Comment 1 for bug 79907

There are two distinct problems here.

One problem is the assertion error. It is a bug in our iCalendar parser. It
happens when there is a recurring event with more than one exception date. I've
marked the location of the bug with an XXX comment that includes a proposed fix;
it remains to write a regression test for this bug and apply the fix. (See the
checkin for revision 3533).

Another problem is character-set related. The iCalendar spec (RFC 2445) says
that the default charset of iCalendar files is UTF-8, but it can be overriden
with MIME Content-Type headers. The Zope 3 infrastructure that implements HTTP
PUT does not pass the Content-Type request header to our code and we always
assume the data is in UTF-8. It is possible that Sunbird sends data in some
other encoding and specifies it in the header.

Fixing this other problem might require some changes in Zope 3.