Ihor Radchenko <yantar92@posteo.net> writes:

> Side note: here, and in other places, we use "\n" as end of line. Yet,
> for example
> https://icalendar.org/iCalendar-RFC-5545/3-8-2-4-date-time-start.html
> prescribes CRLF (\r\n). Also, see
> https://orgmode.org/list/87ilgljv6i.fsf@localhost
> If you are familiar with iCalendar spec, may you look through the
> ox-icalendar code and check other places where we do not conform to the
> newline spec?

org-icalendar--vtodo is wrapped in org-icalendar-fold-string, so this
"\n" gets converted to CRLF later on.

However you are right that other parts of the iCalendar export have
inconsistent line endings. Currently, VEVENT and VTODO components have
the correct CRLF endings, but the other parts of the VCALENDAR do not
(such as the preamble).

I like your suggestion in the above thread to just wrap the whole
export in `org-icalendar-fold-string'.  Though I think it's slightly
nicer to do it in `org-icalendar--vcalendar' instead of
`org-icalendar-template'.

So, I've attached a standalone patch to do this. It also fixes an issue
with `org-icalendar-fold-string' where the last newline was missing
"\r", and adds a unit test.

Note that fixing the line endings causes a surprising compatibility
issue with org-caldav. I fixed this problem on the org-caldav side, and
made a note in ORG-NEWS.