[BUG] icalendar export fails with SCHEDULED/DEADLINE entries [9.5.2 (9.5.2-gbc8c3e @ /home/eliza/.emacs.d/straight/build/org/)]

[Eliza Velasquez]

Hello,

It seems like `org-icalendar-export-to-ics' fails to consider the
SCHEDULED and DEADLINE properties. Consider the following org file
`foo.org':

* foo
SCHEDULED: <2022-02-15 Tue>

When invoking `org-icalendar-export-to-ics', we get the following
`foo.ics' file.

BEGIN:VCALENDAR
VERSION:2.0
X-WR-CALNAME:test
PRODID:-//Eliza Velasquez//Emacs with Org mode//EN
X-WR-TIMEZONE:PST
X-WR-CALDESC:
CALSCALE:GREGORIAN
END:VCALENDAR

As you can see, there is no entry for `foo'. Changing the file so that
the timestamp is in the body rather than the SCHEDULED property (though
I'm not sure "property" is the correct term here, given that it's not a
PROPERTY)...

* foo
<2022-02-15 Tue>

...exports as expected.

BEGIN:VCALENDAR
VERSION:2.0
X-WR-CALNAME:test
PRODID:-//Eliza Velasquez//Emacs with Org mode//EN
X-WR-TIMEZONE:PST
X-WR-CALDESC:
CALSCALE:GREGORIAN
BEGIN:VEVENT
DTSTAMP:20220215T074144Z
UID:TS1-3d9795cd-8430-49dd-97d7-f1fcc10d814d
DTSTART;VALUE=DATE:20220215
DTEND;VALUE=DATE:20220216
SUMMARY:foo
DESCRIPTION:<2022-02-15 Tue>
CATEGORIES:test
END:VEVENT
END:VCALENDAR

I noticed this when trying to use org-caldav, and it seems some others
have run into this issue as well. At least, I'm pretty sure the two bugs
are caused by the same issue.
<https://github.com/dengste/org-caldav/issues/212>

Emacs  : GNU Emacs 29.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.30, 
cairo version 1.16.0)
Package: Org mode version 9.5.2 (9.5.2-gbc8c3e @ 
/home/eliza/.emacs.d/straight/build/org/)
--
Eliza