From 30630647c4edfb644cc8c03edf4838058ca83d8f Mon Sep 17 00:00:00 2001
From: Diederik van der Boor <vdboor@edoburu.nl>
Date: Sat, 30 Sep 2017 20:26:52 +0200
Subject: [PATCH] Add extra comment why deferred fields are skipped with ___
 lookups

---
 polymorphic/query.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/polymorphic/query.py b/polymorphic/query.py
index 454c526..97fc21a 100644
--- a/polymorphic/query.py
+++ b/polymorphic/query.py
@@ -393,6 +393,9 @@ class PolymorphicQuerySet(QuerySet):
                         # now a superclass of real_concrete_class. Thus it's
                         # sufficient to just use the field name.
                         translated_field_name = field.rpartition('___')[-1]
+
+                        # Check if the field does exist.
+                        # Ignore deferred fields that don't exist in this subclass type.
                         try:
                             real_concrete_class._meta.get_field(translated_field_name)
                         except FieldDoesNotExist: