TypeError: check() got an unexpected keyword argument 'databases'

[Stian Jensen]

When updating from django 3.0.10 to 3.1.0 (also 3.1.1), I get a new error when running management commands that involve running system checks.
The whole stack trace involves only django code (no other third-party packages), so I assume this cannot be related to other packages I have installed.

I saw something in the release notes about a new --database flag to the check command, but I cannot piece together if it has anything to do with this error (Running manage.py check with '--database default' does not remove the crash, for instance).

.venv/bin/python manage.py check
Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "app/.venv/lib/python3.8/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line
    utility.execute()
  File "app/.venv/lib/python3.8/site-packages/django/core/management/__init__.py", line 395, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "app/.venv/lib/python3.8/site-packages/django/core/management/base.py", line 330, in run_from_argv
    self.execute(*args, **cmd_options)
  File "app/.venv/lib/python3.8/site-packages/django/core/management/base.py", line 371, in execute
    output = self.handle(*args, **options)
  File "app/.venv/lib/python3.8/site-packages/django/core/management/commands/check.py", line 63, in handle
    self.check(
  File "app/.venv/lib/python3.8/site-packages/django/core/management/base.py", line 392, in check
    all_issues = checks.run_checks(
  File "app/.venv/lib/python3.8/site-packages/django/core/checks/registry.py", line 70, in run_checks
    new_errors = check(app_configs=app_configs, databases=databases)
  File "app/.venv/lib/python3.8/site-packages/django/core/checks/model_checks.py", line 34, in check_all_models
    errors.extend(model.check(**kwargs))
  File "app/.venv/lib/python3.8/site-packages/django/db/models/base.py", line 1264, in check
    *cls._check_fields(**kwargs),
  File "app/.venv/lib/python3.8/site-packages/django/db/models/base.py", line 1343, in _check_fields
    errors.extend(field.check(**kwargs))
TypeError: check() got an unexpected keyword argument 'databases'

(I stripped out some of the absolute paths to file names that should be irrelevant from the traceback)

[Mariusz Felisiak]

Thanks for this ticket however I cannot reproduce this issue. Can you provide a small project?

[Stian Jensen]

Hi, after trying to make a reproduce I finally tracked down the issue in our codebase. We have a custom model field where we've overridden the check method to do some extra validation of the field config. That method wasn't setup to take in **kwargs. It seems like something has changed in django 3.1 that now sends databases as a kwarg, so just changing our method signature to check(self, **kwargs): solved the problem.

Thanks, and sorry for the incorrect bug report!

[Mariusz Felisiak]

Thanks for checking.