[Bug]: macOS client does not properly delete sync database files

[ArcticFall]

⚠️ Before submitting, please verify the following: ⚠️

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

Bug description

Client does not properly delete sync database on macOS when the synchronization is deleted.

Steps to reproduce

1. Navigate into top folder of synchronization in Finder
2. Show hidden files
3. Go into nextcloud client settings and delete the synchronization
4. Observe the sync db files vanish in Finder
5. Add the synchronization back in nextcloud client settings
6. Observer sync db files appear right away again with the same size as before

Expected behavior

When deleting a synchronization the sync db files should be correctly deleted and when creating the synchronization again blank sync db files should be created.

Which files are affected by this bug

Sync db files

Operating system

macOS

Which version of the operating system you are running.

Sonoma 14.6.1

Package

Official macOS 12+ universal pkg

Nextcloud Server version

30.0.4

Nextcloud Desktop Client version

5.15.3

Is this bug present after an update or on a fresh install?

Fresh desktop client install

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

Are you using an external user-backend?

• Default internal user-backend
• LDAP/ Active Directory
• SSO - SAML
• Other

Nextcloud Server logs

Client logs

I will be happy to provide the client logs, but I don't think I can share it publicly here. Some of the filenames contain personal information.

Additional info

An employee was experiencing a sync loop, where the nextcloud client would always start synchronization but stop right away again and show that all files are synchronized, even though nothing had been synchronized. This is a bug that I think stems from the previous two disastrous client releases. Multiple people in our organization have experienced this problem, but the fix was always to just re add the synchronization. And on this employees computer it looked also like it worked, it synced for a little while and then she reported, that the client is not stuck in a loop anymore and it shows, that everything had been synchronized. After she came back from the Christmas holidays she noticed that she was missing files from her colleagues and that changes she had made weren't present on their computers. So she asked me to take a look and we encountered the above described problem. Apparently her sync db files were still corrupted and because they were not properly deleted between deleting the synchronization and adding it again, the problem persisted. even though the sync loop disappeared.

I'm only a volunteer for our organization and I don't use macOS myself, so that might be a factor here. But I think my described expected behavior is correct. Maybe there should also just be a button, that allows users to reset the sync db files.