Is there a standard pattern in Rails to unset/reset a model's attributes to previous values or defaults when the user provides something invalid? (In this case I don't want to issue a validation error and ask the user to fix it, I just want to reset to a sensible default)
There's a method for individual attributes. I don't remember the name off the top of my head. It will have _attritbute in the name (I think it's reset_attribute). You could also do http://self.foo = self.previous_foo