Push subscription registration doesn't work (The input element to parse is empty.)

[Offerel]

Starting with 4.5.9, the app can't register for any push service anymore. This issue doesn't happen with 4.5.8, but with 4.5.9 and 4.5.10. Downgrade to 4.5.8 solves the issue. The issue is also described at bitfireAT/nc_ext_dav_push#65

Push channels registered before a upgrade, stays subscribed, but they don't refresh the subscription after it ends. Create a new calendar in a supported Nextcloud instance creates the calendar, but a push subscription is not successful. Error message on the NC instance is The input element to parse is empty. Do not attempt to parse

[provokateurin]

Can confirm that downgrading to 4.5.8 also works for me.

[Offerel]

1. Install 4.5.8
2. Connect Nextcloud account
3. Add or Create Calendar
4. Check details, it will say: Push-Unterstützung: date +time angemeldet + läuft ab date + time in future
5. Check NC error log, no error like The input element to parse is empty. Do not attempt to parse
6. Update to 4.5.9 or 4.5.10
7. Create another calendar on the same NC instance
8. Check details, it will say: push support available, but no dates. But Channels in ntfy, sunup, etc will be created
9. Check NC logfile, the error The input element to parse is empty. Do not attempt to parse will be there

If you need a NC test instance, please let me know by private message. Currently I'm on vacation, but will be back in Germany tomorrow. We can also do some rest requests and check logs together, if needed

[rfc2822]

Can't reproduce with these steps. There was one step missing at the beginning (set Push provider to Sunup or something). Tested with 4.5.8-ose and 4.5.9-ose from F-Droid and Nextclod 32 (yesterday) and 33 (today).

@Offerel Can you provide a test account on your instance? Please send over https://www.davx5.com/support.

Verbose logs would be also be very helpful:

1. Set up everything according to your steps.

2. Enable DAVx5 / App settings / Verbose logs.

3. Do steps from above:

   • Create another calendar on the same NC instance
   • Check details, it will say: push support available, but no dates. But Channels in ntfy, sunup, etc will be created
   • Check NC logfile, the error The input element to parse is empty. Do not attempt to parse will be there

4. Wait for the error in NC logs.

5. Post DAVx5 and NC logs here (if they don't contain private data) or send over https://www.davx5.com/support if they may contain private data.

[rfc2822]

I have found a strange behavior in the new Ktor dav4jvm upload method. I think it's related to this issue. Will create a dav4jvm issue.

Update: I'm now quite sure that it's bitfireAT/dav4jvm#156