tangentlabs/django-oscar — pull request #584 by maikhoepfel (2013-03-26 10:30:54+00:00)
Title: Many CharFields have null=True set

That is [discouraged](https://docs.djangoproject.com/en/dev/ref/models/fields/#null) as it means two possible states for empty data. There's a limited amount of use cases for it, but given the widespread usage, I'd say that's a bug.