Sphinx mock issue with django `get_user_model` in a custom pakage for django

Question

I am creating a custom package for a django project. The package contains two authentication backends. I have modules configured as below,

# Backend 1 module
from django.contrib.auth import get_user_model
from django.contrib.auth.backends import ModelBackend

UserModel = get_user_model()
# ModelBackend = object  # This will fix actual import issue and uses mocked import only

class AuthBackendOne(ModelBackend):
    pass

# Backend 2 module
from django.contrib.auth import get_user_model
from django.contrib.auth.backends import ModelBackend

UserModel = get_user_model()  # here calls actual django method

class AuthBackendTwo(ModelBackend):
    pass

In my sphinx conf.py I haveautodoc_mock_imports = [ "django.conf", "django.contrib.auth" ]

Issue:

The problem is when I generate sphinx-build for docs, in module 2 it is trying to call actual django get_user_model(). It is not considering that was mocked. By trying myself, I found the issue was when I use ModelBackend to base my custom backend class. No issue in importing ModelBackend, but using that breaks the module 2. Just before using ModelBackend, I have re-assigned to object and run sphinx-build with successful.

Findings:

For my test trials I have printed the UserModel and its type in the above two methods, (I didn't call the get_user_model function in this test)

cognito - CustomBackend 1 ldap - CustomBackend 2

• In the normal way (ModelBackend not reassigned to object):

  cognito sources... [ 33%] kala_common.auth.cognito                                                                                                                                                                         
  django.contrib.auth.get_user_model
  <class 'django.contrib.auth.get_user_model'>
  ldaping sources... [ 40%] kala_common.auth.ldap                                                                                                                                                                            
  <function get_user_model at 0x7f386829f1c0>
  <class 'function'>
  

• In the test method (ModelBackend reassigned as object):

  cognito sources... [ 33%] kala_common.auth.cognito                                                                                                                                                                         
  django.contrib.auth.get_user_model
  <class 'django.contrib.auth.get_user_model'>
  ldaping sources... [ 40%] kala_common.auth.ldap                                                                                                                                                                            
  django.contrib.auth.get_user_model
  <class 'django.contrib.auth.get_user_model'>
  

Note type of ldap in both : as function and as class

So, what should I do to fix the issue, I have tried including ModelBackend in autodoc mock as well..

Answer 1

To resolve some django imports during sphinx-doc build for my package, I have made the below changes.

1. mocked django.contrib.auth.__init__ (get_user_model is defined in there)
2. Also to work other django functionality I have setup a minimal django settings.

# doc/source/conf.py  - configuration sphinx documentation

# ... other sphinx doc configuration

# this resolves importing issue of settings from django.conf
autodoc_mock_imports = [
    "django.conf",
    # ... rest of other mock modules
]

# this resolved get_user_model issue
sys.modules["django.contrib.auth.__init__"] = MagicMock()


# django minimal settings config
import django
from django.conf import settings

DJANGO_APPS = [
    "django.contrib.auth",
    "django.contrib.contenttypes",
]
settings.configure(DEBUG=True, INSTALLED_APPS=DJANGO_APPS)
django.setup()

my previous answer did worked at that time, idk how!! But not working now, however this, completely fixes issues with sphinx-doc build now :-)

Answer 2

Using MagicMock on django's backend module I was able to solve the issue;

# conf.py - of sphinx

from unittest.mock import MagicMock

sys.modules["django.contrib.auth.backends"] = MagicMock()

If anyone have any better solution, please do suggest me.