Delete all of a user's notifications after they're deleted

[henry.wright]

Some notifications seem to remain in the database after a user is deleted. I don't see a reason to keep them? Even custom notifications added by plugins could get the chop:

function example_func( $user_id ) {
    $where = array(
        'user_id' => $user_id,
        'item_id' => false,
        'secondary_item_id' => false,
        'component_action' => false,
        'component_name' => false
    );
    BP_Notifications_Notification::delete( $where );
}
add_action( 'delete_user', 'example_func' );
// More hooks needed here to cover the various ways users can be deleted.

[DJPaul]

Yes. The rest of BP, we normally hook to wpmu_delete_user and delete_user for this, and sometimes even bp_make_spam_user if it makes sense to tidy-up after a user has been spammed.

[henry.wright]

Probably wouldn't want to do this on spamming a user just in case that action needs to be undone.

[henry.wright]

I've added a new function bp_core_delete_notifications_on_user_delete() to bp-members-functions.php. Not sure if that's the right place?

[boonebgorges]

Thanks, henry.wright! The function looks good at a glance. It ought to live in bp-notifications, because currently, if notifications is disabled, the function will produce fatal errors. Unit tests would also be rad.

[henry.wright]

Replying to boonebgorges:

...It ought to live in bp-notifications, because currently, if notifications is disabled, the function will produce fatal errors...

Right, see what you mean, but I think we might have a problem?

If the notifications component is disabled, and a user is then deleted, we'd still want the relevant items in the notifications table removed (even though notifications are now disabled, they may have been enabled at an earlier date).

[boonebgorges]

Do functions in bp-notifications fire if the notifications component is disabled?

No. But I think we shouldn't worry about that. Components can't be expected to clean up after themselves if they've been turned off. Moving all of this logic inside of bp-core is going to create all sorts of bp_is_active() headaches that I'd like to avoid. In any case, it's not going to break anyone's site if this data is not cleared up. So let's keep it in bp-notifications.

[henry.wright]

Components can't be expected to clean up after themselves if they've been turned off.

That sounds reasonable to me!

2nd patch to follow...

[Mamaduka]

Update original patch with correct PHPDoc version also added unit tests.

Sorry for direct queries BP_Notifications_Notification::get() checks agains registered components, while BP_Notifications_Notification::delete() doesn't care about that.

[boonebgorges]

In 10437:

Delete a user's notifications when the user is deleted.

Props henry.wright, Mamaduka.
Fixes #6681.