opencart/opencart — pull request #1221 by chimeraha (2014-02-19 23:37:12+00:00)
Title: populate $data['custom_field'] in address.php

data['custom_field'] did not exist for some implementation of the addAddress function. And therefore, it wasn't allowing me to continue the checkout process, so I set $data['custom_field'] = '' only if it wasn't set yet.