Make ModelForm multiple inheritance is possible.

A reference about form multiple inheritance:

http://www.djangosnippets.org/snippets/703/

After [7846], that this way to make ModelForm? be able to multiple inheritance is invalid.

New way to make it work is:

def getMixupFormMetaClass():
    """
    Get metaclass for form class that inherits multiple forms, especially the
    base classes of form mix up with Form and ModelForm (metaclass mix up with
    DeclarativeFieldsMetaclass, ModelFormMetaclass).
    See http://code.djangoproject.com/ticket/7018 for related details.
    @return Function that will generate class that metaclass will do.
    """
    from django.newforms import models as nmodels
    factory = classmaker()
    def new(name, bases, attrs):
        # get_declared_fields can only be called once, the result will be wrong
        # if you call it again. We call it first to hold the correct result.
        fields = nmodels.get_declared_fields(bases, attrs, True)
        newclass = factory(name, bases, attrs)
        # Restore the correct result.
        newclass.base_fields = fields
        return newclass
    return new

Milestone post-1.0 deleted

It may be nice to have also Form and ModelForm multiple inheritance support. Once case I can think of is having the a user profile ModelForm couple with the Auth UserCreationForm. Illustated below:

class UserProfile(models.Model):
    # This is requred fields for AUTH_PROFILE_MODULE
    user = models.ForeignKey(User, unique=True)

    # User profile information
    age = models.PositiveSmallIntegerField(_("Age"))
    gender = models.CharField(_("Gender"), max_length=1, choices=(
        ('M', _('Male')),
        ('F', _('Female')),
    ))

class MyRegistrationForm(UserCreationForm, forms.ModelForm):
    class Meta:
        model = UserProfile

Given that Django provides a good support user profiles, it may be a good idea to support those profiles' creation in an easy way for fields that a project see as being required for all its users.