Now that the refactorings are complete, it isn't particularly useful any
more, nor very well named. Let's keep the API as simple as possible.
Fixed#21689.
To the best of my understanding, since populate_models() is now called
as soon as Django starts, it cannot be called while a models module is
being imported, and that removes the need for postponing.
(If hell breaks loose we'll revert this commit.)
Refs #21681.
Since it triggers imports, it shouldn't be done lightly.
This commit adds a public API for doing it explicitly, django.setup(),
and does it automatically when using manage.py and wsgi.py.
Thanks Florian for isolating the shortest way to reproduce this issue:
./runtests.py \
django.contrib.auth.tests.test_context_processors.AuthContextProcessorTests.test_perms_attrs \
django.contrib.auth.tests.test_auth_backends.ChangedBackendSettingsTest.test_changed_backend_settings \
django.contrib.auth.tests.test_auth_backends.CustomUserModelBackendAuthenticateTest.test_authenticate \
django.contrib.auth.tests.test_basic.BasicTestCase.test_createsuperuser_management_command
SQLite accepts the relevant standard SQL (although by default it doesn't
enforce the constraint), and the 'traditional' creation backend helper
generate it, so this allows us to:
- Maintain the status quo
- Improve readability of the SQL code generated for that backend.
Also, we will need this for when we fix Refs #14204.
Returning None on errors required unpythonic error checking and was
inconsistent with get_app_config.
get_model was a private API until the previous commit, but given that it
was certainly used in third party software, the change is explained in
the release notes.
Applied the same change to get_registered_model, which is a new private
API introduced during the recent refactoring.
ContentTypes are only created for installed applications, and I could
make a case for not returning a model that isn't installed any more.
The check for stale ContentTypes in update_contenttypes doesn't use
model_class.
ModelSignal actually needs get_registered_model since the lookup happens
at import time. I took this opportunity to perform a small refactoring.