Prevent empty querysets to raises AssertionError.

Author: ticosax

rest_framework/permissions.py

@@ -114,7 +114,7 @@ def has_permission(self, request, view):
         if queryset is None and getattr(view, '_ignore_model_permissions', False):
             return True
 
-        assert queryset, (
+        assert queryset is not None, (
             'Cannot apply DjangoModelPermissions on a view that '
             'does not have `.queryset` property.'
         )

tests/test_permissions.py

@@ -31,8 +31,17 @@ class InstanceView(generics.RetrieveUpdateDestroyAPIView):
     authentication_classes = [authentication.BasicAuthentication]
     permission_classes = [permissions.DjangoModelPermissions]
 
+
+class EmptyListView(generics.ListCreateAPIView):
+    queryset = BasicModel.objects.none()
+    serializer_class = BasicSerializer
+    authentication_classes = [authentication.BasicAuthentication]
+    permission_classes = [permissions.DjangoModelPermissions]
+
+
 root_view = RootView.as_view()
 instance_view = InstanceView.as_view()
+empty_list_view = EmptyListView.as_view()
 
 
 def basic_auth_header(username, password):
@@ -149,6 +158,11 @@ def test_options_updateonly(self):
         self.assertIn('actions', response.data)
         self.assertEqual(list(response.data['actions'].keys()), ['PUT'])
 
+    def test_empty_view_does_not_assert(self):
+        request = factory.get('/1', HTTP_AUTHORIZATION=self.permitted_credentials)
+        response = empty_list_view(request, pk=1)
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+
 
 class BasicPermModel(models.Model):
     text = models.CharField(max_length=100)