Adding custom QuerySet to UserModel causes makemigrations exception

Question

I would like to create a custom queryset for my User model. However, I cannot simply use objects = UserQuerySet.as_manager() since the standard Django User model already has a custom UserManager.

My code is simply :

class UserQuerySet(MyBaseQuerySet):
    def opted_out_method(self):
        return

class User(AbstractUser):
    objects = UserManager.from_queryset(UserQuerySet)()
    # etc... 

This code works, except when I do this:

$manage.py makemigrations --dry-run
  File "./manage.py", line 49, in <module>
    execute_from_command_line(sys.argv)
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/core/management/__init__.py", line 375, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/core/management/base.py", line 323, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/core/management/base.py", line 364, in execute
    output = self.handle(*args, **options)
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/core/management/base.py", line 83, in wrapped
    res = handle_func(*args, **kwargs)
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/core/management/commands/makemigrations.py", line 164, in handle
    changes = autodetector.changes(
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/db/migrations/autodetector.py", line 43, in changes
    changes = self._detect_changes(convert_apps, graph)
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/db/migrations/autodetector.py", line 129, in _detect_changes
    self.new_apps = self.to_state.apps
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/utils/functional.py", line 80, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/db/migrations/state.py", line 210, in apps
    return StateApps(self.real_apps, self.models)
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/db/migrations/state.py", line 273, in __init__
    self.render_multiple([*models.values(), *self.real_models])
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/db/migrations/state.py", line 308, in render_multiple
    model.render(self)
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/db/migrations/state.py", line 577, in render
    body.update(self.construct_managers())
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/db/migrations/state.py", line 536, in construct_managers
    as_manager, manager_path, qs_path, args, kwargs = manager.deconstruct()
  File "/home/user/.cache/pypoetry/virtualenvs/django-app-4WxKU_E8-py3.8/lib/python3.8/site-packages/django/db/models/manager.py", line 61, in deconstruct
    raise ValueError(

The exception raised is "Could not find manager. Please note that you need to inherit from managers you dynamically generated with 'from_queryset()", which is what I'm doing.

Has anyone run into this before?

I'm currently using Django 2.2, not sure if this is fixed in 3+.

Answer 1

The solution is to create a custom manager that derives from UserManager.

from django.contrib.auth.models import UserManager

class MyCustomUserManager(UserManager):
    def bob_filter(self):
        return super().get_queryset().filter(first_name__icontains="bob")
    # etc...

class User(AbstractUser):
    objects = managers.CustomUserManager()
    # etc...