diff --git a/django/contrib/contenttypes/fields.py b/django/contrib/contenttypes/fields.py index 84aac508142..11afe4df338 100644 --- a/django/contrib/contenttypes/fields.py +++ b/django/contrib/contenttypes/fields.py @@ -237,7 +237,15 @@ class GenericForeignKey(object): pk = rel_obj._meta.pk # If the primary key is a remote field, use the referenced # field's to_python(). - pk_to_python = pk.target_field.to_python if pk.remote_field else pk.to_python + to_python_field = pk + # Out of an abundance of caution, avoid infinite loops. + seen = {to_python_field} + while to_python_field.remote_field: + to_python_field = to_python_field.target_field + if to_python_field in seen: + break + seen.add(to_python_field) + pk_to_python = to_python_field.to_python if pk_to_python(pk_val) != rel_obj._get_pk_val(): rel_obj = None diff --git a/docs/releases/1.11.9.txt b/docs/releases/1.11.9.txt index fa480d44bca..10fe3d9f96b 100644 --- a/docs/releases/1.11.9.txt +++ b/docs/releases/1.11.9.txt @@ -17,3 +17,7 @@ Bugfixes * Fixed incorrect foreign key constraint name for models with quoted ``db_table`` (:ticket:`28876`). + +* Fixed a regression in caching of a ``GenericForeignKey`` when the referenced + model instance uses more than one level of multi-table inheritance + (:ticket:`28856`). diff --git a/tests/generic_relations_regress/models.py b/tests/generic_relations_regress/models.py index 669e7b7186d..5f3b2f849c4 100644 --- a/tests/generic_relations_regress/models.py +++ b/tests/generic_relations_regress/models.py @@ -42,6 +42,12 @@ class Restaurant(Place): return "Restaurant: %s" % self.name +@python_2_unicode_compatible +class Cafe(Restaurant): + def __str__(self): + return "Cafe: %s" % self.name + + @python_2_unicode_compatible class Address(models.Model): street = models.CharField(max_length=80) diff --git a/tests/generic_relations_regress/tests.py b/tests/generic_relations_regress/tests.py index e6d350aa5b1..adb26f68839 100644 --- a/tests/generic_relations_regress/tests.py +++ b/tests/generic_relations_regress/tests.py @@ -5,9 +5,10 @@ from django.forms.models import modelform_factory from django.test import TestCase, skipIfDBFeature from .models import ( - A, Address, B, Board, C, CharLink, Company, Contact, Content, D, Developer, - Guild, HasLinkThing, Link, Node, Note, OddRelation1, OddRelation2, - Organization, Person, Place, Related, Restaurant, Tag, Team, TextLink, + A, Address, B, Board, C, Cafe, CharLink, Company, Contact, Content, D, + Developer, Guild, HasLinkThing, Link, Node, Note, OddRelation1, + OddRelation2, Organization, Person, Place, Related, Restaurant, Tag, Team, + TextLink, ) @@ -53,6 +54,11 @@ class GenericRelationTests(TestCase): CharLink.objects.create(content_object=restaurant) charlink = CharLink.objects.latest('pk') self.assertIs(charlink.content_object, charlink.content_object) + # If the model (Cafe) uses more than one level of multi-table inheritance. + cafe = Cafe.objects.create() + CharLink.objects.create(content_object=cafe) + charlink = CharLink.objects.latest('pk') + self.assertIs(charlink.content_object, charlink.content_object) def test_q_object_or(self): """