I've skimmed through the source code, but cannot find a reason as to why writes do not work after executing session_set_save_handler() with appropriate args when session.save_handler (php.ini) is set to "files".

My scripts are functioning fine if i set session.save_handler to "user".  It only happens when session.save_handler is set to "files" in php.ini, in which case it seems session_set_save_handler() performs a php_alter_ini_entry to change the value of session.save_handler to "user".

I've echoed function names in their appropriate functions to trace how far sessions go after a simple session_start(); $count = 5; session_register("count"); to see if it would write to the database via my functions.  After looking at the output and MySQL logs, I have concluded that it only gets as far as the "read" stage.  It does not seem to attempt to store session variables.

I believe this is a bug, henceforth this submission.