Redirect loop with @permission_required and redirect_authenticated_user

[Nick Pope]

The redirect_authenticated_user option was added by ticket #12233.
When combined with @permission_required and the user does not have the specified permission(s), a redirect loop can occur.

We should document (and add tests) for this behaviour and recommend the following pattern to avoid the issue:

@login_required
@permission_required('permission', raise_exception=True)
def view(request):
    # ...

Documentation to be updated:

• ​https://docs.djangoproject.com/en/2.0/topics/auth/default/#django.contrib.auth.views.LoginView
• ​https://docs.djangoproject.com/en/2.0/topics/auth/default/#the-permission-required-decorator

[Nick Pope]

​PR

[Tim Graham <timograham@…>]

In df90e46:

Fixed #29212 -- Doc'd redirect loop if @permission_required used with redirect_authenticated_user.

[Tim Graham <timograham@…>]

In 61fc315:

[2.0.x] Fixed #29212 -- Doc'd redirect loop if @permission_required used with redirect_authenticated_user.

Backport of df90e462d91d3a77aa89b69d791bf17c2bf7ff9b from master