fallback to default MySQL port if not given in mysqli connection

lib/Doctrine/DBAL/Driver/Mysqli/MysqliConnection.php

@@ -50,6 +50,12 @@ class MysqliConnection implements Connection, PingableConnection, ServerInfoAwar
     public function __construct(array $params, $username, $password, array $driverOptions = array())
     {
         $port = isset($params['port']) ? $params['port'] : ini_get('mysqli.default_port');
+
+        // Fallback to default MySQL port if not given.
+        if ( ! $port) {
+            $port = 3306;
+        }
+
         $socket = isset($params['unix_socket']) ? $params['unix_socket'] : ini_get('mysqli.default_socket');
         $dbname = isset($params['dbname']) ? $params['dbname'] : null;