AclNode now throws exception instead of trigger_error

lib/Cake/Model/AclNode.php

@@ -128,8 +128,7 @@ class AclNode extends Model {
 			$model = ClassRegistry::init(array('class' => $name, 'alias' => $alias));
 
 			if (empty($model)) {
-				trigger_error(__d('cake_dev', "Model class '%s' not found in AclNode::node() when trying to bind %s object", $type, $this->alias), E_USER_WARNING);
-				return null;
+				throw new CakeException('cake_dev', "Model class '%s' not found in AclNode::node() when trying to bind %s object", $type, $this->alias);
 			}
 
 			$tmpRef = null;
@@ -173,7 +172,7 @@ class AclNode extends Model {
 			$result = $db->read($this, $queryData, -1);
 
 			if (!$result) {
-				trigger_error(__d('cake_dev', "AclNode::node() - Couldn't find %s node identified by \"%s\"", $type, print_r($ref, true)), E_USER_WARNING);
+				throw new CakeException(__d('cake_dev', "AclNode::node() - Couldn't find %s node identified by \"%s\"", $type, print_r($ref, true)));
 			}
 		}
 		return $result;