grep: use '/' delimiter for paths

If the tree contains a sub-directory then git-grep(1) output contains a
colon character instead of a path separator:

  $ git grep malloc v2.9.3:t
  v2.9.3:t:test-lib.sh:	setup_malloc_check () {
  $ git show v2.9.3:t:test-lib.sh
  fatal: Path 't:test-lib.sh' does not exist in 'v2.9.3'

This patch attempts to use the correct delimiter:

  $ git grep malloc v2.9.3:t
  v2.9.3:t/test-lib.sh:	setup_malloc_check () {
  $ git show v2.9.3:t/test-lib.sh
  (success)

Signed-off-by: Stefan Hajnoczi <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: stefanhaRH

builtin/grep.c

@@ -814,7 +814,9 @@ static int grep_object(struct grep_opt *opt, const struct pathspec *pathspec,
 
 			/* Add a delimiter if there isn't one already */
 			if (name[len - 1] != '/' && name[len - 1] != ':') {
-				strbuf_addch(&base, ':');
+				/* rev: or rev:path/ */
+				char delim = obj->type == OBJ_COMMIT ? ':' : '/';
+				strbuf_addch(&base, delim);
 			}
 		}
 		init_tree_desc(&tree, data, size);

t/t7810-grep.sh

@@ -1445,6 +1445,11 @@ test_expect_success 'grep outputs valid <rev>:<path> for HEAD:t/' '
 	test_cmp expected actual
 '
 
+test_expect_success 'grep outputs valid <rev>:<path> for HEAD:t' '
+	git grep vvv HEAD:t >actual &&
+	test_cmp expected actual
+'
+
 cat >expected <<EOF
 HEAD:t/a/v:vvv
 HEAD:t/v:vvv