Merge branch 'py/diff-submodule'

* py/diff-submodule:
  is_racy_timestamp(): do not check timestamp for gitlinks
  diff-lib.c: rename check_work_tree_entity()
  diff: a submodule not checked out is not modified
  Add t7506 to test submodule related functions for git-status
  t4027: test diff for submodule with empty directory

t/t4027-diff-submodule.sh

@@ -50,4 +50,11 @@ test_expect_success 'git diff-files --raw' '
 	test_cmp expect actual.files
 '
 
+test_expect_success 'git diff (empty submodule dir)' '
+	: >empty &&
+	rm -rf sub/* sub/.git &&
+	git diff > actual.empty &&
+	test_cmp empty actual.empty
+'
+
 test_done

t/t7506-status-submodule.sh

@@ -0,0 +1,38 @@
+#!/bin/sh
+
+test_description='git-status for submodule'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_create_repo sub
+	cd sub &&
+	: >bar &&
+	git add bar &&
+	git commit -m " Add bar" &&
+	cd .. &&
+	git add sub &&
+	git commit -m "Add submodule sub"
+'
+
+test_expect_success 'status clean' '
+	git status |
+	grep "nothing to commit"
+'
+test_expect_success 'status -a clean' '
+	git status -a |
+	grep "nothing to commit"
+'
+test_expect_success 'rm submodule contents' '
+	rm -rf sub/* sub/.git
+'
+test_expect_success 'status clean (empty submodule dir)' '
+	git status |
+	grep "nothing to commit"
+'
+test_expect_success 'status -a clean (empty submodule dir)' '
+	git status -a |
+	grep "nothing to commit"
+'
+
+test_done