Commit 384ddbec authored by Tim Graham's avatar Tim Graham
Browse files

Fixed #14368 -- Allowed setting a reverse OneToOne relation to None.

parent 5d898500

django/db/models/fields/related_descriptors.py

+28 −18
Original line number Diff line number Diff line
@@ -376,14 +376,24 @@ class ReverseOneToOneDescriptor(object): 


        # If null=True, we can assign null here, but otherwise the value needs

        # to be an instance of the related class.

        if value is None and self.related.field.null is False:

        if value is None:

            if self.related.field.null:

                # Update the cached related instance (if any) & clear the cache.

                try:

                    rel_obj = getattr(instance, self.cache_name)

                except AttributeError:

                    pass

                else:

                    delattr(instance, self.cache_name)

                    setattr(rel_obj, self.related.field.name, None)

            else:

                raise ValueError(

                    'Cannot assign None: "%s.%s" does not allow null values.' % (

                        instance._meta.object_name,

                        self.related.get_accessor_name(),

                    )

                )

        elif value is not None and not isinstance(value, self.related.related_model):

        elif not isinstance(value, self.related.related_model):

            raise ValueError(

                'Cannot assign "%r": "%s.%s" must be a "%s" instance.' % (

                    value,
@@ -392,7 +402,7 @@ class ReverseOneToOneDescriptor(object): 
                    self.related.related_model._meta.object_name,

                )

            )

        elif value is not None:

        else:

            if instance._state.db is None:

                instance._state.db = router.db_for_write(instance.__class__, instance=value)

            elif value._state.db is None:

tests/one_to_one/tests.py

+16 −0
Original line number Diff line number Diff line
@@ -186,6 +186,22 @@ class OneToOneTests(TestCase): 
        self.assertEqual(self.p1.restaurant, self.r1)

        self.assertEqual(self.p1.bar, self.b1)



    def test_assign_none_reverse_relation(self):

        p = Place.objects.get(name="Demon Dogs")

        # Assigning None succeeds if field is null=True.

        ug_bar = UndergroundBar.objects.create(place=p, serves_cocktails=False)

        p.undergroundbar = None

        self.assertIsNone(ug_bar.place)

        ug_bar.save()

        ug_bar.refresh_from_db()

        self.assertIsNone(ug_bar.place)



    def test_assign_none_null_reverse_relation(self):

        p = Place.objects.get(name="Demon Dogs")

        # Assigning None doesn't throw AttributeError if there isn't a related

        # UndergroundBar.

        p.undergroundbar = None



    def test_related_object_cache(self):

        """ Regression test for #6886 (the related-object cache) """