[1.10.x] Fixed #26667 -- Fixed a regression in queries on a OneToOneField that has to_field and primary_key=True.

Thanks Simon Charette for review.

Backport of e2296e7f0a from master

django/db/models/fields/related_lookups.py

@@ -24,15 +24,16 @@ def get_normalized_value(value, lhs):
     from django.db.models import Model
     if isinstance(value, Model):
         value_list = []
-        # A case like Restaurant.objects.filter(place=restaurant_instance),
-        # where place is a OneToOneField and the primary key of Restaurant.
-        if getattr(lhs.output_field, 'primary_key', False):
-            return (value.pk,)
         sources = lhs.output_field.get_path_info()[-1].target_fields
         for source in sources:
             while not isinstance(value, source.model) and source.remote_field:
                 source = source.remote_field.model._meta.get_field(source.remote_field.field_name)
-            value_list.append(getattr(value, source.attname))
+            try:
+                value_list.append(getattr(value, source.attname))
+            except AttributeError:
+                # A case like Restaurant.objects.filter(place=restaurant_instance),
+                # where place is a OneToOneField and the primary key of Restaurant.
+                return (value.pk,)
         return tuple(value_list)
     if not isinstance(value, tuple):
         return (value,)

docs/releases/1.9.7.txt

@@ -26,3 +26,6 @@ Bugfixes
 
 * Fixed ``dbshell`` crash on PostgreSQL with an empty database name
   (:ticket:`26698`).
+
+* Fixed a regression in queries on a ``OneToOneField`` that has ``to_field``
+  and ``primary_key=True`` (:ticket:`26667`).

tests/one_to_one/models.py

@@ -83,7 +83,7 @@ class MultiModel(models.Model):
 
 
 class Target(models.Model):
-    name = models.CharField(max_length=50)
+    name = models.CharField(max_length=50, unique=True)
 
 
 class Pointer(models.Model):
@@ -98,6 +98,10 @@ class HiddenPointer(models.Model):
     target = models.OneToOneField(Target, models.CASCADE, related_name='hidden+')
 
 
+class ToFieldPointer(models.Model):
+    target = models.OneToOneField(Target, models.CASCADE, to_field='name', primary_key=True)
+
+
 # Test related objects visibility.
 class SchoolManager(models.Manager):
     def get_queryset(self):

tests/one_to_one/tests.py

@@ -6,8 +6,8 @@ from django.utils.deprecation import RemovedInDjango20Warning
 
 from .models import (
     Bar, Director, Favorites, HiddenPointer, ManualPrimaryKey, MultiModel,
-    Place, Pointer, RelatedModel, Restaurant, School, Target, UndergroundBar,
-    Waiter,
+    Place, Pointer, RelatedModel, Restaurant, School, Target, ToFieldPointer,
+    UndergroundBar, Waiter,
 )
 
 
@@ -530,3 +530,9 @@ class OneToOneTests(TestCase):
         r = Restaurant.objects.first()
         r2 = Restaurant.objects.filter(pk__exact=r).first()
         self.assertEqual(r, r2)
+
+    def test_primary_key_to_field_filter(self):
+        target = Target.objects.create(name='foo')
+        pointer = ToFieldPointer.objects.create(target=target)
+        self.assertQuerysetEqual(ToFieldPointer.objects.filter(target=target), [pointer], lambda x: x)
+        self.assertQuerysetEqual(ToFieldPointer.objects.filter(pk__exact=pointer), [pointer], lambda x: x)