bug(kronolith): CalDAV-created appointments duplicate on resync in Thunderbird

[ralflang]

Summary

Appointments created in Thunderbird via CalDAV display correctly in the Horde 6 web interface on first sync. However, on subsequent resync in Thunderbird the appointment appears twice, and the duplicate then propagates back to the Horde web interface.

Appointments created in Horde web UI sync correctly to both ActiveSync (Android) and CalDAV (Thunderbird). Appointments created via ActiveSync (Android) also sync correctly to CalDAV. The issue is specific to the CalDAV inbound path.

Suspected Cause

The appointment UID or href returned to the CalDAV client after creation may not match what the client expects on subsequent REPORT/sync, causing Thunderbird to treat the existing appointment as new.

Reproduction

1. Create an appointment in Thunderbird calendar connected via CalDAV to Horde 6
2. Appointment appears correctly in Horde web interface
3. Resync Thunderbird -- appointment now appears twice in Thunderbird
4. Duplicate propagates back to Horde web interface

Environment

• Horde 6 (current FRAMEWORK_6_0)
• Thunderbird CalDAV client
• ActiveSync path (Android) works correctly for same calendar

Reported by: Ruud (via direct message)

[rjb0385]

This problem still exists. Is there any hope it can be solved?

I tried also another caldav client. On my Android phone, Fdroid app calender (org.fossify.calender version 1.10.3). This application seems to work correctly.