[Bug]: exception thrown instead of conflict dialog on link shares

[max-nextcloud]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

When uploading a conflicting file to an editable link share the conflict dialogue does not show. Instead there are exceptions in the dev console:

Steps to reproduce

1. Create a folder
2. Share the folder via public link with edit permissions and password.
3. From a browser without open session we upload a file.
4. Upload a file with the same name
5. Instead of the conflict dialogue appearing, we get an error

Expected behavior

Show conflict dialogue without exceptions.

Nextcloud Server version

30 - cloud.nextcloud.com

[max-nextcloud]

The effects are very similar to #46848 in 29 - but the cause is probably different.

[max-nextcloud]

Resolved by #49924