[Cosmo-dev] recurring events in multiple collections

[Randy Letness]

This bug:

http://bugzilla.osafoundation.org/show_bug.cgi?id=10209

describes a problem where event modifications can exist in different 
collections than the parent item.  I've checked in a fix for this that 
keeps all new data in sync, but the question now is what do we do with 
existing data on hub? 

Currently there are about 26 modifications that are "out-of-sync" with 
the parent items.  What this means is that one collection will show the 
modification and another won't.  What problems does this cause?  Users 
may see unexpected things when using cosmo ui or caldav as these 
modifications may show up in some collections and not others.  For 
example, a morse code subscribe may return one modification and an atom 
or caldav query may return the same modification, plus additional 
modifications that exist in other collections but not in the current 
collection.

So should the data migration include logic to fix this?  It would 
involve going through all the event modifications and making sure they 
exist in all collections that the parent is in.  Its not trivial, but 
not too complicated either.  Should this be included in the 0.7 
migration?  Do we live with these out-of-sync modifications?  Do we not 
worry about it for preview and if it becomes a problem fix it later?

-Randy