For servers where calendars cannot be created, the test will take the first available calendar it finds and wipe it. That is not acceptable without the user explicitly configuring that this is OK.
Status: Known issue, needs upstream investigation Priority: Low (doesn't block caldav work)
Nextcloud does not allow reusing a UID after deletion — the internal database retains the constraint even after the CalDAV object is deleted. This causes intermittent UNIQUE constraint violation errors (500) when ServerQuirkChecker.check_all() deletes and recreates test objects with the same UID.
This violates CalDAV RFC expectations and is a Nextcloud bug. Restarting the Docker container resolves it by clearing internal state.
- Search Nextcloud issue tracker for similar reports
- File upstream bug report with reproduction steps
- Consider adding server quirk detection in caldav_server_tester
- Document workaround: avoid UID reuse with Nextcloud, or restart container between test runs