Don't allow admin.site.register([]) or admin.site.unregister([])

[anabelensc]

Hello,

I think if you do that :
admin.site.register([]) or admin.site.unregister([]) the function register and unregister should complain.
I attach a pacth to try to fix this.

Thanks.

[Aymeric Augustin]

I'm not convinced that a good idea.

Some users may be passing a possibly-empty-list to admin.site.register in order to avoid having to special-case the empty list.

[Tim Graham]

Maybe we can remove the check added in #25688 too. Are you able to submit your patch as a pull request?

[anabelensc]

Yes, I can
thank you

[Tim Graham]

Aymeric, could you give an example of such a pattern? I can't come up with a situation where an empty list would be inadvertently passed either, so I don't care much either way.

[Simon Charette]

Replying to timgraham:

Aymeric, could you give an example of such a pattern? I can't come up with a situation where an empty list would be inadvertently passed either, so I don't care much either way.

If the list consist of models that can be present or not in a third-party application setting with optional dependencies.

models = []
for app_label in ['optional1', 'optional2']:
    try:
        app = apps.get_app_config(app_label)
    except LookupError:
        continue
    models.extend(app.get_models())

I've not used apps this way personally but I've seen a couple of third party applications in the wild that rely on ImportError to register or not optional dependency models to the admin.

Even if this pattern is not common I agree with Aymeric that it's not a good idea. Plus this is backward incompatible and would require a deprecation which is a lot of trouble for a check that could raise false positives.