[php-src] Issue #8152: Cannot hydrate a DateTime instance created without the constructor

Issue: https://github.com/php/php-src/issues/8152 Comment Author: derickr Some historical perspective: - These properties were never meant to be public — as setting these would imply that they would modify the underlying data (they don't). - They were added to be displayed for debugging and tests (through var_dump() and friends). - Somebody later added serialisation support, and __wakeup() etc. - Using __wakeup() to magically make the DateTime properties do something is IMO also a hack. None of the DateTime* classes should have publicly writable properties, and the right way to hydrate these objects is/was by using __set_state. I do find it odd that Foo::__set_state() wouldn't return a Foo class though, and I think I consider that a bug. There is however no other built-in class that implements __set_state() in the standard distribution.