Read-only calendars: Shall local modifications (done by calendar apps) be reset?

[rfc2822]

See #600: When a calendar is read-only – should local modifications (like a reminder) that are done by a calendar app (for instance, Etar allows to add a reminder even if the event is read-only) remain or should the event be reset to the server version at the next sync?

Only when the event is changed on the server, I think it should be downloaded in any case (which will reset possible local changes).

(Same of course applies to other collection types.)

See also:

• Error adding reminder to a read-only calendar (Fastmail) #80
• Etar: Reminders in read-only calendars Etar-Group/Etar-Calendar#523
• Etar: Do not allow setting reminders on read-only calendars Etar-Group/Etar-Calendar#1368

Update: Clarified that this is not about whether calendar apps should be able to change read-only events – we don't have any influence on that. Some calendar apps allow for instance to create a local reminder even when DAVx⁵ sets the calendar as read-only (CAL_ACCESS_READ).

[chrysn]

Would it be an option to give them the same interface as ICSx⁵ has, i.e., have per-calendar options to "ignore alerts embedded in the calendar", or to "add a default alarm for all events"?

[Anachron]

Please do NOT allow for local modifications!

Imagine someone setting up a reminder on the server calendar and the local one deleted it (accidentally) and then misses an important event.

[rfc2822]

So it's better to drop such a reminder (which can be created for instance by Etar also in read-only events) on the next sync? Users will then miss their event too, relying on the alarm that's gone at next sync

[Anachron]

In a perfect world the app should not allow these modifications and ask the user to create a new local event (saved on phone for example) if the user wanted a custom alarm set.

Its fine if users create more or different alarms, just dont allow modification of the original event.

[rfc2822]

I have edited the original post. Some calendar apps allow to edit read-only events to add reminders for instance. The question is how DAVx⁵ shall deal with this.

Its fine if users create more or different alarms, just dont allow modification of the original event.

Do you mean on the server? Yes, of course.

[Anachron]

Okay, here is the situation:

• Server sends version A
• User creates version B
• Server creates and sends version C

What would you expect to happen ona read-only calendar? Surely I would want the sever version to override the reminder from the local one. It's read-only, after all.

If the user wants to modify it, he should create a new event for him.

Turning it around, if we allowed users to modify or even delete reminders, what mess do we create? How can we be sure that everybody gets their updated reminders?

[AndreKoepke]

Is it an option to ask the user about it? Or informing him that event X was deleted?

[schichtnudelauflauf]

https://chaos.social/@lasagne/112003796279811179

Linking the thread with Anachron on fedi here to duplex it.
I gave some perspective of why keep local reminders good.
Its kind half an argument. I guess Anachron didn't have time to reply yet.

To expand on that:
What are real world usecases where an upstream readonly calendar needs to be authority about reminders and not just schedules?
Is D5X used in orgs that might do that?

(I get why tossing local changes generally is simpler from a program maintenance perspective.)