2010/1/10 Tai Lee <real.hu...@mrmachine.net> > On Jan 9, 12:36 am, Honza Král <honza.k...@gmail.com> wrote: > > On Fri, Jan 8, 2010 at 11:59 AM, koenb <koen.bierm...@werk.belgie.be> > wrote: > > > > > On 8 jan, 10:03, James Bennett <ubernost...@gmail.com> wrote: > > > > >> Suppose I have a ModelForm and call save(commit=False) to get the > > >> instance so I can do some more work on it. I'm basically saying to > > >> Django "I don't think this object is ready to be saved yet, but I need > > >> the object so I can do stuff to it". If Django goes ahead and does > > >> implicit model validation there and raises an exception, it's just > > >> telling me what I already knew: the object's not ready to be saved. > > >> But now I get to do extra work to catch the exception, and that's bad > > >> and wrong. > > > > >> Calling ModelForm.save(commit=False) should simply disable model > > >> validation, period. If I want to validate the instance before saving > > >> it, I'll validate the instance before saving it, but commit=False is > > >> as clear a way as we have of saying "I'm not going to save this yet" > > >> and model validation should respect that. > > I agree with this completely. Calling ModelForm.save(commit=False) > should disable model validation, period. We're explicitly telling > Django not to save the model because it's not ready to be saved, > therefore no model validation needs to be performed. > > > > The problem is that in the idiom the is_valid() call on the modelform > > > tries to full_validate the instance, it is not in the save > > > (commit=False) call. > > > > Yes > > This is what I think should be changed. ModelForm.is_valid() should > only validate the form. Model validation errors should not be (and I > believe are not currently) returned to the user as form errors, > because they're not form errors and the user can't do anything about > them.
This is only true as long as we're talking about simple validators. If there are constraints on the model that include more then one field - one which comes from the form + a generated one - then returning it as an error may be useful. Only validating the form is probably a good strategy, but I think there should be an easy way of returning model validation errors to the user. > They're errors for the developer at the point when he or she is > ready to save a model. Model validation should be moved out of > ModelForm.is_valid() and into ModelForm.save(), but only if > `commit=True`. Otherwise, model validation should be performed when > explicitly requested. > > Cheers. > Tai. > > -- > You received this message because you are subscribed to the Google Groups > "Django developers" group. > To post to this group, send email to django-develop...@googlegroups.com. > To unsubscribe from this group, send email to > django-developers+unsubscr...@googlegroups.com<django-developers%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/django-developers?hl=en. > > -- Łukasz Rekucki--
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