From 88bb23b506e219983112cc5ca1d63bcb3445da50 Mon Sep 17 00:00:00 2001
From: Diederik van der Boor <vdboor@edoburu.nl>
Date: Thu, 18 Feb 2016 13:14:09 +0100
Subject: [PATCH] Fix deferred loading of 'pk' field

---
 docs/changelog.rst   | 1 +
 polymorphic/query.py | 2 +-
 polymorphic/tests.py | 8 ++++----
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/docs/changelog.rst b/docs/changelog.rst
index 1a61b16..ca89ba4 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -7,6 +7,7 @@ Changes in git
 * Fixed support for ``PolymorphicManager.from_queryset()`` for custom query sets.
 * Fixed Django 1.7 ``changeform_view()`` redirection to the child admin site.
   This fixes custom admin code that uses these views, such as django-reversion_'s ``revision_view()`` / ``recover_view()``.
+* Fixed ``.only('pk')`` field support.
 
 
 Version 0.9 (2016-02-17)
diff --git a/polymorphic/query.py b/polymorphic/query.py
index 0a31f98..1b71bdd 100644
--- a/polymorphic/query.py
+++ b/polymorphic/query.py
@@ -169,7 +169,7 @@ class PolymorphicQuerySet(QuerySet):
         field_names = set(field_names)
         if 'pk' in field_names:
             field_names.remove('pk')
-            field_names.add(self.get_meta().pk.name)
+            field_names.add(self.model._meta.pk.name)
 
         if defer:
             # Remove any existing deferred names from the current set before
diff --git a/polymorphic/tests.py b/polymorphic/tests.py
index 671e445..3e1aa4f 100644
--- a/polymorphic/tests.py
+++ b/polymorphic/tests.py
@@ -569,7 +569,7 @@ class PolymorphicTests(TestCase):
         self.assertEqual(repr(objects_deferred[3]),
             '<Model2D_Deferred_field1: id 4, field1 (CharField), field2 (CharField), field3 (CharField), field4 (CharField)>')
 
-        objects_only = Model2A.objects.only('polymorphic_ctype', 'field1')
+        objects_only = Model2A.objects.only('pk', 'polymorphic_ctype', 'field1')
         self.assertIn('field1', objects_only[0].__dict__,
             'qs.only("field1") was used, but field1 was incorrectly deferred')
         self.assertIn('field1', objects_only[3].__dict__,
@@ -580,13 +580,13 @@ class PolymorphicTests(TestCase):
         self.assertEqual(repr(objects_only[0]),
             '<Model2A: id 1, field1 (CharField)>')
         self.assertEqual(repr(objects_only[1]),
-            '<Model2B_Deferred_field2_id: '
+            '<Model2B_Deferred_field2: '
             'id 2, field1 (CharField), field2 (CharField)>')
         self.assertEqual(repr(objects_only[2]),
-            '<Model2C_Deferred_field2_field3_id_model2a_ptr_id: '
+            '<Model2C_Deferred_field2_field3_model2a_ptr_id: '
             'id 3, field1 (CharField), field2 (CharField), field3 (CharField)>')
         self.assertEqual(repr(objects_only[3]),
-            '<Model2D_Deferred_field2_field3_field4_id_model2a_ptr_id_model2b_ptr_id: '
+            '<Model2D_Deferred_field2_field3_field4_model2a_ptr_id_model2b_ptr_id: '
             'id 4, field1 (CharField), field2 (CharField), field3 (CharField), field4 (CharField)>')
 
     # A bug in Django 1.4 prevents using defer across reverse relations