Return type fixed to be consistent and prevent type confusion

Author: Webklex

src/Connection/Protocols/LegacyProtocol.php

@@ -559,7 +559,11 @@ public function done() {
  * @return array message ids
  */
  public function search(array $params, $uid = IMAP::ST_UID) {
- return \imap_search($this->stream, $params[0], $uid ? IMAP::ST_UID : IMAP::NIL);
+ $result = \imap_search($this->stream, $params[0], $uid ? IMAP::ST_UID : IMAP::NIL);
+ if ($result === false) {
+ return [];
+ }
+ return $result;
  }
 
  /**