[Cosmo-dev] ics UUID summary and preview proposal

[Jeffrey Harris]

Hi Ted,

>>  If we feel this is a major issue for interop, my backup preference
>> would be to have Cosmo hide all but the first icalUID in a given
>> collection when it's accessed by CalDAV, because this wouldn't impact
>> the Desktop.
> 
> It seems like we are agreed on punting, but I would point out that your
> backup preference does impact the server, which is the thing holding up
> Preview - as in, every day the server slips, so does Preview.  None of
> us wants to be taking on new work at this point, but it's important for
> all of us to be focused on getting to Preview as quickly as possible.

Agreed, we're all in this together, I apologize if it appeared I was
trying to offload work.

I should've been a little more clear; my guess is that making changes to
Desktop sharing to handle collisions in icalUID differently would take
an order of magnitude more work than doing what I was suggesting on the
server (although I'll admit I haven't looked at Cosmo's CalDAV code, so
that's an uneducated guess).  Also, my confidence that changes on the
Desktop wouldn't destabilize sharing isn't high, hence my preference for
changing not-core-to-Preview CalDAV.

However, until Randy pointed it out, I hadn't considered his point that
if we're going to disallow duplicate icalUIDs in collections at some
point, we'll have to handle existing collections that violate that
constraint.  With that in mind, it seems this decision may have a long
term impact, so I feel less secure about punting.

I think uniqueness of UIDs (whether "universally" unique UUIDs or
iCalendar UIDs, "globally" unique according to the iCalendar spec)
access controls, and how uniqueness is scoped on Cosmo (per collection
soup? per user soup? per server instance soup?) are inextricably linked
topics we're going to want to talk more about after Preview, but it'd be
really great to not go down that road now, so I'm left feeling uncertain
about what to do on this icalUID issue for Preview.

Sincerely,
Jeffrey