Fixed #24328 -- cleaned up Options._get_fields() implementation

django/db/models/base.py

@@ -239,7 +239,8 @@ class ModelBase(type):
             else:
                 # .. and abstract ones.
                 for field in parent_fields:
-                    new_class.add_to_class(field.name, copy.deepcopy(field))
+                    new_field = copy.deepcopy(field)
+                    new_class.add_to_class(field.name, new_field)
 
                 # Pass any non-abstract parent classes onto child.
                 new_class._meta.parents.update(base._meta.parents)

tests/model_meta/tests.py

@@ -228,11 +228,9 @@ class RelationTreeTests(TestCase):
             sorted([field.related_query_name() for field in Relation._meta._relation_tree
                    if not field.rel.field.rel.is_hidden()]),
             sorted([
-                'fk_abstract_rel', 'fk_abstract_rel', 'fk_abstract_rel', 'fk_base_rel', 'fk_base_rel',
-                'fk_base_rel', 'fk_concrete_rel', 'fk_concrete_rel', 'fo_abstract_rel', 'fo_abstract_rel',
-                'fo_abstract_rel', 'fo_base_rel', 'fo_base_rel', 'fo_base_rel', 'fo_concrete_rel',
-                'fo_concrete_rel', 'm2m_abstract_rel', 'm2m_abstract_rel', 'm2m_abstract_rel',
-                'm2m_base_rel', 'm2m_base_rel', 'm2m_base_rel', 'm2m_concrete_rel', 'm2m_concrete_rel',
+                'fk_abstract_rel', 'fk_base_rel', 'fk_concrete_rel', 'fo_abstract_rel',
+                'fo_base_rel', 'fo_concrete_rel', 'm2m_abstract_rel',
+                'm2m_base_rel', 'm2m_concrete_rel'
             ])
         )
         # Testing hidden related objects
@@ -243,9 +241,8 @@ class RelationTreeTests(TestCase):
                 'BasePerson_following_base+', 'BasePerson_following_base+', 'BasePerson_friends_abstract+',
                 'BasePerson_friends_abstract+', 'BasePerson_friends_base+', 'BasePerson_friends_base+',
                 'BasePerson_m2m_abstract+', 'BasePerson_m2m_base+', 'Relating_basepeople+',
-                'Relating_basepeople_hidden+', 'followers_abstract', 'followers_abstract', 'followers_abstract',
-                'followers_base', 'followers_base', 'followers_base', 'friends_abstract_rel_+', 'friends_abstract_rel_+',
-                'friends_abstract_rel_+', 'friends_base_rel_+', 'friends_base_rel_+', 'friends_base_rel_+', 'person',
+                'Relating_basepeople_hidden+', 'followers_abstract',
+                'followers_base', 'friends_abstract_rel_+', 'friends_base_rel_+',
                 'person', 'relating_basepeople', 'relating_baseperson',
             ])
         )

tests/proxy_models/models.py

@@ -158,7 +158,7 @@ class ProxyTrackerUser(TrackerUser):
 @python_2_unicode_compatible
 class Issue(models.Model):
     summary = models.CharField(max_length=255)
-    assignee = models.ForeignKey(TrackerUser)
+    assignee = models.ForeignKey(ProxyTrackerUser)
 
     def __str__(self):
         return ':'.join((self.__class__.__name__, self.summary,))

tests/proxy_models/tests.py

@@ -3,7 +3,7 @@ from __future__ import unicode_literals
 from django.apps import apps
 from django.contrib import admin
 from django.contrib.contenttypes.models import ContentType
-from django.core import checks, management
+from django.core import checks, exceptions, management
 from django.core.urlresolvers import reverse
 from django.db import DEFAULT_DB_ALIAS, models
 from django.db.models import signals
@@ -328,8 +328,18 @@ class ProxyModelTests(TestCase):
         resp = StateProxy.objects.select_related().get(name='New South Wales')
         self.assertEqual(resp.name, 'New South Wales')
 
+    def test_filter_proxy_relation_reverse(self):
+        tu = TrackerUser.objects.create(
+            name='Contributor', status='contrib')
+        with self.assertRaises(exceptions.FieldError):
+            TrackerUser.objects.filter(issue=None),
+        self.assertQuerysetEqual(
+            ProxyTrackerUser.objects.filter(issue=None),
+            [tu], lambda x: x
+        )
+
     def test_proxy_bug(self):
-        contributor = TrackerUser.objects.create(name='Contributor',
+        contributor = ProxyTrackerUser.objects.create(name='Contributor',
             status='contrib')
         someone = BaseUser.objects.create(name='Someone')
         Bug.objects.create(summary='fix this', version='1.1beta',