Python Django - "AUTH_USER_MODEL refers to model '%s' that has not been installed" % settings.AUTH_USER_MODEL

Question

If there is any bug in my code (code within a model that is used within a view which uses LoginRequiredMixin ) e.g. A bug like:

if (True:    # <-- example bug to show how bugs like this are hidden

Then I get the following error:

"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 'auth.User' that has not been installed

This makes it really hard to debug the code. I have figured out if I remove this line from my views.py:

from django.contrib.auth.mixins import LoginRequiredMixin

Even if I remove all instances where LoginRequiredMixin is used, just by importing it, it hides the true bug and generates the above auth error.

I have read: AUTH_USER_MODEL refers to model '%s' that has not been installed" % settings.AUTH_USER_MODEL

My research shows most of the time this is due to "django.contrib.auth'" missing from INSTALLED_APPS, which you can see I have (settings.py snippet, Django 2.2):

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth', # <-- Important for this topic!
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'myapp.apps.CommonConfig',
]

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

I tried adding this to above the mixim import but neither helped:

from django.contrib import auth
from django.contrib.auth.models import User

This part of the full traceback agrees with the above:

Traceback (most recent call last):
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\apps\registry.py", line 155, in get_app_config
    return self.app_configs[app_label]
KeyError: 'auth'

Here is the traceback if I call makemigrations (This is what I expect):

    C:\code\myproject\src>pipenv run python manage.py makemigrations
Traceback (most recent call last):
  File "manage.py", line 15, in <module>
    execute_from_command_line(sys.argv)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\core\management\__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\core\management\__init__.py", line 357, in execute
    django.setup()
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\apps\registry.py", line 114, in populate
    app_config.import_models()
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\apps\config.py", line 211, in import_models
    self.models_module = import_module(models_module_name)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "C:\code\myproject\src\myapp\models.py", line 14, in <module>
    from .sql import myapp_entry_clean, myapp_entry_grouping
  File "C:\code\myproject\src\myapp\sql.py", line 68
    if (True:
            ^
SyntaxError: invalid syntax

C:\code\myproject\src>

Here is the traceback with runserver:

    C:\code\myproject\src>pipenv run python manage.py runserver
Watching for file changes with StatReloader
Exception in thread Thread-1:
Traceback (most recent call last):
  File "C:\Users\User\AppData\Local\Programs\Python\Python36\Lib\threading.py", line 916, in _bootstrap_inner
    self.run()
  File "C:\Users\User\AppData\Local\Programs\Python\Python36\Lib\threading.py", line 864, in run
    self._target(*self._args, **self._kwargs)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\utils\autoreload.py", line 54, in wrapper
    fn(*args, **kwargs)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\core\management\commands\runserver.py", line 109, in inner_run
    autoreload.raise_last_exception()
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\utils\autoreload.py", line 77, in raise_last_exception
    raise _exception[0](_exception[1]).with_traceback(_exception[2])
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\utils\autoreload.py", line 54, in wrapper
    fn(*args, **kwargs)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\apps\registry.py", line 114, in populate
    app_config.import_models()
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\apps\config.py", line 211, in import_models
    self.models_module = import_module(models_module_name)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "C:\code\myproject\src\myapp\models.py", line 14, in <module>
    from .sql import myapp_entry_clean, myapp_entry_grouping
  File "<string>", line None
SyntaxError: invalid syntax (sql.py, line 68)

Traceback (most recent call last):
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\apps\registry.py", line 155, in get_app_config
    return self.app_configs[app_label]
KeyError: 'auth'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\contrib\auth\__init__.py", line 165, in get_user_model
    return django_apps.get_model(settings.AUTH_USER_MODEL, require_ready=False)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\apps\registry.py", line 205, in get_model
    app_config = self.get_app_config(app_label)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\apps\registry.py", line 162, in get_app_config
    raise LookupError(message)
LookupError: No installed app with label 'auth'.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "manage.py", line 15, in <module>
    execute_from_command_line(sys.argv)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\core\management\__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\core\management\__init__.py", line 375, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\core\management\base.py", line 323, in run_from_argv
    self.execute(*args, **cmd_options)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\core\management\commands\runserver.py", line 60, in execute
    super().execute(*args, **options)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\core\management\base.py", line 364, in execute
    output = self.handle(*args, **options)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\core\management\commands\runserver.py", line 95, in handle
    self.run(**options)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\core\management\commands\runserver.py", line 102, in run
    autoreload.run_with_reloader(self.inner_run, **options)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\utils\autoreload.py", line 579, in run_with_reloader
    start_django(reloader, main_func, *args, **kwargs)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\utils\autoreload.py", line 564, in start_django
    reloader.run(django_main_thread)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\utils\autoreload.py", line 272, in run
    get_resolver().urlconf_module
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\utils\functional.py", line 80, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\urls\resolvers.py", line 564, in urlconf_module
    return import_module(self.urlconf_name)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "C:\code\myproject\src\linkcube\urls.py", line 20, in <module>
    path('', include('common.urls')),
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\urls\conf.py", line 34, in include
    urlconf_module = import_module(urlconf_module)
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "C:\code\myproject\src\common\urls.py", line 5, in <module>
    from . import views
  File "C:\code\myproject\src\common\views.py", line 9, in <module>
    from django.contrib.auth.mixins import LoginRequiredMixin
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\contrib\auth\mixins.py", line 3, in <module>
    from django.contrib.auth.views import redirect_to_login
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\contrib\auth\views.py", line 10, in <module>
    from django.contrib.auth.forms import (
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\django\contrib\auth\forms.py", line 20, in <module>
    UserModel = get_user_model()
  File "C:\Users\User\.virtualenvs\myproject-wc-xNQPL\lib\site-packages\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 'auth.User' that has not been installed

C:\code\myproject\src>

How do I make it so that the auth error is not falsely raised?

Answer 1

So the issue here is a python syntax error, but (maybe) since you are running Django framework, Django suppresses that and throws the missing model error.

Since python is interpreted language it threw an error for SyntaxError and since there was syntax error Django did not find auth model reference.

That's why you see both the errors there, python's SyntaxError and Django's ImproperlyConfigured error.

Django is kind enough to let you know that the Django's error is caused by the python's syntax error.

Answer 2

If you are getting that error message, I belive you are using a custom user model. You may want to try to use AUTH_USER_MODEL on your relationships instead of the direct model User or the get_user_model method. This pretty much cleared the bug for me. I got the solution from https://learndjango.com/tutorials/django-best-practices-referencing-user-model

The way to use AUTH_USER_MODEL is by first importing it from the settings usingfrom django.conf import settings and on the field that requires the relationship, you use it as, for example seller = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)