1--TEST-- 2Inherited DateTimePeriod serialisation with custom properties 3--FILE-- 4<?php 5date_default_timezone_set("Europe/London"); 6 7class MyDatePeriod extends DatePeriod 8{ 9 public function __construct( 10 DateTimeInterface $start, 11 DateInterval $interval, 12 int $recurrences, 13 int $options = 0, 14 public ?bool $myProperty = null, 15 ) { 16 parent::__construct($start, $interval, $recurrences, $options); 17 } 18} 19 20$d = new MyDatePeriod(new DateTimeImmutable(), new DateInterval("PT5S"), 5, myProperty: true); 21$e = unserialize(serialize($d)); 22var_dump($e->myProperty); 23?> 24--EXPECTF-- 25bool(true) 26