dark: fix clone serialization issue in php8.2

[azuradara]

Notes

For some reason serializing a cloned object in PHP 8.2 breaks the serialization recursion, resulting in the creation of two different serializables (different references). The serializer only keeps track of the deepest serializable in the chain, meaning that handled serializable properties can only be accessed by doing the following:

// uninitialized, the serializer does not keep a reference of this serializable
$serializable->property;

// works (if the serializer proper were public)
$serializable->serializer->serializable->property;

Reproduction steps

$cloner = new Cloner([$wrapper]);

$serialized = serialize(clone $cloner);

$deserialized = unserialize($serialized);

$wrapper = $deserialized->data[0];

$srProp = (new \ReflectionObject($wrapper))
    ->getProperty('serializer');

$srProp->setAccessible(true);
$serializer = $srProp->getValue($wrapper);

$sbProp = (new \ReflectionObject($serializer))
    ->getProperty('serializable');

$sbProp->setAccessible(true);
$serializable = $sbProp->getValue($serializer);

dump('DEPTH 1 ID: ' . spl_object_id($wrapper));
dump('DEPTH 1 DESERIALIZED: '.  isset($wrapper->something));

dump('DEPTH 3: ' . spl_object_id($serializable));
dump('DEPTH 3 DESERIALIZED: ' . isset($serializable->something));

// OUTPUT: different serializables, highest depth one isn't serialized
//         the serializer only kept track of the depth 3 one's reference

^ "DEPTH 1 ID: 1522"
^ "DEPTH 1 DESERIALIZED: "
^ "DEPTH 3: 1521"
^ "DEPTH 3 DESERIALIZED: 1"

For reference, here are the serialized values from the Cloner test class introduced in this PR without the __clone() fix:

// without clone
serialize($cloner);

O:20:"Tests\Helpers\Cloner":1:{
  s:4:"data";a:1:{
    i:0;O:21:"Tests\Helpers\Wrapper":1:{
      s:10:"serializer";O:28:"YouCanShop\Cereal\Serializer":3:{
        s:44:"\x00YouCanShop\Cereal\Serializer\x00serializations";a:1:{
          s:9:"something";s:3:"one";
          s:42:"\x00YouCanShop\Cereal\Serializer\x00serializable";r:3; // serializer isn't defined on the serialized serializable
          s:42:"\x00YouCanShop\Cereal\Serializer\x00factoryClass";s:45:"YouCanShop\Cereal\SerializationHandlerFactory";
        }
      }
    }
  }
}

// with clone
serialize(clone $cloner);

O:20:"Tests\Helpers\Cloner":1:{
  s:4:"data";a:1:{
    i:0;O:21:"Tests\Helpers\Wrapper":1:{
      s:10:"serializer";O:28:"YouCanShop\Cereal\Serializer":3:{
        s:44:"\x00YouCanShop\Cereal\Serializer\x00serializations";a:1:{
          s:9:"something";s:3:"one";
        }
        s:42:"\x00YouCanShop\Cereal\Serializer\x00serializable";O:21:"Tests\Helpers\Wrapper":1:{
          s:10:"serializer";O:28:"YouCanShop\Cereal\Serializer":3:{ // serializer is redefined
            s:44:"\x00YouCanShop\Cereal\Serializer\x00serializations";a:1:{
              s:9:"something";s:3:"one";
            }
            s:42:"\x00YouCanShop\Cereal\Serializer\x00serializable";r:7;
            s:42:"\x00YouCanShop\Cereal\Serializer\x00factoryClass";s:45:"YouCanShop\Cereal\SerializationHandlerFactory";
          }
        }
        s:42:"\x00YouCanShop\Cereal\Serializer\x00factoryClass";s:45:"YouCanShop\Cereal\SerializationHandlerFactory";
      }
    }
  }
}