tree-walk.c: ignore trailing slash on submodule in tree_entry_interesting()

We do ignore trailing slash on a directory, so pathspec "abc/" matches
directory "abc". A submodule is also a directory. Apply the same logic
to it. This makes "git log submodule-path" and "git log submodule-path/"
produce the same output.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: pclouds

t/t4010-diff-pathspec.sh

@@ -110,4 +110,21 @@ test_expect_success 'diff-tree -r with wildcard' '
 	test_cmp expected result
 '
 
+test_expect_success 'setup submodules' '
+	test_tick &&
+	git init submod &&
+	( cd submod && test_commit first; ) &&
+	git add submod &&
+	git commit -m first &&
+	( cd submod && test_commit second; ) &&
+	git add submod &&
+	git commit -m second
+'
+
+test_expect_success 'diff-tree ignores trailing slash on submodule path' '
+	git diff --name-only HEAD^ HEAD submod >expect &&
+	git diff --name-only HEAD^ HEAD submod/ >actual &&
+	test_cmp expect actual
+'
+
 test_done

tree-walk.c

@@ -543,7 +543,7 @@ static int match_entry(const struct pathspec_item *item,
 	if (matchlen > pathlen) {
 		if (match[pathlen] != '/')
 			return 0;
-		if (!S_ISDIR(entry->mode))
+		if (!S_ISDIR(entry->mode) && !S_ISGITLINK(entry->mode))
 			return 0;
 	}