Custom permission set mess
 

I have quite a few usergroups and forums on my board, and for example the guest group has the 'Can view forums' permission but none of the read topics / post etc. to ensure we explicitely have to allow guests to read / post stuff.

Because of permission inheritance, all forums are visible (just the names and post / thread counts) to guests. On the other hand, disabling the 'Can view forums' permission can't be rectified through custom permission sets on the forums destined for guests, as it basically disables ALL pages when set per usergroup. Sounds like a design error to me.

If this can be solved in some other way than depicted below, please tell me. But I don't like making hundreds of custom permission sets just to deny people from viewing the name and post/thread counters of a forum.

I decided to make a plug-in that would check if the user can read a forum's threads, if not, it would remove the permission to view the forum.

It uses the admin_cache_forum_perms hook and is very simple:

However, this stops working after a certain time and guests see the whole list again! Somehow there must be a place where the function calling this hook is bypassed... or the cache is just bypassed. Very weird, because the forumcache datastore is only updated in that function. Any ideas on this one ?