Serialization of internal classes

[eymengunay]

Serializer throws ReflectionException when class property is an internal class. (For example DateTime class can not be serialized because of this error)

ReflectionClass::newInstanceWithoutConstructor on php.net

As a temporary solution I've added a if ($ref->isInternal()) check with newInstance method and it seems to work fine.

Do you have any other ideas on how to fix the problem?

[jrbasso]

We can't apply this rule for all internal classes. stdClass, for example, is an internal class but can be instantiated with newInstanceWithoutConstructor. I couldn't find a method to explicit say if the class can initialized or not with that method. A solution probably would be to try/catch the exception and try to use the unserialize alternative. Or maybe just add an special condition to DateTime. I don't think many internal classes would have the same issue.

[eymengunay]

You are definitely right, it is not a complete solution. Looking for similar issues I stumbled upon some results from phpunit mock object library. Here is how they resolved it, hope this helps better:

https://github.com/sebastianbergmann/phpunit-mock-objects/pull/174/files

Anyway, also a simple special condition just for DateTime class sounds completely reasonable.

[jrbasso]

That's interesting, but I did some tests and it doesn't work with DateTime. I guess I will have to put a specific condition to this class for now.

[jrbasso]

You can see it here:

# Unserializing without the properties
$ php -r 'var_dump(unserialize("O:8:\"DateTime\":0:{}"));'
PHP Fatal error:  Invalid serialization data for DateTime object in Command line code on line 1

# Trying to instantiate the class using reflection
$ php -r '(new ReflectionClass("DateTime"))->newInstanceWithoutConstructor();'
PHP Fatal error:  Uncaught exception 'ReflectionException' with message 'Class DateTime is an internal class that cannot be instantiated without invoking its constructor' in Command line code:1
Stack trace:
#0 Command line code(1): ReflectionClass->newInstanceWithoutConstructor()
#1 {main}
  thrown in Command line code on line 1

# The serialized version that can be unserialized
$ php -r 'var_dump(unserialize('"'"'O:8:"DateTime":3:{s:4:"date";s:19:"2014-06-15 03:43:40";s:13:"timezone_type";i:3;s:8:"timezone";s:3:"UTC";}'"'"'));'
object(DateTime)#1 (3) {
  ["date"]=>
  string(19) "2014-06-15 03:43:40"
  ["timezone_type"]=>
  int(3)
  ["timezone"]=>
  string(3) "UTC"
}

[eymengunay]

Thanks for the pr!

PS: I'm not sure if it is better to close the issue (once pr gets merged ofcourse) or keep it open for other possibly similar problems so I'm leaving it to you @jrbasso :)

[jrbasso]

No problem. Thanks for reporting the issue.

The issue will be automatically closed when the PR is merged.