django.setup() should be idempotent

[pascal chambon]

I've been bitten numerous times by the impredictable behaviour of django
when django.setup() was called numerous times.

In the old days I had exceptions, now it's mainly subtle breakages of
logging configuration.

I couldn't find, in the issue tracker or the dev mailing list statements
about this subject, others than request from other users encountering the
problem.

For example this ticket concerned script+importable modules :
https://code.djangoproject.com/ticket/26152

The latest case in date for me is pytest-django having troubles with
these multiple setup() calls : ​https://github.com/pytest-dev/pytest-
django/issues/531 , due to multiple fixtures attempting this auto-setup.

Would it be OK to make django.setup() idempotent, or even expose a
"is_ready" flag for easier introspection ?

[Tim Graham]

I believe this is addressed in Django 2.0 by #27176. If not, please reopen with a minimal project that reproduces the problem you're encountering.

[Tim Graham]

Thanks. Can you explain the use case for calling django.setup() multiple times?