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).

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

[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.