Fix the way DjangoModelPermissions asks for the model to be checked.

rest_framework/permissions.py

@@ -184,13 +184,15 @@ class DjangoModelPermissions(BasePermission):
             '`.queryset` or have a `.get_queryset()` method.'
         ).format(self.__class__.__name__)
 
-        if hasattr(view, 'get_queryset'):
+        queryset = getattr(view, 'queryset', None)
+
+        if queryset is None:
             queryset = view.get_queryset()
             assert queryset is not None, (
-                '{}.get_queryset() returned None'.format(view.__class__.__name__)
+                'The value of {0}.queryset and {0}.get_queryset() is None.'.format(view.__class__.__name__)
             )
-            return queryset
-        return view.queryset
+
+        return queryset
 
     def has_permission(self, request, view):
         # Workaround to ensure DjangoModelPermissions are not applied

tests/test_permissions.py

@@ -236,12 +236,14 @@ class ModelPermissionsIntegrationTests(TestCase):
 
         # Faulty `get_queryset()` methods should trigger the above "view does not have a queryset" assertion.
         class View(RootView):
+            queryset = None
+
             def get_queryset(self):
                 return None
         view = View.as_view()
 
         request = factory.get('/', HTTP_AUTHORIZATION=self.permitted_credentials)
-        with self.assertRaisesMessage(AssertionError, 'View.get_queryset() returned None'):
+        with self.assertRaisesMessage(AssertionError, 'The value of View.queryset and View.get_queryset() is None.'):
             view(request)
 
 
@@ -589,3 +591,4 @@ class PermissionsCompositionTests(TestCase):
             permissions.IsAuthenticated
         )
         assert composed_perm().has_permission(request, None) is True
+