So, this is an extension of what I asked last week (Why do I need to import a class within this class, instead of at the top of the file?) but after extensive debugging, I feel like it might warrant a new question.
I have a number of modules, all with imports. I suspect there may be a circular import but I haven't been able to find it.
Here's the weird thing:
In one models.py file, I have:
from django.db import models
from django.core.exceptions import ObjectDoesNotExist
from heythere.models import Notification as HeyThere
from heythere.models import NotificationManager as HeyThereManager
from django.contrib.auth.models import User
then some model definitions, including one with a method:
def to_user(self):
try:
return User.objects.get(username=str(self.username))
except ObjectDoesNotExist:
return None
and a little further down:
from ownership.apps.Assets.models import Item
When it's like this, I get AttributeError: 'NoneType' object has no attribute 'objects' (referring to User). So it's set to None, somehow, as opposed to raising a global name XXX is not defined.
BUT THEN, I tried accessing the User right after the import:
me = User.objects.get(username='xxxx')
print me
It printed correctly upon running runserver, so I know it can access User there, but then gave me the error message ImportError: cannot import name Item. How did simply accessing the model cause an import error? (FWIW, Item does have a number of FK relations to User)
What gives?
Traceback when User.objects.get() is included:
File "/Users/xxxxx/.virtualenvs/ownership/lib/python2.7/site-packages/django/utils/autoreload.py", line 93, in wrapper
fn(*args, **kwargs)
File "/Users/xxxxx/.virtualenvs/ownership/lib/python2.7/site-packages/django/core/management/commands/runserver.py", line 101, in inner_run
self.validate(display_num_errors=True)
File "/Users/xxxxx/.virtualenvs/ownership/lib/python2.7/site-packages/django/core/management/base.py", line 310, in validate
num_errors = get_validation_errors(s, app)
File "/Users/xxxxx/.virtualenvs/ownership/lib/python2.7/site-packages/django/core/management/validation.py", line 34, in get_validation_errors
for (app_name, error) in get_app_errors().items():
File "/Users/xxxxx/.virtualenvs/ownership/lib/python2.7/site-packages/django/db/models/loading.py", line 196, in get_app_errors
self._populate()
File "/Users/xxxxx/.virtualenvs/ownership/lib/python2.7/site-packages/django/db/models/loading.py", line 78, in _populate
self.load_app(app_name)
File "/Users/xxxxx/.virtualenvs/ownership/lib/python2.7/site-packages/django/db/models/loading.py", line 99, in load_app
models = import_module('%s.models' % app_name)
File "/Users/xxxxx/.virtualenvs/ownership/lib/python2.7/site-packages/django/utils/importlib.py", line 40, in import_module
__import__(name)
File "/Users/xxxxx/code/ownership/ownership/apps/Assets/models.py", line 12, in <module>
import permissions
File "/Users/xxxxx/code/ownership/ownership/apps/Assets/permissions.py", line 4, in <module>
from ownership.apps.Shared.models import Person
File "/Users/xxxxx/code/ownership/ownership/apps/Shared/models.py", line 87, in <module>
from ownership.apps.Assets.models import Item
ImportError: cannot import name Item
And without (how the code should work):
Environment:
Request Method: POST
Request URL: http://localhost:8000/application/new
Django Version: 1.6.1
Python Version: 2.7.2
Installed Applications:
('suit',
'south',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.redirects',
'django.contrib.messages',
'django.contrib.staticfiles',
'django.contrib.admin',
'rest_framework',
'ldap_sync',
'crispy_forms',
'ownership.apps.Catalog',
'ownership.apps.Assets',
'ownership.apps.Shared',
'ownership.libs.display',
'django_tables2',
'haystack',
'autocomplete_light',
'reversion',
'heythere',
'polymorphic',
'django_extensions',
'debug_toolbar')
Installed Middleware:
('django.middleware.common.CommonMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.contrib.redirects.middleware.RedirectFallbackMiddleware',
'django.middleware.transaction.TransactionMiddleware',
'reversion.middleware.RevisionMiddleware',
'ownership.libs.shibboleth.CustomHeaderMiddleware',
'debug_toolbar.middleware.DebugToolbarMiddleware')
Traceback:
File "/Users/xxxxx/.virtualenvs/ownership/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
114. response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/Users/xxxxx/code/ownership/ownership/apps/Assets/crud_views.py" in connect_create_view
48. return subview.as_view()(request, model_name=model_name)
File "/Users/xxxxx/.virtualenvs/ownership/lib/python2.7/site-packages/django/views/generic/base.py" in view
69. return self.dispatch(request, *args, **kwargs)
File "/Users/xxxxx/.virtualenvs/ownership/lib/python2.7/site-packages/django/views/generic/base.py" in dispatch
87. return handler(request, *args, **kwargs)
File "/Users/xxxxx/code/ownership/ownership/apps/Assets/crud_views.py" in post
280. create_new_asset_notification(request, new_item)
File "/Users/xxxxx/code/ownership/ownership/apps/Shared/views.py" in create_new_asset_notification
123. send_email(request, subject, body, owner.to_user().email, )
File "/Users/xxxxx/code/ownership/ownership/apps/Shared/models.py" in to_user
52. return User.objects.get(username=str(self.username))
Exception Type: AttributeError at /application/new
Exception Value: 'NoneType' object has no attribute 'objects'
