1795720 - CalDAV Calendar Events Randomly Disappear (NextCloud)

Status: RESOLVED DUPLICATE of bug 1694709

(Calendar :: Provider: CalDAV, defect)

Description

[Gunter Ohrner]

Attachment: Example Calendar View in Thunderbird

User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Safari/537.36

Steps to reproduce:

Configure one or more CalDAV calendars in Thunderbird.

(In my case the server is NextCloud 24.0.6.)

Actual results:

Thunderbird does not show some events of some calendars, even after a fresh / full sync and sometimes even events created through Thunderbird. The events are also missing from the Agenda view and from the event list above the calendar view.

I didn't see any pattern so far, unfortunately.

The events show up just fine in NextCloud's web UI itself and on an Android smartphone using DAVx^5.

Expected results:

All events in the calendar should also be visible in the Thunderbird calendar. Otherwise, it's extremely dangerous with a high risk to miss important appointments or reminders.

Comment 1

[Gunter Ohrner]

Attachment: Calendar View of the same time / day range in NextCloud

Comment 2

[Gunter Ohrner]

Forgot to add: I observe this behaviour since upgrading to Thunderbird 102.x.

I didn't notice something similar with the Thunderbird 9x / 7x series.

Comment 3

[Magnus Melin [:mkmelin]]

Might be fixed by a few patches that landed recently, like bug 1792923.

Comment 4

[Gunter Ohrner]

Attachment: Screenshot_20221021_165117.png

(In reply to Magnus Melin [:mkmelin] from comment #3)

Might be fixed by a few patches that landed recently, like bug 1792923.

As I understand, bug 1792923 is supposed to be fixed in 102.4, which was just offered to me as an update.

At least for me it doesn't fix the display, that's how the view above looks at the moment, please see the attachment.

On the first day, one of the missing events is actually shown now, while on the second day an additional event got lost... :-(

This totally erratic behaviour makes it impossible for me to rely on the Thunderbird calendar at the moment...

Comment 5

[Gunter Ohrner]

(And of course, many appointments are simply still missing, in the previous screenshot and now.)

Comment 6

[Peter Weilbacher]

I was just going to file a new bug, but found this one. I have the same issue.

I am running TB from the beta channel on Linux (currently 107.0b2 20221024145153) and for my my CalDAV events are often also not visible.

Until today's update (before I had TB107.0b1 20221018115054), a possible workaround was to disable the calendar (through right-click Properties -> remove [ ] Enable this Calendar) and then clicking on "enable" in the calendar list. Since today this no longer works. Actually, unselecting Enable in the dialog no longer even let's the calendar events disappear!

Sorry, if this is not helpful. Please let me know how I can help debugging!

Comment 7

[Gunter Ohrner]

(In reply to Peter Weilbacher from comment #6)

Until today's update (before I had TB107.0b1 20221018115054), a possible workaround was to disable the calendar (through right-click Properties -> remove [ ] Enable this Calendar) and then clicking on "enable" in the calendar list. Since today this no longer works.

This was one of the first things I tried, and it never worked for me. I'm on TB 102.x (latest stable release offered by the integrated updater).

Which CalDav server are you using?

Comment 8

[Peter Weilbacher]

It is a Nextcloud instance.

Comment 9

[Gunter Ohrner]

This still happens with 102.7.2.

Comment 10

[richard+bugzilla]

This is caused by buggy code in Nextcloud not TB. I think the bug report here can be closed.

The "upstream" fix is at https://github.com/nextcloud/server/pull/38639 and will be merged soon.

Comment 11

[Gunter Ohrner]

(In reply to richard+bugzilla from comment #10)

This is caused by buggy code in Nextcloud not TB. I think the bug report here can be closed.

The "upstream" fix is at https://github.com/nextcloud/server/pull/38639 and will be merged soon.

No, that's not the case as far as I understood.

This PR only fixes a Nextcloud bug which was introduced in NC 26, but as stated above in the bug descriptions, this "disappearing events" bug already occurred together with NC 24 and also 25.

So if the new bug in NC 26 didn't replace some other from older NC releases, the PR probably will not fix this issue.

I'm not yet on NC 26, so I was not able to test so far.

Comment 12

[richard+bugzilla]

The bug is also occurring on Nextcloud 25 according to the original issue: https://github.com/nextcloud/server/issues/36644

Be assured that the linked PR will be backported to all affected versions and will be included in patch releases (e.g. 25.x.x and 26.x.x etc.). So far nobody reported the bug for Nextcloud 24 though. Can you confirm that 24 is affected as well?

Comment 13

[richard+bugzilla]

Regarding the backport to Nextcloud 25: I'll test it and see if it really is the same bug or a new one. In the meantime, I agree to keep the issue open. There might be more unknown bugs.

Comment 14

[molgaard]

Incidentally, I just had this happen with TbSync towards an Office365 mail account.

I don't know if this is relevant for this report, though, as I don't know to what extent TbSync utilises Thunderbird code.

Comment 15

[Peter Weilbacher]

Since this bug was filed back in mid October before Nextcloud v25.0.0 was even published, I don't think this can be a server-side issue, or at least not only.
The Nextcloud hosting my calendar in question is currently v25.0.6 (with calendar module v4.4.2), I'm told. (It was probably v24 or lower when I commented on Oct 25.)

I'm now on TB v115.0b3 and still see this from time to time. My workaround is to switch off offline support for the relevant calendar, go to a different week/month, switch it back on, and go back to today. Takes a few minutes because the calendar is rather large (?) but makes all events appear also in TB.

Comment 16

[tomdereub]

Same bug here, with thunderbird 102.12.0, and Nextcloud 25.0.6. Thanks for the workaround @Peter Weilbacher, it's working for me : just switching off offline support, sync calendars, switch on, sync calendars.
But it's really annoying that I can't trust my calendar on thunderbird anymore...

Comment 17

[Sisim Biva]

Apparently, the patch is successful (https://github.com/nextcloud/server/issues/36644#issuecomment-1595691432) and will be implemented in 26.0.4 (probably in the coming weeks as the RC1 was published yesterday): https://github.com/nextcloud/server/issues/36644#issuecomment-1617523511

Nevertheless, there are still doubts if there is another bug, so the issue is still open (https://github.com/nextcloud/server/issues/36644#issuecomment-1600352404)

Comment 18

[Gunter Ohrner]

Just an update, Thunderbird 115 seems to fix this issue for me.
(Or at least the problem appears much, much more rarely now, but it really looks as if it's fixed.)

Can someone else try with 115 and confirm?

Comment 19

[Peter Weilbacher]

It just happened again for me, with TB v115.1.1 on Linux. (Toggling the offline option twice again proved a valid workaround.)

The corresponding Nextcloud instance was not yet updated to a version that has the aforementioned fix.

Comment 20

[phaidros]

Might be related: https://bugzilla.mozilla.org/show_bug.cgi?id=1713625

The bug happens here also, toggle offline-mode "fixes" the issue for an unknown amount of time.
This bug is really problematic, as C level is already pondering about going back to google office :/

Comment 21

[elliott.partridge]

I'm experiencing this on Windows 10 with Thunderbird 115.5.2. Peter's workaround seems to work. I'm considering disabling Offline Support entirely, because I can't continue constantly doubting the veracity of my calendars.

Comment 22

[Elijah]

Adding that I am also experiencing this with Thunderbird 115.7.0 on Windows 11. The CalDAV server is Fruux. Events are displayed correctly on synced Android calendars and in the Fruux web-view, but not in Thunderbird. Toggling "Offline Support" setting did fix it, although it took several minutes for all calendars to repopulate. What exactly are the downsides of disabling Offline Support? Does that mean there's no local cache of events at all?