id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
34565	Exception will be raised when settings.PASSWORD_HASHERS changes and the check_password() method is called in an asynchronous context.	Dingning	nobody	"When `settings.PASSWORD_HASHERS` is changed and `user.check_password()` is called in an async context, a `SynchronousOnlyOperation` exception may occur.

The reason is that the check_password function will call the synchronous setter function to update the password field of the user table when the `settings.PASSWORD_HASHERS` is changed.


== To reproduce the process:
1. Start Django and create a user. Suppose the user's password is 123456.
2. Close the server, modify `settings.PASSWORD_HASHERS`, for example, exchange the order of the first two Hashers. You can refer to `django.conf.global_settings.PASSWORD_HASHERS`.
3. Start the server and call `user.check_password('123456')` in the asynchronous view.
4. `SynchronousOnlyOperation` is raiesd.


== Reference Code:

{{{
#!python
from django.http import HttpResponse
from django.contrib.auth import get_user_model


async def test_check_password(request):
    user = await get_user_model().objects.aget(id=1)
    is_correct = user.check_password('123456')

    return HttpResponse(is_correct)
}}}


== Significance:
1. When `settings.PASSWORD_HASHERS` changes, `check_password` and related functions can be called normally in an asynchronous environment.
2. Lay the foundation for the future `django.contrib.auth` module to support native asynchrony.


== Solution:
Add `acheck_password` method, this method will call the async setter function to update the password field of the user table when the `settings.PASSWORD_HASHERS` is changed.


== Demo
I simply implemented the solution mentioned above and put it here for reference.
https://github.com/HappyDingning/django/tree/acheck_password


== Related discussions:
https://forum.djangoproject.com/t/add-async-support-for-abstractbaseuser-check-password/20364

Thanks to bigfootjon, carltongibson and UriahKingsley
"	Bug	assigned	contrib.auth	4.2	Normal		async auth check_password	Carlton Gibson Jon Janzen	Unreviewed	0	0	0	0	0	0