Task with local change, deleted on server: sync conflict does not get resolved

[Windkracht8]

I get some tasks that get stuck in synchronization, there would be a task with local changes, and it is deleted from the server by a different client. During sync DAVx5 tries to update it on the server with a conditional PUT, the server (davical) replies with a 412:

:Response status 412 for PUT /davical/00000000000000000000000000000001.ics
Server: 1.1
DAV: 1, 2, 3, access-control, calendar-access, calendar-schedule
DAV: extended-mkcol, bind, addressbook, calendar-auto-schedule, calendar-proxy
X-DAViCal-Version: DAViCal/1.1.12; DB/1.3.5
Content-type: text/xml; charset="utf-8"


No resource exists at the destination.

DAVx5 does not process this response and just keeps sending the same request. Also when it receives a full object list without that task in it, it does not realize what is going on:
davx5-log.txt

In the end I solve it by disabling the calendar, perform a sync, enable it again and do another sync. After that the task is gone and there are no more conflicts.

It would be nice if DAVx5 would realize what is happening and resolve the sync conflict.

[rfc2822]

Tracked in #2739