Fixed #13811 -- Changed unique validation in model formsets to ignore None...

                # it's already invalid

                if not hasattr(form, "cleaned_data"):

                    continue

                # get each of the fields for which we have data on this form

                if [f for f in unique_check if f in form.cleaned_data and form.cleaned_data[f] is not None]:

                    # get the data itself

                    row_data = tuple([form.cleaned_data[field] for field in unique_check])

                # get data for each field of each of unique_check

                row_data = tuple([form.cleaned_data[field] for field in unique_check if field in form.cleaned_data])

                if row_data and not None in row_data:

                    # if we've aready seen it then we have a uniqueness failure

                    if row_data in seen_data:

                        # poke error messages into the right places and mark

    def __unicode__(self):

        return u'%s: %s' % (self.my_pk, self.title)

class Editor(models.Model):

    name = models.CharField(max_length=100)

class BookWithOptionalAltEditor(models.Model):

    author = models.ForeignKey(Author)

    # Optional secondary author

    alt_editor = models.ForeignKey(Editor, blank=True, null=True)

    title = models.CharField(max_length=100)

    class Meta:

        unique_together = (

            ('author', 'title', 'alt_editor'),

        )

    def __unicode__(self):

        return self.title

class AlternateBook(Book):

    notes = models.CharField(max_length=100)

>>> formset.save()

[<AlternateBook: Flowers of Evil - English translation of Les Fleurs du Mal>]

Test inline formsets where the inline-edited object has a unique_together constraint with a nullable member

>>> AuthorBooksFormSet4 = inlineformset_factory(Author, BookWithOptionalAltEditor, can_delete=False, extra=2)

>>> data = {

...     'bookwithoptionalalteditor_set-TOTAL_FORMS': '2', # the number of forms rendered

...     'bookwithoptionalalteditor_set-INITIAL_FORMS': '0', # the number of forms with initial data

...     'bookwithoptionalalteditor_set-MAX_NUM_FORMS': '', # the max number of forms

...     'bookwithoptionalalteditor_set-0-author': '1',

...     'bookwithoptionalalteditor_set-0-title': 'Les Fleurs du Mal',

...     'bookwithoptionalalteditor_set-1-author': '1',

...     'bookwithoptionalalteditor_set-1-title': 'Les Fleurs du Mal',

... }

>>> formset = AuthorBooksFormSet4(data, instance=author)

>>> formset.is_valid()

True

>>> formset.save()

[<BookWithOptionalAltEditor: Les Fleurs du Mal>, <BookWithOptionalAltEditor: Les Fleurs du Mal>]

# ModelForm with a custom save method in an inline formset ###################