ModelAdmin should be able to use a non-default manager
At the moment the change_view and delete_view methods of
ModelAdmin in django/contrib/admin/options.py both use the
default manager of the model when retrieving an instance for
change or deletion. However, there is a "queryset" method on the
same class that is used to get the list of models to display in
the changelist. This means that to remove certain instances from
the admin one has to both update the queryset method to filter
them out and then change the 3 has_*_permission methods. This
doesn't seem very DRY to me.
I propose changing the change_view, delete_view and history_view methods so
that they simply use the queryset returned by the queryset method
instead of the default managers. This means that an filters put
on the queryset by the queryset method are honored and there is
thus only one place to change when you want to remove a subset of
objects from consideration.
This seems like a useful change to make to me and I can't see any
problems it would create but maybe I'm missing something...