Fixed #23641 -- Moved post_migrate signals for contrib apps to AppConfig.ready().

django/contrib/auth/apps.py

@@ -1,13 +1,17 @@
 from django.apps import AppConfig
 from django.core import checks
 from django.contrib.auth.checks import check_user_model
-
+from django.db.models.signals import post_migrate
 from django.utils.translation import ugettext_lazy as _
 
+from .management import create_permissions
+
 
 class AuthConfig(AppConfig):
     name = 'django.contrib.auth'
     verbose_name = _("Authentication and Authorization")
 
     def ready(self):
+        post_migrate.connect(create_permissions,
+            dispatch_uid="django.contrib.auth.management.create_permissions")
         checks.register(check_user_model, checks.Tags.models)

django/contrib/auth/management/__init__.py

@@ -7,11 +7,10 @@ import getpass
 import unicodedata
 
 from django.apps import apps
-from django.contrib.auth import models as auth_app, get_permission_codename
+from django.contrib.auth import get_permission_codename
 from django.core import exceptions
 from django.core.management.base import CommandError
 from django.db import DEFAULT_DB_ALIAS, router
-from django.db.models import signals
 from django.utils.encoding import DEFAULT_LOCALE_ENCODING
 from django.utils import six
 
@@ -149,6 +148,9 @@ def get_default_username(check_db=True):
     :returns: The username, or an empty string if no username can be
         determined.
     """
+    # This file is used in apps.py, it should not trigger models import.
+    from django.contrib.auth import models as auth_app
+
     # If the User model has been swapped out, we can't make any assumptions
     # about the default user name.
     if auth_app.User._meta.swapped:
@@ -177,7 +179,3 @@ def get_default_username(check_db=True):
         else:
             return ''
     return default_username
-
-
-signals.post_migrate.connect(create_permissions,
-    dispatch_uid="django.contrib.auth.management.create_permissions")

django/contrib/contenttypes/apps.py

@@ -1,12 +1,16 @@
 from django.apps import AppConfig
 from django.contrib.contenttypes.checks import check_generic_foreign_keys
 from django.core import checks
+from django.db.models.signals import post_migrate
 from django.utils.translation import ugettext_lazy as _
 
+from .management import update_contenttypes
+
 
 class ContentTypesConfig(AppConfig):
     name = 'django.contrib.contenttypes'
     verbose_name = _("Content Types")
 
     def ready(self):
+        post_migrate.connect(update_contenttypes)
         checks.register(check_generic_foreign_keys, checks.Tags.models)

django/contrib/contenttypes/management.py

@@ -1,6 +1,5 @@
 from django.apps import apps
 from django.db import DEFAULT_DB_ALIAS, router
-from django.db.models import signals
 from django.utils.encoding import smart_text
 from django.utils import six
 from django.utils.six.moves import input
@@ -92,8 +91,5 @@ def update_all_contenttypes(**kwargs):
         update_contenttypes(app_config, **kwargs)
 
 
-signals.post_migrate.connect(update_contenttypes)
-
-
 if __name__ == "__main__":
     update_all_contenttypes()

django/contrib/sites/apps.py

@@ -1,8 +1,14 @@
 from django.apps import AppConfig
 
+from django.db.models.signals import post_migrate
 from django.utils.translation import ugettext_lazy as _
 
+from .management import create_default_site
+
 
 class SitesConfig(AppConfig):
     name = 'django.contrib.sites'
     verbose_name = _("Sites")
+
+    def ready(self):
+        post_migrate.connect(create_default_site, sender=self)

django/contrib/sites/management.py

@@ -5,7 +5,6 @@ Creates the default Site object.
 from django.apps import apps
 from django.core.management.color import no_style
 from django.db import DEFAULT_DB_ALIAS, connections, router
-from django.db.models import signals
 
 
 def create_default_site(app_config, verbosity=2, interactive=True, db=DEFAULT_DB_ALIAS, **kwargs):
@@ -38,6 +37,3 @@ def create_default_site(app_config, verbosity=2, interactive=True, db=DEFAULT_DB
                     cursor.execute(command)
 
         Site.objects.clear_cache()
-
-
-signals.post_migrate.connect(create_default_site, sender=apps.get_app_config('sites'))

django/contrib/sites/tests.py

@@ -1,7 +1,9 @@
 from __future__ import unicode_literals
 
+from django.apps import apps
 from django.conf import settings
 from django.core.exceptions import ObjectDoesNotExist, ValidationError
+from django.db.models.signals import post_migrate
 from django.http import HttpRequest
 from django.test import TestCase, modify_settings, override_settings
 
@@ -118,6 +120,15 @@ class SitesFrameworkTests(TestCase):
         clear_site_cache(Site, instance=self.site)
         self.assertEqual(models.SITE_CACHE, {})
 
+    def test_create_default_site_signal(self):
+        """
+        Checks that sending ``post_migrate`` creates the default site.
+        """
+        Site.objects.all().delete()
+        app_config = apps.get_app_config('sites')
+        post_migrate.send(sender=app_config, app_config=app_config, verbosity=0)
+        self.assertTrue(Site.objects.exists())
+
 
 class MiddlewareTest(TestCase):