Chovy’s Blog

I came across this error a few times, enough to where I dug around and finally found the real fix to supress the error completely.

Warning: Unknown: Your script possibly relies on a session side-effect which existed until PHP 4.2.3. Please be advised that the session extension does not consider global variables as a source of data, unless register_globals is enabled. You can disable this functionality and this warning by setting session.bug_compat_42 or session.bug_compat_warn to off, respectively in Unknown on line 0

I was able to supress the error by properly unsetting a session variable:

  //replace this:
  $_SESSION[$field] = null;

  //with this:
  unset($_SESSION[$field]);

The warning is triggered by assigning to the $_SESSION super global directly. By using unset(…) we are not assign null directly.