[oCIS] Cannot sync file to the server when content is updated to empty content

[Salipa-Gurung]

Pre-submission Checks

• I checked for similar issues, but could not find any. I also checked the closed issues. I could not contribute additional information to any existing issue.
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Describe the bug

Desktop client cannot sync the file when the file is updated to have empty content.
From #7940 (comment)

Expected behavior

Updated empty file should be synced to the server.

Steps to reproduce the issue

1. create a new text file with some content in the server
2. add that account to the client
3. from desktop client, update that file to have empty content and save
4. wait for sync

Screenshots

Logs

ownCloud.log

Client version number

ownCloud 5.2.0.12726 f6cca1
Libraries Qt 6.4.3, OpenSSL 3.1.2 1 Aug 2023
Using virtual files plugin: wincfapi
OS: windows-10.0.19045
QPA: windows

Desktop environment (Linux only)

No response

Client package version and origin (Linux only)

No response

Installation path (Windows only)

No response

Server information

Infinite Scale 5.0.0-beta.1 Community

Additional context

No response

[michaelstingl]

500 server error? Move to oCIS repo?

[ScharfViktor]

I could reproduce on server

• admin creates file new.txt with content
• admin uploads empty file new.txt using replace

Actual: 500 error. ocisLog:
2023-12-18T14:46:02+01:00 ERR error touching file name=com.owncloud.web.ocdav path=/ request-id=875ae3f6-91a1-499c-b071-cf153d28330c service=ocdav spaceid=1a4ae7f8-f0d0-4d44-9bfc-1c5aec80c09a$80d83e72-2c7a-49d5-88b4-092e968948e3 status={"code":7,"message":"touch file: error: already exists: 8afd09d8-699b-447d-a084-a4fcdf652335","trace":"00000000000000000000000000000000"} traceid=00000000000000000000000000000000

Screen.Recording.2023-12-18.at.14.45.49.mov

[micbar]

Confirmed that this is a bug. Needs fixing.

[saw-jan]

Retested with the latest master. The 500 error seems to be fixed but there's another problem.
Replacing existing file with empty file gives 201 but the previous file content is still there ❌

Web:

Desktop client: file content is empty in the file explorer but in the web there is content (adding new sync connection syncs the file content)

CC @aduffeck

[aduffeck]

@saw-jan yes, I can reproduce the problem. Seems to be a bug in a different part of the stack. looking into it

[aduffeck]

Fixed by cs3org/reva#4448