Deprecated importing a model before loading its application.

Refs #21719, #21680.

3 files changed, 25 insertions, 3 deletions

diff --git a/docs/internals/deprecation.txt b/docs/internals/deprecation.txt
index 1b8b45a520..514561e1ff 100644
--- a/docs/internals/deprecation.txt
+++ b/docs/internals/deprecation.txt
@@ -170,6 +170,12 @@ these changes.
 * ``allow_syncdb`` on database routers will no longer automatically become
   ``allow_migrate``.
 
+* All models will need to be defined inside an installed application or
+  declare an explicit :attr:`~django.db.models.Options.app_label`.
+  Furthermore, it won't be possible to import them before their application
+  is loaded. In particular, it won't be possible to import models inside
+  the root package of their application.
+
 * If models are organized in a package, Django will no longer look for
   :ref:`initial SQL data<initial-sql>` in ``myapp/models/sql/``. Move your
   custom SQL files to ``myapp/sql/``.
diff --git a/docs/ref/applications.txt b/docs/ref/applications.txt
index a44062808e..e496f24487 100644
--- a/docs/ref/applications.txt
+++ b/docs/ref/applications.txt
@@ -181,6 +181,13 @@ Methods
     as registering signals. It is called as soon as the registry is fully
     populated.
 
+    You cannot import models in modules that define application configuration
+    classes, but you can use :meth:`get_model` to access a model class by
+    name, like this::
+
+        def ready(self):
+            MyModel = self.get_model('MyModel')
+
 Application registry
 ====================
 
diff --git a/docs/releases/1.7.txt b/docs/releases/1.7.txt
index a8becf1bab..9fcad38931 100644
--- a/docs/releases/1.7.txt
+++ b/docs/releases/1.7.txt
@@ -677,9 +677,18 @@ directory and a subdirectory on :envvar:`PYTHONPATH`. Refer to the section on
 the new project layout in the :doc:`1.4 release notes </releases/1.4>` for
 migration instructions.
 
-You should make sure that your project doesn't import models from applications
-that aren't in :setting:`INSTALLED_APPS`. Relations involving such models may
-not be created properly. Future versions of Django may forbid this entirely.
+You should make sure that:
+
+* All models are defined in applications that are listed in
+  :setting:`INSTALLED_APPS` or have an explicit
+  :attr:`~django.db.models.Options.app_label`.
+
+* Models aren't imported as a side-effect of loading their application.
+  Specifically, you shouldn't import models in the root module of an
+  application nor in the module that define its configuration class.
+
+Django will enforce these requirements as of version 1.9, after a deprecation
+period.
 
 Subclassing AppCommand
 ^^^^^^^^^^^^^^^^^^^^^^