If you suddenly start getting a:
PHP Fatal error: Uncaught exception 'GearmanException' with message 'Failed to set exception option' in
...on your GearmanWorker::work() calls, I was able to fix this by specifying values to GearmanWorker::addServer(), even if they are the same as the documented default values.
Crashes:
<?php
$gmw = new GearmanWorker();
$gmw->addServer();
$gmw->work();
?>
Works:
<?php
$gmw = new GearmanWorker();
$gmw->addServer("127.0.0.1", 4730);
$gmw->work();
?>
Go figure. :)