pear/pear-core — pull request #3 by ftzdomino (2011-12-16 22:48:48+00:00)
Title: Fixing a major error with PEAR::isError() and PHP 5.3.7+

is_a() now triggers an autoload for the class it's a string, so PEAR::isError($data) where $data is a string causes an autoload/class not found error.