php/php-src — pull request #17 by nikic (2012-03-23 21:00:23+00:00)
Title: Allow resetting error handler (#60738)

This allows the error handler to be reset using `set_error_handler(null)`. As the code suggests this behavior was already previously intended, but the callback check was done too strictly.

See also bug https://bugs.php.net/bug.php?id=60738.