ref-filter: handle nested tags in --points-at option

Tags are dereferenced until reaching a different object type to handle
nested tags, e.g. on checkout. In contrast, "git tag --points-at=..."
fails to list such nested tags because only one level of indirection is
obtained in filter_refs(). Implement the recursive dereferencing for the
"--points-at" option when filtering refs to unify the behaviour.

Signed-off-by: Jan Klötzke <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: jkloetzke

ref-filter.c

@@ -2332,29 +2332,27 @@ static int for_each_fullref_in_pattern(struct ref_filter *filter,
  * of oids. If the given ref is a tag, check if the given tag points
  * at one of the oids in the given oid array.
  * NEEDSWORK:
- * 1. Only a single level of indirection is obtained, we might want to
- * change this to account for multiple levels (e.g. annotated tags
- * pointing to annotated tags pointing to a commit.)
- * 2. As the refs are cached we might know what refname peels to without
+ * As the refs are cached we might know what refname peels to without
  * the need to parse the object via parse_object(). peel_ref() might be a
  * more efficient alternative to obtain the pointee.
  */
 static const struct object_id *match_points_at(struct oid_array *points_at,
 					       const struct object_id *oid,
 					       const char *refname)
 {
-	const struct object_id *tagged_oid = NULL;
 	struct object *obj;
 
 	if (oid_array_lookup(points_at, oid) >= 0)
 		return oid;
 	obj = parse_object(the_repository, oid);
+	while (obj && obj->type == OBJ_TAG) {
+		oid = get_tagged_oid((struct tag *)obj);
+		if (oid_array_lookup(points_at, oid) >= 0)
+			return oid;
+		obj = parse_object(the_repository, oid);
+	}
 	if (!obj)
 		die(_("malformed object at '%s'"), refname);
-	if (obj->type == OBJ_TAG)
-		tagged_oid = get_tagged_oid((struct tag *)obj);
-	if (tagged_oid && oid_array_lookup(points_at, tagged_oid) >= 0)
-		return tagged_oid;
 	return NULL;
 }
 

t/t6302-for-each-ref-filter.sh

@@ -45,6 +45,8 @@ test_expect_success 'check signed tags with --points-at' '
 	sed -e "s/Z$//" >expect <<-\EOF &&
 	refs/heads/side Z
 	refs/tags/annotated-tag four
+	refs/tags/doubly-annotated-tag An annotated tag
+	refs/tags/doubly-signed-tag A signed tag
 	refs/tags/four Z
 	refs/tags/signed-tag four
 	EOF