If no requests are passed to Requests_CommentModel::findByRequest(), return an empty result early.

application/modules/requests/models/CommentsModel.php

@@ -46,6 +46,12 @@ class Requests_CommentsModel extends Unl_Model
         $db = Zend_Registry::get('db');
         $requestId = $request->getId();
 
+        if (Unl_Util::isArray($requestId) && count($requestId) == 0) {
+            return new Unl_Model_Collection(__CLASS__);
+        } else if (!Unl_Util::isArray($requestId) && !$requestId) {
+            return null;
+        }
+
         $select = new Zend_Db_Select($db);
         $select->from(array('c' => 'creqRequestComments'), array('requestCommentId', 'request'));
         if (Unl_Util::isArray($requestId)) {