ModelForm metaclass doesn't remove declared Field attributes

[Daniel Pope <dan@…>]

With normal forms, writing

class FooForm(forms.Form):
    myfoo = forms.CharField()

form = FooForm()

creates a class where form.myfoo gives an attribute error: the CharField is moved to FooForm.base_fields['myfoo'] by the metaclass and deep-copied to form.fields['myfoo'] by the constructor. With an equivalent ModelForm, this doesn't happen and form.myfoo and form.fields['myfoo'] both refer to a CharField instance.

This would be just a slight incompatibility, except that del(form.fields['myfoo']) should remove the field from the form - this is the intended behaviour for standard Forms. With ModelForms, the spurious attribute means that, in a template, {{form.myfoo}} falls back to displaying the repr of the CharField (eg. <django.newforms.fields.CharField object at 0x1fb0a90>) instead of nothing. To delete fields from a ModelForm you need to write

del(form['myfoo'])
del(form.foo)

[Daniel Pope <dan@…>]

Patch to allow get_declared_fields to remove fields from attrs

[Malcolm Tredinnick]

(In [8618]) Fixed #7289 -- Made ModelForms behave like Forms in the sense that Field
objects don't appear as attributes on the final form instance. They continue to
appear as elements of the form_instance.fields mapping.

If you were relying on ModelForms having fields as attributes, then this will
be slightly backwards incompatible. However, normal template usage will see no
change at all.

Patch from Daniel Pope.

[Jacob]

Milestone 1.0 deleted