[Cosmo-dev] Item.uid and icalendar UID

[Randy Letness]

There is a bug (https://bugzilla.osafoundation.org/show_bug.cgi?id=7000)
that contains some discussion about how an event's UID relates to
Item.uid.  Currently, we index the UID present in the .ics file in a 
separate
table, and generate another unique identifier for Item.uid.  This allows
for the same event (with the same icalendar UID) to exist in separate
calendars on Cosmo. 

The bug talks about setting Item.uid with the UID contained in
the event .ics data.  If we do this, then the same event (with the same
icalendar UID) cannot exist in multiple calendars on Cosmo because
these events would have the same Item.uid, which fails the unique
constraint of Item.uid.  Unlike Chandler, Cosmo does not allow the same
event to be a member of multiple calendar collections.

So the question is: should Cosmo allow multiple calendars to contain
events with the same icalendar UID, making sure the UID is unique
within the same calendar collection?  This means that Item.uid must
contain a separate unique identifier in addition to the event's UID.
Or should Cosmo enforce unique icalendar UIDs across calendars
(with Item.uid set to the event UID)?

-Randy