Fixed #21712 -- Moved autodiscover() to AdminConfig.ready().

Thanks Marc Tamlyn for the initial version of the patch.

django/conf/project_template/project_name/settings.py

@@ -30,7 +30,7 @@ ALLOWED_HOSTS = []
 # Application definition
 
 INSTALLED_APPS = (
-    'django.contrib.admin',
+    'django.contrib.admin.apps.AdminConfig',
     'django.contrib.auth',
     'django.contrib.contenttypes',
     'django.contrib.sessions',

django/conf/project_template/project_name/urls.py

@@ -1,7 +1,5 @@
 from django.conf.urls import patterns, include, url
-
 from django.contrib import admin
-admin.autodiscover()
 
 urlpatterns = patterns('',
     # Examples:

django/contrib/admin/apps.py

@@ -6,3 +6,6 @@ from django.utils.translation import ugettext_lazy as _
 class AdminConfig(AppConfig):
     name = 'django.contrib.admin'
     verbose_name = _("administration")
+
+    def ready(self):
+        self.module.autodiscover()

django/contrib/admin/sites.py

@@ -161,8 +161,8 @@ class AdminSite(object):
         installed, as well as the auth context processor.
         """
         if not apps.is_installed('django.contrib.admin'):
-            raise ImproperlyConfigured("Put 'django.contrib.admin' in your "
-                "INSTALLED_APPS setting in order to use the admin application.")
+            raise ImproperlyConfigured("Put 'django.contrib.admin.apps.AdminConfig' in "
+                "your INSTALLED_APPS setting in order to use the admin application.")
         if not apps.is_installed('django.contrib.contenttypes'):
             raise ImproperlyConfigured("Put 'django.contrib.contenttypes' in "
                 "your INSTALLED_APPS setting in order to use the admin application.")

docs/intro/tutorial01.txt

@@ -435,7 +435,7 @@ look like this:
     :filename: mysite/settings.py
 
     INSTALLED_APPS = (
-        'django.contrib.admin',
+        'django.contrib.admin.apps.AdminConfig',
         'django.contrib.auth',
         'django.contrib.contenttypes',
         'django.contrib.sessions',
@@ -444,6 +444,13 @@ look like this:
         'polls',
     )
 
+.. admonition:: Doesn't match what you see?
+
+    If you're seeing ``'django.contrib.admin'`` instead of
+    ``'django.contrib.admin.apps.AdminConfig'``, you're probably using a
+    version of Django that doesn't match this tutorial version.  You'll want
+    to either switch to the older tutorial or the newer Django version.
+
 Now Django knows to include the ``polls`` app. Let's run another command:
 
 .. code-block:: bash

docs/intro/tutorial03.txt

@@ -105,15 +105,20 @@ with:
     :filename: mysite/urls.py
 
     from django.conf.urls import patterns, include, url
-
     from django.contrib import admin
-    admin.autodiscover()
 
     urlpatterns = patterns('',
         url(r'^polls/', include('polls.urls')),
         url(r'^admin/', include(admin.site.urls)),
     )
 
+.. admonition:: Doesn't match what you see?
+
+    If you're seeing ``admin.autodiscover()`` before the definition of
+    ``urlpatterns``, you're probably using a version of Django that doesn't
+    match this tutorial version.  You'll want to either switch to the older
+    tutorial or the newer Django version.
+
 You have now wired an ``index`` view into the URLconf. Go to
 http://localhost:8000/polls/ in your browser, and you should see the text
 "*Hello, world. You're at the polls index.*", which you defined in the
@@ -587,9 +592,7 @@ it to include namespacing:
     :filename: mysite/urls.py
 
     from django.conf.urls import patterns, include, url
-
     from django.contrib import admin
-    admin.autodiscover()
 
     urlpatterns = patterns('',
         url(r'^polls/', include('polls.urls', namespace="polls")),

docs/ref/contrib/admin/index.txt

@@ -23,8 +23,12 @@ The admin is enabled in the default project template used by
 
 For reference, here are the requirements:
 
-1. Add ``'django.contrib.admin'`` to your :setting:`INSTALLED_APPS`
-   setting.
+1. Add ``'django.contrib.admin.apps.AdminConfig'`` to your
+   :setting:`INSTALLED_APPS` setting.
+
+   .. versionchanged:: 1.7
+
+       :setting:`INSTALLED_APPS` used to contain ``'django.contrib.admin'``.
 
 2. The admin has four dependencies - :mod:`django.contrib.auth`,
    :mod:`django.contrib.contenttypes`,
@@ -76,7 +80,7 @@ Other topics
 .. class:: ModelAdmin
 
     The ``ModelAdmin`` class is the representation of a model in the admin
-    interface. These are stored in a file named ``admin.py`` in your
+    interface. Usually, these are stored in a file named ``admin.py`` in your
     application. Let's take a look at a very simple example of
     the ``ModelAdmin``::
 
@@ -129,6 +133,36 @@ The register decorator
         class PersonAdmin(admin.ModelAdmin):
             pass
 
+Discovery of admin files
+------------------------
+
+The admin needs to be instructed to look for ``admin.py`` files in your project.
+The easiest solution is to put ``'django.contrib.admin.apps.AdminConfig'`` in
+your :setting:`INSTALLED_APPS` setting.
+
+.. class:: django.contrib.admin.apps.AdminConfig
+
+    .. versionadded:: 1.7
+
+    This class calls :func:`~django.contrib.admin.autodiscover()` when Django
+    starts.
+
+.. function:: django.contrib.admin.autodiscover
+
+    This function attempts to import an ``admin`` module in each installed
+    application. Such modules are expected to register models with the admin.
+
+    .. versionchanged:: 1.7
+
+        Previous versions of Django recommended calling this function directly
+        in the URLconf. :class:`~django.contrib.admin.apps.AdminConfig`
+        replaces that mechanism and is more robust.
+
+If you are using a custom ``AdminSite``, it is common to import all of the
+``ModelAdmin`` subclasses into your code and register them to the custom
+``AdminSite``. In that case, simply put ``'django.contrib.admin'`` in your
+:setting:`INSTALLED_APPS` setting, as you don't need autodiscovery.
+
 ``ModelAdmin`` options
 ----------------------
 
@@ -2377,15 +2411,10 @@ In this example, we register the default ``AdminSite`` instance
     from django.conf.urls import patterns, include
     from django.contrib import admin
 
-    admin.autodiscover()
-
     urlpatterns = patterns('',
         (r'^admin/', include(admin.site.urls)),
     )
 
-Above we used ``admin.autodiscover()`` to automatically load the
-:setting:`INSTALLED_APPS` admin.py modules.
-
 In this example, we register the ``AdminSite`` instance
 ``myproject.admin.admin_site`` at the URL ``/myadmin/`` ::
 
@@ -2397,9 +2426,11 @@ In this example, we register the ``AdminSite`` instance
         (r'^myadmin/', include(admin_site.urls)),
     )
 
-There is really no need to use autodiscover when using your own ``AdminSite``
-instance since you will likely be importing all the per-app admin.py modules
-in your ``myproject.admin`` module.
+Note that you don't need autodiscovery of ``admin`` modules when using your
+own ``AdminSite`` instance since you will likely be importing all the per-app
+``admin`` modules in your ``myproject.admin`` module. This means you likely do
+not need ``'django.contrib.admin.app.AdminConfig'`` in your
+:setting:`INSTALLED_APPS` and can just use ``'django.contrib.admin'``.
 
 Multiple admin sites in the same URLconf
 ----------------------------------------

docs/ref/contrib/gis/tutorial.txt

@@ -115,7 +115,7 @@ In addition, modify the :setting:`INSTALLED_APPS` setting to include
 and ``world`` (your newly created application)::
 
     INSTALLED_APPS = (
-        'django.contrib.admin',
+        'django.contrib.admin.apps.AdminConfig',
         'django.contrib.auth',
         'django.contrib.contenttypes',
         'django.contrib.sessions',
@@ -734,8 +734,6 @@ Next, edit your ``urls.py`` in the ``geodjango`` application folder as follows::
     from django.conf.urls import patterns, url, include
     from django.contrib.gis import admin
 
-    admin.autodiscover()
-
     urlpatterns = patterns('',
         url(r'^admin/', include(admin.site.urls)),
     )

docs/ref/contrib/index.txt

@@ -14,8 +14,8 @@ those packages have.
 
     For most of these add-ons -- specifically, the add-ons that include either
     models or template tags -- you'll need to add the package name (e.g.,
-    ``'django.contrib.admin'``) to your :setting:`INSTALLED_APPS` setting and
-    re-run ``manage.py migrate``.
+    ``'django.contrib.redirects'``) to your :setting:`INSTALLED_APPS` setting
+    and re-run ``manage.py migrate``.
 
 .. _"batteries included" philosophy: http://docs.python.org/tutorial/stdlib.html#batteries-included
 

docs/releases/1.7.txt

@@ -93,6 +93,13 @@ Improvements thus far include:
   starts, through a deterministic and straightforward process. This should
   make it easier to diagnose import issues such as import loops.
 
+* The admin has an :class:`~django.contrib.admin.apps.AdminConfig` application
+  configuration class. When Django starts, this class takes care of calling
+  :func:`~django.contrib.admin.autodiscover()`. To use it, simply replace
+  ``'django.contrib.admin'`` in :setting:`INSTALLED_APPS` with
+  ``'django.contrib.admin.apps.AdminConfig'`` and remove
+  ``admin.autodiscover()`` from your URLconf.
+
 New method on Field subclasses
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~