contrib/admin/options.py add_view, change_view

[tangc]

add_view, change_view has the following code:

ModelForm = self.get_form(request)
...

form = ModelForm(request.POST, request.FILES)

or

form = ModelForm(initial=initial)

or

form = ModelForm(request.POST, request.FILES, instance=obj)

I would propose:

if isinstance(ModelForm, ModelFormMetaclass):

form = ModelForm(request.POST, request.FILES)

else

form = ModelForm

This way gives the flexibility to override the function get_form(self, request, obj=None, kwargs), which could return a modelform_factory(self.model, defaults) or an instance of a model form.