No feedback when subscribing to invalid calendar

[JulienPalard]

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Steps to reproduce

1. Open the calendar app
2. Click New calendar (+) then New subscription from link (read only)
3. Give https://discuss.afpy.org/discourse-post-event/events.ics (but as it could change so I'm hosting a mirror of the current version here: https://mdk.fr/x/events.ics)

Expected behaviour

As the ICS contains an invalid line (line too long) I expected an error to be shown, maybe at subscription time, and then if an error occur later, I expect a red ⚠ near the calendar to tell the user this subscription cannot be fetched and why, so the user can fix or report the issue upstream.

Actual behaviour

Nothing happen, the calendar gets added with the other, and as no events is parsed no even are displayed. No errors are reported (neither in the logs or the user interface).

Server configuration

No idea, I'm not admin on the machine ☹

Client configuration

Browser: Firefox 96.0.1 Operating system: Debian bookworm

Logs

Logs tells it cannot be parsed, but don't tell why, we can learn more by removing the broad except here:

https://github.com/nextcloud/server/blob/215aef3cbdc1963be1bb6bca5218ee0a4b7f1665/apps/dav/lib/CalDAV/WebcalCaching/RefreshWebcalService.php#L274-L278

[tcitworld]

Initial refreshment of the subscription happens through an event listener after we saved it into the database, but this can't be changed since it's handled directly by Sabre. We would need to intercept the subscription creation through a Sabre plugin.

[b90g]

nextcloud/calendar#3916 event nextcloud 22>24 Upgrade didnt bring any change to that closed issue, i dont know how to troubleshoot that or where to get the information people here need to fix things.

more verbosity is needed.

i dont think i can move a city government to change their IT systems, so people can subscribe to it on nextcloud... ;(

[szaimen]

Hi, please update to 24.0.9 or better 25.0.3 and report back if it fixes the issue. Thank you!

My goal is to add a label like e.g. 25-feedback to this ticket of an up-to-date major Nextcloud version where the bug could be reproduced. However this is not going to work without your help. So thanks for all your effort!

If you don't manage to reproduce the issue in time and the issue gets closed but you can reproduce the issue afterwards, feel free to create a new bug report with up-to-date information by following this link: https://github.com/nextcloud/server/issues/new?assignees=&labels=bug%2C0.+Needs+triage&template=BUG_REPORT.yml&title=%5BBug%5D%3A+

[simonspa]

I am experiencing this issue in NC25.0.3

[tcitworld]

@szaimen This issue needs a lot of changes, it's not a small bug.

[szaimen]

Fine by me. I'll add the tech debt label then