Refs #26320 -- Removed implicit OneToOnField parent_link per deprecation timeline.

django/db/models/options.py

@@ -8,7 +8,7 @@ from itertools import chain
 
 from django.apps import apps
 from django.conf import settings
-from django.core.exceptions import FieldDoesNotExist
+from django.core.exceptions import FieldDoesNotExist, ImproperlyConfigured
 from django.db import connections
 from django.db.models import Manager
 from django.db.models.fields import AutoField
@@ -244,9 +244,8 @@ class Options(object):
                 field.primary_key = True
                 self.setup_pk(field)
                 if not field.remote_field.parent_link:
-                    warnings.warn(
-                        'Add parent_link=True to %s as an implicit link is '
-                        'deprecated.' % field, RemovedInDjango20Warning
+                    raise ImproperlyConfigured(
+                        'Add parent_link=True to %s.' % field,
                     )
             else:
                 auto = AutoField(verbose_name='ID', primary_key=True, auto_created=True)

docs/releases/2.0.txt

@@ -370,3 +370,6 @@ these features.
 * The ``javascript_catalog()`` and ``json_catalog()`` views are removed.
 
 * ``django.contrib.gis.utils.precision_wkt()`` is removed.
+
+* In multi-table inheritance, implicit promotion of a ``OneToOneField`` to a
+  ``parent_link`` is removed.

tests/invalid_models_tests/test_models.py

@@ -2,11 +2,11 @@
 from __future__ import unicode_literals
 
 import unittest
-import warnings
 
 from django.conf import settings
 from django.core.checks import Error
 from django.core.checks.model_checks import _check_lazy_references
+from django.core.exceptions import ImproperlyConfigured
 from django.db import connections, models
 from django.db.models.signals import post_init
 from django.test import SimpleTestCase
@@ -783,26 +783,14 @@ class OtherModelTests(SimpleTestCase):
         self.assertEqual(errors, expected)
 
     def test_missing_parent_link(self):
-        with warnings.catch_warnings(record=True) as warns:
-            warnings.simplefilter('always')
-
+        msg = 'Add parent_link=True to invalid_models_tests.ParkingLot.parent.'
+        with self.assertRaisesMessage(ImproperlyConfigured, msg):
             class Place(models.Model):
                 pass
 
             class ParkingLot(Place):
-                # In lieu of any other connector, an existing OneToOneField will be
-                # promoted to the primary key.
                 parent = models.OneToOneField(Place, models.CASCADE)
 
-        self.assertEqual(len(warns), 1)
-        msg = str(warns[0].message)
-        self.assertEqual(
-            msg,
-            'Add parent_link=True to invalid_models_tests.ParkingLot.parent '
-            'as an implicit link is deprecated.'
-        )
-        self.assertEqual(ParkingLot._meta.pk.name, 'parent')
-
     def test_m2m_table_name_clash(self):
         class Foo(models.Model):
             bar = models.ManyToManyField('Bar', db_table='myapp_bar')