Differentiate between errors and warnings in session error handler and only assume session was not started if there was an error triggered. It should not throw an exception if there was only a notice or a warning.
Needed for WordPress. Eg there a caching plugin was trying to delete some cache after we executed a DB query, and did cache deletion on the file system triggered a warning. Then Zend_Session assumed the session was not started correctly even though it was and the warning was not related to session_start at all