public function getRequiredHandlePHIDs() { $old = $this->getOldValue(); $new = $this->getNewValue(); $type = $this->getTransactionType(); $phids = parent::getRequiredHandlePHIDs(); switch ($type) { case self::TYPE_DEFAULT_QUEUE: if ($old) { $phids[] = $old; } if ($new) { $phids[] = $new; } break; } return $phids; }