Time zone support in `schedule_from_ical`

[epologee]

The base implementation of IceCube::IcalParser.schedule_from_ical ignores time zone identifiers, resulting in all times being parsed in the current time zone of the host.

This PR exposes the issue with a series of specs, and fixes it with a (somewhat lengthy) time zone lookup. This last part was added because the TZID strings of the iCal format don't map cleanly onto Rails time zones.

Input schedule

DTSTART;TZID=MDT:20130731T143000
RRULE:FREQ=WEEKLY;UNTIL=20140730T203000Z;BYDAY=MO,WE,FR
RDATE;TZID=MDT:20150812T143000
RDATE;TZID=MDT:20150807T143000
EXDATE;TZID=MDT:20130823T143000
EXDATE;TZID=MDT:20130812T143000
EXDATE;TZID=MDT:20130807T143000
DTEND;TZID=MDT:20130731T153000

Output schedule on master

DTSTART;TZID=CEST:20130731T143000
RRULE:FREQ=WEEKLY;UNTIL=20140730T203000Z;BYDAY=MO,WE,FR
RDATE;TZID=CEST:20150812T143000
RDATE;TZID=CEST:20150807T143000
EXDATE;TZID=CEST:20130823T143000
EXDATE;TZID=CEST:20130812T143000
EXDATE;TZID=CEST:20130807T143000
DTEND;TZID=CEST:20130731T153000

Output schedule on this branch

DTSTART;TZID=MDT:20130731T143000
RRULE:FREQ=WEEKLY;UNTIL=20140730T203000Z;BYDAY=MO,WE,FR
RDATE;TZID=MDT:20150812T143000
RDATE;TZID=MDT:20150807T143000
EXDATE;TZID=MDT:20130823T143000
EXDATE;TZID=MDT:20130812T143000
EXDATE;TZID=MDT:20130807T143000
DTEND;TZID=MDT:20130731T153000

P.S. Note that time zones will not always match the exact same string, because something like "America/Denver" will get converted to "MDT" along the way. The times will still match semantically.

[pacso]

Hey @epologee, thanks for sending this through!

I'll find some time in the next day or two to review this properly. In the mean time, can you add a changelog entry and ensure your tests pass?

[epologee]

Hi, thanks, will do / already done!

In the mean time, can you add a changelog entry and ensure your tests pass?

standardrb reports an indentation issue on lines that I did not touch (in a file I did touch), would you like me to add a commit to fix that indentation? Because the workflow needs your approval to run, I'm not sure if it passes or errors right now:

  lib/ice_cube/time_util.rb:289:18: Layout/CaseIndentation: Indent `when` as deep as `end`.
  lib/ice_cube/time_util.rb:290:18: Layout/CaseIndentation: Indent `when` as deep as `end`.
  lib/ice_cube/time_util.rb:291:18: Layout/CaseIndentation: Indent `when` as deep as `end`.
  lib/ice_cube/time_util.rb:292:18: Layout/CaseIndentation: Indent `when` as deep as `end`.
  lib/ice_cube/time_util.rb:293:18: Layout/CaseIndentation: Indent `when` as deep as `end`.
  lib/ice_cube/time_util.rb:294:18: Layout/CaseIndentation: Indent `when` as deep as `end`.

Cheers!

[pacso]

I think once you get your first PR through, you don't need approval for future PR test runs.

[epologee]

would you like me to add a commit to fix that indentation?

Update: I added a commit because the standardrb lint prevents the other tests from running.

[suzumejakku]

Hi - any chance this will be merged ?

[jankeesvw]

We are running this PR in production now, would be great to get this in master.

[pacso]

Can you resolve the failing tests? I'll then do a full review and merge it 👍🏻

Although ... these might be tests that I've broken by reverting another branch 🤔 If so ... I'll hopefully sort it soon, and release everything together.

[suzumejakku]

Hi @pacso, Did you have any chance to review this ?

[suzumejakku]

Hi @pacso Sorry to insist, but is there any way to make it into production ?

[frsantos]

Hi @seejohnrun @avit @pacso

I'm wondering... are any of you still maintaining this repo?

[pacso]

Yes, we are. However I sadly don't have time to resolve the issues on this branch. If you can push changes to fix the failing tests, I'll happily merge it.

[epologee]

I pushed a minor edit to re-run the specs. I recall that the failures looked like they weren't created by the changes in this PR, but can have another look after the workflow is approved.