Move admin.autodiscover() to AppConfig.setup()

[Aymeric Augustin]

It doesn't belong to urls.py!

This probably requires shipping an apps.py with an AppConfig in the default project template and adding lots of documentation, including in the tutorial.

[Aymeric Augustin]

In fact, we don't have a good API for project-level startup code. Many projects have a "project app" for projectwide templates, staticfiles, etc. but the tutorial doesn't. This requires a bit more thought.

[Aymeric Augustin]

It may be more appropriate to put it in the admin AppConfig (once there's one, #21675) and to document how do disable it (via subclassing).

[Aymeric Augustin]

Summarizing a discussion with Marc on IRC:

• ​https://gist.github.com/mjtamlyn/8209667
• explain in the release notes to use 'django.contrib.admin.app.AdminConfig' instead of 'django.contrib.admin' in INSTALLED_APPS and remove admin.autodiscover() from urls.py.

[Marc Tamlyn]

PR submitted. There are at least three things to consider which are in the PR - including naming of the file, default project and testing.

​https://github.com/django/django/pull/2136

[Bas Peschier]

I would change the default project to use the AdminConfig. My guess is most people use the autodiscover method. People implementing their own AdminSite can read the documentation about it.

[Claude Paroz]

+1 to change the default project.
I'd keep the app.py name. apps.py would suggest several applications.
I'd also add verbose_name = _("Django administration").

[Marc Tamlyn]

The last point about the verbose_name is tracked in #21675 as it covers all contrib apps.

[Aymeric Augustin]

Yes, we must change the default project template. We should also copy-paste the usual warnings in the tutorial for people who don't check properly what version they're using.

We've decided to always use apps.py. Let's stick with that.

[Aymeric Augustin]

It's impossible to make this change in the test suite because it relies on the admin autodiscovery not being run.

The bug8245 test app contains an invalid admin module that breaks autodiscovery.

[Aymeric Augustin]

New PR: ​https://github.com/django/django/pull/2182

I think it's good to go but I would appreciate a proof-read. It's mostly a documentation patch.

[Claude Paroz]

I've only read the patch, but it looks good to me (except reported typos).

[Aymeric Augustin <aymeric.augustin@…>]

In 10e0cfc0e4e77b85e8261c908baf1c4814ded3f8:

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

Thanks Marc Tamlyn for the initial version of the patch.