Fixed #23616 - Fixed generic relations in ModelAdmin.list_filter.

Thanks ranjur for reporting bug, timgraham for review,
and collinanderson for contributing tips.

django/contrib/admin/options.py

@@ -417,7 +417,10 @@ class BaseModelAdmin(six.with_metaclass(forms.MediaDefiningClass)):
                     # since it's ignored in ChangeList.get_filters().
                     return True
                 model = field.rel.to
-                rel_name = field.rel.get_related_field().name
+                if hasattr(field.rel, 'get_related_field'):
+                    rel_name = field.rel.get_related_field().name
+                else:
+                    rel_name = None
             elif isinstance(field, RelatedObject):
                 model = field.model
                 rel_name = model._meta.pk.name

docs/releases/1.7.1.txt

@@ -113,3 +113,5 @@ Bugfixes
 * Added a prompt to the migrations questioner when removing the null constraint
   from a field to prevent an IntegrityError on existing NULL rows
   (:ticket:`23609`).
+
+* Fixed generic relations in ``ModelAdmin.list_filter`` (:ticket:`23616`).

tests/admin_filters/models.py

@@ -1,6 +1,8 @@
 from __future__ import unicode_literals
 
 from django.contrib.auth.models import User
+from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
+from django.contrib.contenttypes.models import ContentType
 from django.db import models
 from django.utils.encoding import python_2_unicode_compatible
 
@@ -35,3 +37,23 @@ class Employee(models.Model):
 
     def __str__(self):
         return self.name
+
+
+@python_2_unicode_compatible
+class TaggedItem(models.Model):
+    tag = models.SlugField()
+    content_type = models.ForeignKey(ContentType, related_name='tagged_items')
+    object_id = models.PositiveIntegerField()
+    content_object = GenericForeignKey('content_type', 'object_id')
+
+    def __str__(self):
+        return self.tag
+
+
+@python_2_unicode_compatible
+class Bookmark(models.Model):
+    url = models.URLField()
+    tags = GenericRelation(TaggedItem)
+
+    def __str__(self):
+        return self.url

tests/admin_filters/tests.py

@@ -12,7 +12,7 @@ from django.test import TestCase, RequestFactory, override_settings
 from django.utils.encoding import force_text
 from django.utils import six
 
-from .models import Book, Department, Employee
+from .models import Book, Department, Employee, Bookmark, TaggedItem
 
 
 def select_by(dictlist, key, value):
@@ -205,6 +205,10 @@ class DepartmentFilterDynamicValueBookAdmin(EmployeeAdmin):
     list_filter = [DepartmentListFilterLookupWithDynamicValue, ]
 
 
+class BookmarkAdminGenericRelation(ModelAdmin):
+    list_filter = ['tags__tag']
+
+
 class ListFiltersTests(TestCase):
 
     def setUp(self):
@@ -539,6 +543,24 @@ class ListFiltersTests(TestCase):
         expected = [(self.bob.pk, 'bob'), (self.lisa.pk, 'lisa')]
         self.assertEqual(sorted(filterspec.lookup_choices), sorted(expected))
 
+    def test_listfilter_genericrelation(self):
+        django_bookmark = Bookmark.objects.create(url='https://www.djangoproject.com/')
+        python_bookmark = Bookmark.objects.create(url='https://www.python.org/')
+        kernel_bookmark = Bookmark.objects.create(url='https://www.kernel.org/')
+
+        TaggedItem.objects.create(content_object=django_bookmark, tag='python')
+        TaggedItem.objects.create(content_object=python_bookmark, tag='python')
+        TaggedItem.objects.create(content_object=kernel_bookmark, tag='linux')
+
+        modeladmin = BookmarkAdminGenericRelation(Bookmark, site)
+
+        request = self.request_factory.get('/', {'tags__tag': 'python'})
+        changelist = self.get_changelist(request, Bookmark, modeladmin)
+        queryset = changelist.get_queryset(request)
+
+        expected = [python_bookmark, django_bookmark]
+        self.assertEqual(list(queryset), expected)
+
     def test_booleanfieldlistfilter(self):
         modeladmin = BookAdmin(Book, site)
         self.verify_booleanfieldlistfilter(modeladmin)