ImproperlyConfigured exceptions should be raised immediately.

[Alasdair Nicol]

When an older version of sqlite is installed, the final line of the traceback in runserver is unrelated.

    raise LookupError(message)
LookupError: No installed app with label 'admin'.

If you look further up the traceback, you can see what the problem is, but this can be tricky for newer users.

    raise ImproperlyConfigured('SQLite 3.8.3 or later is required (found %s).' % Database.sqlite_version)
django.core.exceptions.ImproperlyConfigured: SQLite 3.8.3 or later is required (found 3.7.17).

I think that if we made the error message clearer it would be helpful for new users. Perhaps we could do this by checking the sqlite version in a system check, or maybe there's a better approach.

Related Stack Overflow question: ​https://stackoverflow.com/questions/55512244/no-installed-app-with-label-admin-in-empty-django-2-2-project/

See ​django/apps/registry.py.

[Mariusz Felisiak]

This behavior has been changed somewhere in the Django 2.2. I agree that it is a bug but probably not crucial. It affects all ImproperlyConfigured's exceptions, e.g.

• django.core.exceptions.ImproperlyConfigured: Error loading cx_Oracle module: No module named 'cx_Oracle',
• django.core.exceptions.ImproperlyConfigured: SQLite 3.8.3 or later is required (found 3.7.X)., etc.

[Alasdair Nicol]

I ran git bisect and I believe the behaviour changed in #27685 when the autoloader changed.

Only runserver shows the LookupError last - manage.py check, manage.py migrate and so on all show django.core.exceptions.ImproperlyConfigured.