serializing objects with different class definitions
When it comes to (un)serializing objects in PHP, some things may surprise you. In this post I show what I’ve found out last week, when I was testing serialization with different class definitions. This is generally a bad practice, and shows one of the biggest drawbacks of using serialization for persistent object storage: the serialized data holds a frozen version of an object. As project evolves, and classes change, the serialized information doesn’t change with them. When objects are unserialized with the new class definition, it can result in unexpected behavior. You should take care when using serialization for persistent or temporary storage (ie caching objects in memcache), because every change in the class definition may affect the unserialized objects, causing numerous bugs and crashes.
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