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kewisch / gdata-provider

Provider for Google Calendar
https://addons.thunderbird.net/thunderbird/addon/provider-for-google-calendar/
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ics time zone local time import in Thunderbird shows up as UTC in google calendar #668

Closed yEP-NL closed 4 months ago

yEP-NL commented 9 months ago

I received an ICS-file much like this:

BEGIN:VCALENDAR VERSION:2.0 METHOD:PUBLISH BEGIN:VEVENT STATUS:CONFIRMED ORGANIZER: Example DTSTART:20231018T173000 DTEND:20231018T220000 LOCATION: example place UID:00000 DTSTAMP:20231015T120000 SUMMARY: your example event CLASS:PUBLIC END:VEVENT END:VCALENDAR

On Windows 10 with dutch locale nl-NL, I double clicked the ics file and imported it in Thunderbird with gdata-provider installed. The import dialog in Thunderbird shows the start and end times as 17:30 and 22:00.

After finishing the import in my Google calendar the times are shifted to 19:30 and 00:00. That's the 2 hours difference between UTC and my local time.

After checking the iCalendar specs and testing the Google API on https://developers.google.com/ my observation is as follows.

  1. The ics-file contains DTSTART and DTEND datetimes without a time zone specified. This is a valid notation, to be interpreted as "local time".
  2. Thunderbird/addon displays the times "as is". Seems ok to me.
  3. The addon uses the Google API to register the event in my Google calendar. This leads to the time shifting by 2 hours.

Since the Google API requires specifying time zone data, I suggest the addon should compensate for the ambiguous data in the ics-file. Considering the addon dialog displays the times unmodified, I'd expect the addon to send the data to the API including the current time zone Thunderbird is using.

Notes:

kewisch commented 5 months ago

Thanks for reporting! Can you enable debug logging and share the exchange that occurs when the event is uploaded?

github-actions[bot] commented 4 months ago

It looks like we haven't heard back on this issue, therefore we are closing this issue. If this problem persists in the latest version of Thunderbird and the Provider for Google Calendar, please re-open this issue.