[php-src] Issue #8255: using enum in $_SESSION variable causes session_start to error "Failed to decode session object. "

Issue: https://github.com/php/php-src/issues/8255 Comment Author: iluuu1994 Enums are a little different than objects in that they don't support session_start() when the enum has not yet been defined. For other objects, PHP would create a __PHP_Incomplete_Class instance. To fix this error, make sure the enum is either loaded or autoloadable when you call session_start(). I don't think this is properly documented so I'm converting this to a documentation issue.