stephenmcd/cartridge — pull request #150 by kklimonda (2013-12-10 21:29:08+00:00)
Title: Chain up to the parent's clean() method when needed.

ModelForm and BaseInlineFormSet do some extra unique validation before
saving model to the database. Not doing that may result in IntegrityError being raised.

That can happen for example when user tries to set two ProductVariation SKUs to the same value.