Custom properties of DateTimeImmutable child classes are not serialized

[derrabus]

Description

The following code:

<?php

class MyDateTimeImmutable extends DateTimeImmutable {
    public function __construct(
        string $datetime = "now",
        ?DateTimeZone $timezone = null,
        public ?bool $myProperty = null,
    ) {
        parent::__construct($datetime, $timezone);
    }
}

$datetime = new MyDateTimeImmutable('2022-12-22T11:26:00Z', myProperty: true);
$serialized = serialize($datetime);
$unserialized = unserialize($serialized);

var_dump($unserialized->myProperty);

Resulted in this output:

Fatal error: Uncaught Error: Typed property MyDateTimeImmutable::$myProperty must not be accessed before initialization in /path/to/file.php:17
Stack trace:
#0 {main}
  thrown in /path/to/file.php on line 17

But I expected this output instead:

bool(true)

The propblem can be observed here: https://3v4l.org/8q4Or

Apparently, MyDateTimeImmutable::$myProperty is not included in the serialized string anymore on PHP 8.2.0. On PHP 8.0/8.1, it does appear there and is unserialized properly.

PHP Version

PHP 8.2.0

Operating System

No response

[cmb69]

This is because DateTime(Immutable) (and DateTimeZone) now implement ::__(un)serialize() (#8422). Besides this is not documented, it looks like subclasses have been overlooked. Or is that deliberate, @derickr?

[derickr]

This is not deliberate, and hence a bug.

[OskarStark]

Thank you very much @derickr 🎉 ☀️