tree_entry_interesting(): optimize wildcard matching when base is matched

If base is already matched, skip that part when calling
fnmatch(). This happens quite often if users start a command from
worktree's subdirectory and prefix is usually prepended to all
pathspecs.

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

t/t4010-diff-pathspec.sh

@@ -84,4 +84,22 @@ test_expect_success 'diff-tree -r with wildcard' '
 	test_cmp expected result
 '
 
+test_expect_success 'diff-tree with wildcard shows dir also matches' '
+	git diff-tree --name-only $tree $tree2 -- "path1/f*" >result &&
+	echo path1 >expected &&
+	test_cmp expected result
+'
+
+test_expect_success 'diff-tree -r with wildcard from beginning' '
+	git diff-tree -r --name-only $tree $tree2 -- "path1/*file1" >result &&
+	echo path1/file1 >expected &&
+	test_cmp expected result
+'
+
+test_expect_success 'diff-tree -r with wildcard' '
+	git diff-tree -r --name-only $tree $tree2 -- "path1/f*" >result &&
+	echo path1/file1 >expected &&
+	test_cmp expected result
+'
+
 test_done

tree-walk.c

@@ -595,6 +595,20 @@ int tree_entry_interesting(const struct name_entry *entry,
 					match + baselen, matchlen - baselen,
 					&never_interesting))
 				return 1;
+
+			if (ps->items[i].has_wildcard) {
+				if (!fnmatch(match + baselen, entry->path, 0))
+					return 1;
+
+				/*
+				 * Match all directories. We'll try to
+				 * match files later on.
+				 */
+				if (ps->recursive && S_ISDIR(entry->mode))
+					return 1;
+			}
+
+			continue;
 		}
 
 match_wildcards: