Django 1.7 upgrade error: AppRegistryNotReady: App

Question

I am trying to upgrade a project from Django 1.6 to 1.7. I get the following error:

[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] mod_wsgi (pid=14523): Exception occurred processing WSGI script '/home/users1/k/kisvadim/domains/mathtasks.org/django.wsgi'.
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] Traceback (most recent call last): 
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/core/handlers/wsgi.py", line 187, in __call__
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] response = self.get_response(request)
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/core/handlers/base.py", line 199, in get_response
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/core/handlers/base.py", line 239, in handle_uncaught_exception
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] if resolver.urlconf_module is None:
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/core/urlresolvers.py", line 361, in urlconf_module
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] self._urlconf_module = import_module(self.urlconf_name)
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] __import__(name)
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/django/mathtasks/mathtasks/urls.py", line 11, in <module>
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] admin.autodiscover()
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/contrib/admin/__init__.py", line 23, in autodiscover
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] autodiscover_modules('admin', register_to=site)
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/utils/module_loading.py", line 67, in autodiscover_modules
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] for app_config in apps.get_app_configs():
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/apps/registry.py", line 137, in get_app_configs
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] self.check_apps_ready()
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/apps/registry.py", line 124, in check_apps_ready
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] raise AppRegistryNotReady("Apps aren't loaded yet.")
[Thu Oct 09 14:16:41 2014] [error] [client 95.79.172.156] AppRegistryNotReady: Apps aren't loaded yet.

django.wsgi:

import os, sys
import django
virtual_env = os.path.expanduser('~/virtualenv/PythonEnv')
activate_this = os.path.join(virtual_env, 'bin/activate_this.py')
execfile(activate_this, dict(__file__=activate_this))
sys.path.insert(0, os.path.join(os.path.expanduser('~'), 'django/mathtasks'))
os.environ['DJANGO_SETTINGS_MODULE'] = 'mathtasks.settings'
django.setup()
import django.core.handlers.wsgi
application = django.core.handlers.wsgi.WSGIHandler()

Any ideas what might be causing the error and how to fix it?

UPDATE1:

I replaced:

from django.contrib.auth.models import User

to:

from django.conf import settings
User = settings.AUTH_USER_MODEL

And I get the following error:

[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] mod_wsgi (pid=17128): Exception occurred processing WSGI script '/home/users1/k/kisvadim/domains/mathtasks.org/django.wsgi'. 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] Traceback (most recent call last): 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/core/handlers/wsgi.py", line 187, in __call__ 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] response = self.get_response(request) 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/core/handlers/base.py", line 199, in get_response 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] response = self.handle_uncaught_exception(request, resolver, sys.exc_info()) 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/core/handlers/base.py", line 239, in handle_uncaught_exception 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] if resolver.urlconf_module is None: 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/core/urlresolvers.py", line 361, in urlconf_module 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] self._urlconf_module = import_module(self.urlconf_name) 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] __import__(name) 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/django/mathtasks/mathtasks/urls.py", line 6, in <module> 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] from utils.views import SniptRegistrationView 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/django/mathtasks/utils/views.py", line 1, in <module> 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] from registration.backends.default.views import RegistrationView 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/django/mathtasks/registration/backends/default/views.py", line 7, in <module> 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] from registration.views import ActivationView as BaseActivationView 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/django/mathtasks/registration/views.py", line 11, in <module> 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] from registration.forms import RegistrationForm 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/django/mathtasks/registration/forms.py", line 159, in <module> 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] class UserProfileForm(forms.ModelForm): 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/forms/models.py", line 284, in __new__ 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] opts.help_texts, opts.error_messages) 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/forms/models.py", line 184, in fields_for_model 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] opts = model._meta 
[Thu Oct 09 15:06:15 2014] [error] [client 95.79.172.156] AttributeError: 'str' object has no attribute '_meta'

UPDATE 2:

I replaced:

from django.contrib.auth.models import User

to:

from django.contrib.auth import get_user_model
User = get_user_model()

and:

models.ForeignKey(settings.AUTH_USER_MODEL)

And I get the following error:

[Thu Oct 09 16:10:52 2014] [error] No handlers could be found for logger "django.request" 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] mod_wsgi (pid=31421): Exception occurred processing WSGI script '/home/users1/k/kisvadim/domains/mathtasks.org/django.wsgi'. 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] Traceback (most recent call last): 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/core/handlers/wsgi.py", line 187, in __call__ 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] response = self.get_response(request) 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/core/handlers/base.py", line 199, in get_response 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] response = self.handle_uncaught_exception(request, resolver, sys.exc_info()) 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/core/handlers/base.py", line 239, in handle_uncaught_exception 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] if resolver.urlconf_module is None: 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/core/urlresolvers.py", line 361, in urlconf_module 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] self._urlconf_module = import_module(self.urlconf_name) 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] __import__(name) 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/django/mathtasks/mathtasks/urls.py", line 6, in <module> 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] from utils.views import SniptRegistrationView 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/django/mathtasks/utils/views.py", line 1, in <module> 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] from registration.backends.default.views import RegistrationView 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/django/mathtasks/registration/backends/default/views.py", line 6, in <module> 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] from registration.models import RegistrationProfile 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/django/mathtasks/registration/models.py", line 9, in <module> 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] User = get_user_model() 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/contrib/auth/__init__.py", line 136, in get_user_model 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] return django_apps.get_model(settings.AUTH_USER_MODEL) 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/apps/registry.py", line 199, in get_model 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] self.check_models_ready() 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] File "/home/users1/k/kisvadim/virtualenv/PythonEnv/lib/python2.7/site-packages/django/apps/registry.py", line 131, in check_models_ready 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] raise AppRegistryNotReady("Models aren't loaded yet.") 
[Thu Oct 09 16:10:52 2014] [error] [client 95.79.172.156] AppRegistryNotReady: Models aren't loaded yet.

Answer 1

It could be any reason. In my case, I updated my python version outside of my virtual environment, but my virtualenv was still the old version, that makes the error. I deleted the env and build it again using the newer version, and it worked.