Multiple django.setup() calls break other plugins

[pakal]

In pytest-django hooks, _setup_django() is called multiple times, in conftest setup and as a a trylast, and it leads to multiple resets of logging config (driven by django LOGGING setting).

Inbetween these calls, other plugins like pytest-capturelog try to setup their own logging handlers, but these get reset. I've monkey patched like below, but I guess _setup_django() could use a flag to prevent its multiple execution.

def pytest_configure():
    # we have to prevent bug where pytest calls django.setup() multiple
    # times, breaking the logging conf (and pytest-capturelog plugin)
    import django.apps
    if django.apps.apps.ready:
        django.setup = lambda: None

[blueyed]

Thanks for the report.

It would be nice to have a failing test case for pytest-django itself as a first step.

[pakal]

Here is a testcase to show the problem : #538

I tested it against python2.7 and Django==1.11.6, sorry I couldn't use the whole test suite or tox locally since there are lots of breakages on windows (something to do with file locking on DB removal).

Basically django.setup() should be idempotent, but in the meantime a workaround can be added here (I talk with django devs about this evolution).

[pakal]

For reference, the ticket on Django side : https://code.djangoproject.com/ticket/28752#ticket

[blueyed]

@pakal

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

There is django.conf.settings.configured for this I think?!

[pakal]

Is it the same thing ?

It looks like "settings.configured" is to say that a source of settings has been specified, not that django.setup() has been called, but it's fuzzy for me : https://docs.djangoproject.com/en/1.11/topics/settings/#either-configure-or-django-settings-module-is-required

[blueyed]

I am not sure, but it came to my mind - IIRC pytest-django has checks for this at least.. haven't looked at the code, nor do I remember it apparently good enough, sorry.

/cc @pelme

[blueyed]

Please test/review #629.