Fatal Error occurs when calling msgpack_unpack() function in PHP 7.4 or higher environment.

[suzunone]

Hello,
Fatal Error occurs when calling msgpack_unpack() function in PHP 7.4 or higher environment.

The msgpack_unpack() function can be used if pecl msgpack is enabled.
https://pecl.php.net/package/msgpack

I encountered an issue with the following code:

$now = \Carbon\Carbon::parse('2018-06-01');
$message = @msgpack_pack($now);
$copy = msgpack_unpack($message);

Carbon version: 2.46.0

PHP version: 7.4.14

pecl msgpack version:msgpack-2.1.2
https://pecl.php.net/package/msgpack

I expected to get:

PHP Fatal error:  Uncaught Error: Invalid serialization data for DateTime object in ./vendor/nesbot/carbon/src/Carbon/Traits/Serialization.php:131
Stack trace:
#0 ./vendor/nesbot/carbon/src/Carbon/Traits/Serialization.php(131): DateTime->__wakeup()
#1 [internal function]: Carbon\Carbon->__wakeup()
#2 ./test.php(6): msgpack_unpack('\x84\xC0\xADCarbon\\Carbo...')
#3 {main}
  thrown in ./vendor/nesbot/carbon/src/Carbon/Traits/Serialization.php on line 131

But I actually get:

$now  = $copy;

Thanks!

[kylekatarnls]

Hello, 👋

Does the following work:

$now = new DateTime('2018-06-01');
$message = @msgpack_pack($now);
$copy = msgpack_unpack($message);

If it does not, then it would be way more relevant to fix the error in msgpack as it impact any DateTime sub-class.

Else it means it impact only classes that extends DateTime and override parent::__wakeup() which is still a normal PHP case that should work in PHP >= 7.4 as per the unserialize() test:

Carbon/tests/Carbon/SerializationTest.php

Line 54 in b5cb758

$this->assertEquals(Carbon::now(), unserialize(serialize(Carbon::now())));

Replacing __wakeup with __construct as proposed #2300 would be a work-around that may cause other issues. DateTime::__wakeup is supposed to be called on unserialization and I'm a bit reluctant to short-circuit it just to please a minor package.

Finding what exactly msgpack is failing on here may help to get a better long-term fix.

[suzunone]

Hello,
Thanks for your reply.

If it use the vanilla DateTime class instead of Carbon as suggested, it works fine.

<?php

$now = new DateTime('2018-06-01');
$message = @msgpack_pack($now);
$copy = msgpack_unpack($message);

var_dump($copy);

test.php:7
class DateTime#2 (3) {
  public $date =>
  string(26) "2018-06-01 00:00:00.000000"
  public $timezone_type =>
  int(3)
  public $timezone =>
  string(10) "America/Toronto"
}

If it call __wakeup() method directly, as in the following example, will get a Fatal error.

<?php

$now = new DateTime('2018-06-01');
$now->__wakeup();

PHP Fatal error:  Uncaught Error: Invalid serialization data for DateTime object in ./test.php:4
Stack trace:
#0 /data/webapp/test.php(4): DateTime->__wakeup()
#1 {main}
  thrown in /data/webapp/test.php on line 4

This error did not occur in 7.3 or earlier.

Pecl msgpack calls __wakeup() method when msgpack_unpack() is called, as expected.
I haven't tried other libraries than msgpack, but I think the same problem may occur with similar serialize libraries.