Fixed #24395 -- Ensured inline ModelsForms have an updated related instance.

        return cls.fk.rel.get_accessor_name(model=cls.model).replace('+', '')

    def save_new(self, form, commit=True):

        # Ensure the latest copy of the related instance is present on each

        # form (it may have been saved after the formset was originally

        # instantiated).

        setattr(form.instance, self.fk.name, self.instance)

        # Use commit=False so we can assign the parent key afterwards, then

        # save the object.

        obj = form.save(commit=False)

        formset = AuthorBooksFormSet(data, instance=author, queryset=custom_qs)

        self.assertTrue(formset.is_valid())

    def test_inline_formsets_with_custom_save_method_related_instance(self):

        """

        The ModelForm.save() method should be able to access the related object

        if it exists in the database (#24395).

        """

        class PoemForm2(forms.ModelForm):

            def save(self, commit=True):

                poem = super(PoemForm2, self).save(commit=False)

                poem.name = "%s by %s" % (poem.name, poem.poet.name)

                if commit:

                    poem.save()

                return poem

        PoemFormSet = inlineformset_factory(Poet, Poem, form=PoemForm2, fields="__all__")

        data = {

            'poem_set-TOTAL_FORMS': '1',

            'poem_set-INITIAL_FORMS': '0',

            'poem_set-MAX_NUM_FORMS': '',

            'poem_set-0-name': 'Le Lac',

        }

        poet = Poet()

        formset = PoemFormSet(data=data, instance=poet)

        self.assertTrue(formset.is_valid())

        # The Poet instance is saved after the formset instantiation. This

        # happens in admin's changeform_view() when adding a new object and

        # some inlines in the same request.

        poet.name = 'Lamartine'

        poet.save()

        poem = formset.save()[0]

        self.assertEqual(poem.name, 'Le Lac by Lamartine')

    def test_inline_formsets_with_wrong_fk_name(self):

        """ Regression for #23451 """

        message = "fk_name 'title' is not a ForeignKey to 'model_formsets.Author'."