Merge branch 'jk/rev-parse-symbolic-parents-fix' into maint

"git rev-parse --symbolic" failed with a more recent notation like
"HEAD^-1" and "HEAD^!".

* jk/rev-parse-symbolic-parents-fix:
  rev-parse: fix parent shorthands with --symbolic

builtin/rev-parse.c

@@ -342,11 +342,16 @@ static int try_parent_shorthands(const char *arg)
 	for (parents = commit->parents, parent_number = 1;
 	     parents;
 	     parents = parents->next, parent_number++) {
+		char *name = NULL;
+
 		if (exclude_parent && parent_number != exclude_parent)
 			continue;
 
+		if (symbolic)
+			name = xstrfmt("%s^%d", arg, parent_number);
 		show_rev(include_parents ? NORMAL : REVERSED,
-			 parents->item->object.oid.hash, arg);
+			 parents->item->object.oid.hash, name);
+		free(name);
 	}
 
 	*dotdot = '^';

t/t6101-rev-parse-parents.sh

@@ -83,12 +83,24 @@ test_expect_success 'final^1^@ = final^1^1 final^1^2' '
 	test_cmp expect actual
 '
 
+test_expect_success 'symbolic final^1^@ = final^1^1 final^1^2' '
+	git rev-parse --symbolic final^1^1 final^1^2 >expect &&
+	git rev-parse --symbolic final^1^@ >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'final^1^! = final^1 ^final^1^1 ^final^1^2' '
 	git rev-parse final^1 ^final^1^1 ^final^1^2 >expect &&
 	git rev-parse final^1^! >actual &&
 	test_cmp expect actual
 '
 
+test_expect_success 'symbolic final^1^! = final^1 ^final^1^1 ^final^1^2' '
+	git rev-parse --symbolic final^1 ^final^1^1 ^final^1^2 >expect &&
+	git rev-parse --symbolic final^1^! >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'large graft octopus' '
 	test_cmp_rev_output b31 "git rev-parse --verify b1^30"
 '
@@ -143,6 +155,12 @@ test_expect_success 'rev-parse merge^-2 = merge^2..merge' '
 	test_cmp expect actual
 '
 
+test_expect_success 'symbolic merge^-1 = merge^1..merge' '
+	git rev-parse --symbolic merge^1..merge >expect &&
+	git rev-parse --symbolic merge^-1 >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'rev-parse merge^-0 (invalid parent)' '
 	test_must_fail git rev-parse merge^-0
 '