo8 b/sm2/nested/foo8
+ new file mode 100644
+ index 0000000..db9916b
+ --- /dev/null
+ +++ b/sm2/nested/foo8
+ @@ -0,0 +1 @@
+ +foo8
+ diff --git a/sm2/nested/foo9 b/sm2/nested/foo9
+ new file mode 100644
+ index 0000000..9c3b4f6
+ --- /dev/null
+ +++ b/sm2/nested/foo9
+ @@ -0,0 +1 @@
+ +foo9
+ EOF
+ git diff --submodule=diff >actual 2>err &&
+ test_must_be_empty err &&
+ test_cmp expected actual
+ '
+
test_done