UTC Timezone shouldn't use TZID=UTC;

[David Riediger]

According to this documentation

https://icalendar.org/iCalendar-RFC-5545/3-2-19-time-zone-identifier.html
https://icalendar.org/iCalendar-RFC-5545/3-3-5-date-time.html

TZID shouldn't be used with UTC instead the value should end in a 'Z'

Code like this

e.dtstart = Icalendar::Values::DateTime.new(start_at.utc, 'tzid' => "UTC")
e.dtend = Icalendar::Values::DateTime.new(end_at.utc, 'tzid' => "UTC")

generates this

DTSTART;TZID=UTC;VALUE=DATE:20230820
DTEND;TZID=UTC;VALUE=DATE:20230821

Which could be my mistake but I would assume the library would handle that for me. However it looks like if I were to provide a formatted date that ended in a Z the DateTime initializer would automatically add tzid UTC.

https://github.com/icalendar/icalendar/blob/v2.5.2/lib/icalendar/values/date_time.rb#L14

[Ryan Ahearn]

The output of dtstart and dtend looks like they are dates, rather than date times. Dates don't have a concept of timezones so the TZID is just an unknown param that gets passed through.

This code outputs the datetime with the correct Z appended:

t = Icalendar::Values::DateTime.new Time.now.utc, 'tzid' => 'UTC'
t.value_ical
"20230905T204403Z"

Can you share more about the context where you're seeing this issue?

[Ryan Ahearn]

Cleaning up abandoned issues. Please re-open if this is still something to look at.