Handle malformed ical events

[MelissaAutumn]

Sentry error:
https://thunderbird.sentry.io/issues/6058269302/events/222965a6d0b44d16b9ad497447b81a02/?project=4505428124827648&referrer=issue_details.related_trace_issue

It seems like some caldav servers can provide malformed events but also error out on requesting them? It's a pretty weird error message, we should at least look at potential solutions here.

[devmount]

Ical data was modified to avoid compatibility issues
(Your calendar server breaks the icalendar standard)
This is probably harmless, particularly if not editing events or tasks
(error count: 32 - this error is ratelimited)

This is indeed a weird message. We could just try-catch the calendar.search(...) for now and properly error out, that no events could be retrieved. Would be interesting to know, what exactly was breaking the ical standard.

[MelissaAutumn]

Ah this is a log error not an exception:
https://github.com/python-caldav/caldav/blob/c5899b5cb725d241ee4e68c5fefdcd28cbb7f7f8/caldav/lib/vcal.py#L102

Additionally there's an (empty) issue about it here: python-caldav/caldav#266

If python-caldav uses a separate logger we could mute it (I actually haven't looked into how loggers fully work in python...), or we could submit a patch to add a config option like suggested in the ticket.

[devmount]

Oh I see! Providing a patch to make that configurable might be the best solution for everyone. In the meantime we could indeed just mute the caldav logger. I think you can simply do it like this:

logger = logging.getLogger('caldav')
logger.setLevel(logging.DEBUG)

[MelissaAutumn]

I think setting the log level to critical should fix that for us.

[devmount]

Ahm, yes of course 😅

[tobixen]

Perhaps it could be downgraded to error again, as the last release of caldav library sends sends this as warnings :-)

[devmount]

Ah thanks for letting us know! We already planned upgrading to caldav 1.4.0 in #757