Registration cycle with custom and historized User model and simple-history 2.5.0

[pm13]

Describe the bug
I have custom user model in module which imports simple_history.models (I think it is common to register historical records in models.py with custom user model.) It worked with simple-history 2.4.0.

But there is new call of get_user_model on class level (3726327). It raises exception:

File ".../models.py", line ..., in
import simple_history.models
File ".../simple_history/models.py", line 29, in
User = get_user_model()
File ".../django/contrib/auth/init.py", line 170, in get_user_model
"AUTH_USER_MODEL refers to model '%s' that has not been installed" % settings.AUTH_USER_MODEL
django.core.exceptions.ImproperlyConfigured: AUTH_USER_MODEL refers to model '....User' that has not been installed

Class level User variable is used only once - so it is quite simple to call get_user_model in get_extra_fields method (one line down :)) - it solves problem.

To Reproduce

1. Define custom user model and import simple_history.models in models.py (for historization of users).
2. Set AUTH_USER_MODEL to this model.

Environment:

• Django Simple History Version: 2.5.0
• Django Version: 2.1.2

[rossmechanic]

Thanks for catching the @pm13. I'll try to merge a bugfix ASAP. Can you describe a little more clearly what fixed the issue? I'm looking at #435 now and also looking at https://docs.djangoproject.com/en/1.11/topics/auth/customizing/#referencing-the-user-model. @ThePumpingLemma think we should just revert that commit based on django docs?

[rossmechanic]

Just put up a PR for the fix. Going to have @ThePumpingLemma review and then merge. Should have a release with the fix out by EOD

[pm13]

I modify the patch - it was my solution of the problem. It is not full revert but only move of get_user_model.