This class would belong more appropriately within the 'user' API
(core_user) instead of within the 'core' API, since it is
directly related to user data.
Since the class has only just been added to Moodle, now is a good
time to move it.
In all cases changes have been kept to a minimum while not making
the code completely horrible. For example, there are many instances
where it would probably be better to rewrite a query entirely, but
I have not done that (in order to reduce the risk of changes).
Under certain conditions, users marked as not confirmed yet may be
returned as forum notification recipients. Such users are considered as
inactive though and the delivery adhoc task cannot be run as these
users, throwing an exception.
The solution is to make sure that fetch_subscribed_users() does not
include unconfirmed users, similarly to what was done for suspended
users and nologin users.
The added unit test also checks for deleted users. But these should
never be returned as subscribed because we consider enrolled users only
and deleted users are filtered out implicitly.
We cannot deliver notifications to users who had subscribed to a forum
or discussion and were later inactivated either by suspending or setting
the auth method to nologin. The deliver adhoc task cannot be run as
these users, throwing the "Suspended account" exception.
The solution is to make sure that fetch_subscribed_users() does not
include those inactive users.
Julien Boulen