#19472: AttributeError: Problem installing auth.user fixtures with swapped user
model
-------------------------------+------------------------
Reporter: gcc | Owner: nobody
Type: Uncategorized | Status: new
Component: contrib.auth | Version: 1.5-beta-1
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------+------------------------
If a project swaps out a user model, then fixtures in apps that refer to
auth.user don't work, which breaks their tests. This makes it impossible
to write reusable apps whose tests still work when the user model is
swapped out.
I've created a [https://github.com/qris/django-swapout-user-model-breaks-
app-tests test case] which fails like this:
{{{
chris@lap-x201:~/user_swapout_test/project$ ../ve/bin/python manage.py
test app_with_user_fixtures
Creating test database for alias 'default'...
E
======================================================================
ERROR: test_basic_addition (app_with_user_fixtures.tests.SimpleTest)
----------------------------------------------------------------------
Traceback (most recent call last):
File
"/home/installuser/Dropbox/projects/ischool/user_swapout_test/ve/local/lib/python2.7
/site-packages/django/test/testcases.py", line 256, in __call__
self._pre_setup()
File
"/home/installuser/Dropbox/projects/ischool/user_swapout_test/ve/local/lib/python2.7
/site-packages/django/test/testcases.py", line 450, in _pre_setup
self._fixture_setup()
File
"/home/installuser/Dropbox/projects/ischool/user_swapout_test/ve/local/lib/python2.7
/site-packages/django/test/testcases.py", line 828, in _fixture_setup
'skip_validation': True,
File
"/home/installuser/Dropbox/projects/ischool/user_swapout_test/ve/local/lib/python2.7
/site-packages/django/core/management/__init__.py", line 161, in
call_command
return klass.execute(*args, **defaults)
File
"/home/installuser/Dropbox/projects/ischool/user_swapout_test/ve/local/lib/python2.7
/site-packages/django/core/management/base.py", line 252, in execute
output = self.handle(*args, **options)
File
"/home/installuser/Dropbox/projects/ischool/user_swapout_test/ve/local/lib/python2.7
/site-packages/django/core/management/commands/loaddata.py", line 111, in
handle
self.load_label(fixture_label, app_fixtures)
File
"/home/installuser/Dropbox/projects/ischool/user_swapout_test/ve/local/lib/python2.7
/site-packages/django/core/management/commands/loaddata.py", line 194, in
load_label
formats)
File
"/home/installuser/Dropbox/projects/ischool/user_swapout_test/ve/local/lib/python2.7
/site-packages/django/core/management/commands/loaddata.py", line 246, in
process_dir
obj.save(using=self.using)
File
"/home/installuser/Dropbox/projects/ischool/user_swapout_test/ve/local/lib/python2.7
/site-packages/django/core/serializers/base.py", line 167, in save
models.Model.save_base(self.object, using=using, raw=True)
File
"/home/installuser/Dropbox/projects/ischool/user_swapout_test/ve/local/lib/python2.7
/site-packages/django/db/models/base.py", line 604, in save_base
manager.using(using).filter(pk=pk_val).exists())):
AttributeError: Problem installing fixture
'/home/installuser/Dropbox/projects/ischool/user_swapout_test/project/app_with_user_fixtures/fixtures/users.json':
'NoneType' object has no attribute 'using'
----------------------------------------------------------------------
Ran 0 tests in 0.006s
FAILED (errors=1)
Destroying test database for alias 'default'...
}}}
If I add some instrumentation to find out why the manager is None:
{{{
manager = cls._base_manager
if manager is None:
raise ValueError(("%s must have a valid Manager to create " +
"instances") % cls)
}}}
Then I can see that it's `django.contrib.auth.models.User` that has no
manager:
{{{
ValueError: Problem installing fixture
'/home/installuser/Dropbox/projects/ischool/user_swapout_test/project/app_with_user_fixtures/fixtures/users.json':
<class 'django.contrib.auth.models.User'> must have a valid Manager to
create instances
}}}
I wonder if we need a special case for UserModel in fixtures. Of course if
you swap out the user model for one that doesn't contain the necessary
fields, then the fixture cannot be loaded, and the test should fail in
that case. But when the fields are present, we should be able to load the
fixtures.
Perhaps we could special case the content_type `auth.user` and any
(future) swappable model class content types, to refer to the swapped-in
model instead of the swapped-out one, for backwards compatibility?
--
Ticket URL: <https://code.djangoproject.com/ticket/19472>
Django <https://code.djangoproject.com/>
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