Re: [O] N/A; icalendar export doesn't guarantee unique UIDs

[Tassilo Horn]

Tassilo Horn <address@hidden> writes:

> For example, I have entries like
>
> *** Meeting with Max
>     :PROPERTIES:
>     :ID:       e1c32cb4-bd1f-4302-8067-1723d1958a88
>     :END:
>     <2012-03-13 Tue 12:00-13:00>
>     <2012-03-21 Wed 15:00-16:00>
>     <2012-03-29 Thu 10:00-11:00>
>     <2012-04-10 Tue 12:00-13:00>
>     <2012-04-18 Wed 11:00-11:30>
>     <2012-04-25 Wed 10:00-11:00>
>     <2012-05-10 Thu 12:00-13:00>
>
> They should show up at any date/time listed there.  That's true for the
> org agenda with `org-agenda-skip-additional-timestamps-same-entry' set
> to nil.  The icalendar export also creates multiple VEVENTS for the
> above org entry, *but they all have the same UID* (which is strictly
> VERBOTEN by the icalendar spec).  The result is that the google calendar
> only shows one appointment, and that seems to be arbitrary.  In the
> example above, it shows the meeting on 2012-04-18.

Another very related topic: Even when ignoring entries with multiple
timestamps, every icalendar item (VTODO, VEVENT, VJOURNAL) must have a
SEQUENCE number that has to be incremented when an entry changes
significantly (start, end, due, ..., see RFC 2445: 4.8.7.4).

I've read in the google calendar help group, that the google calendar
won't refresh items for which the UID is already known and the SEQUENCE
number didn't increase...

Bye,
Tassilo