1922772 - Holiday calendars have duplicate vevent uid

Status: RESOLVED DUPLICATE of bug 1921465

(Calendar :: Provider: ICS/WebDAV, defect)

Description

[Markus]

Steps to reproduce:

I'm using a calendar from https://www.thunderbird.net/en-US/calendar/holidays/

More precisely: https://www.thunderbird.net/media/caldata/autogen/AustrianHolidays.ics

Actual results:

Thunderbird only shows the holidays from 2026 in the calendar.

Expected results:

Thunderbird should show all holidays from 2024 to 2026.

The suspected problem is, that the events in the ICS file use the same UID each year.

Example:

BEGIN:VEVENT
SUMMARY:Allerheiligen 
DTSTART;VALUE=DATE:20241101
DTEND;VALUE=DATE:20241102
DTSTAMP:20240903T094721Z
UID:dd0243a517030b31124e49bfd8afc8e2
CATEGORIES:Holidays
CLASS:public
DESCRIPTION:National holiday -  Viele Kirchen ehren alle ihre Heiligen an 
 Allerheiligen\, auch Allerheiligen genannt.
LAST-MODIFIED:20240903T094721Z
TRANSP:transparent
END:VEVENT

BEGIN:VEVENT
SUMMARY:Allerheiligen 
DTSTART;VALUE=DATE:20251101
DTEND;VALUE=DATE:20251102
DTSTAMP:20240903T094723Z
UID:dd0243a517030b31124e49bfd8afc8e2
CATEGORIES:Holidays
CLASS:public
DESCRIPTION:National holiday -  Viele Kirchen ehren alle ihre Heiligen an 
 Allerheiligen\, auch Allerheiligen genannt.
LAST-MODIFIED:20240903T094723Z
TRANSP:transparent
END:VEVENT

Comment 2

[adrian.bach]

German calendar also has this problem.

Comment 3

[Markus]

This one is probably a duplicate of https://bugzilla.mozilla.org/show_bug.cgi?id=1921465

Comment 4

[Markus]

I'm not sure if, by standards, it is okay to have duplicate UIDs, or not.
So either Thunderbird fails to display them correctly, or the generated ICS are wrong. 🤨

Comment 5

[Steve Jalim]

Moved this to the appropriate BZ category so that it gets attention. Thanks for reporting!

Comment 6

[Markus]

Thanks @Steve.

Why I chose the category: I understood that this category is for Thunderbird. Since I suspect that the actual ICS is the problem, I considered it a content problem and not a problem of Thunderbird itself. But anything is okay, as long as it's brought to the attention of the right persons.