Only use object permissions in browsable api form generation if an object exists

Author: tomchristie

rest_framework/renderers.py

@@ -349,7 +349,8 @@ def show_form_for_method(self, view, method, request, obj):
 
         try:
             view.check_permissions(request)
-            view.check_object_permissions(request, obj)
+            if obj is not None:
+                view.check_object_permissions(request, obj)
         except exceptions.APIException:
             return False  # Doesn't have permissions
         return True