[KPhotoAlbum] Cycles in member maps

[Robert L Krawitz]

   Date: Wed, 04 Apr 2007 16:02:43 +0300
   From: Tuomas Suutari <thsuut at utu.fi>

   Hello everyone.

   I've been thinking to deny cycles in KPhotoAlbum's member maps. (For 
   example tag A is member of B, B is member of C, and C is member A.)
   (Actually I have a code for this already, but it's not committed yet.)

   Few reasons to remove cycles:
   (1) They make some code more complicated, especially in SQL backend.
   (2) They could confuse users.
   (3) They make no sense... Or do they?

   Can you think any (even remotely) good reason to have cycles in member 
   maps or would anyone be happy if those weren't allowed?

I can't think of any even potentially good reason for this, and it
could lead to all manner of subtle bugs.

   And by the way, this would also deny A being a member of A, just like in 
   this post:
   http://mail.kdab.net/mailman/pipermail/kphotoalbum/2006-November/002571.html