uploading option "delete file from source folder" deletes files even when upload fails

[mooseyboots]

⚠️ Before posting ⚠️

• This is a bug, not a question or an enhancement.
• I've searched for similar issues and didn't find a duplicate.
• I've written a clear and descriptive title for this issue, not just "Bug" or "Crash".
• I agree to follow Nextcloud's Code of Conduct.

Steps to reproduce

1. In the android client, in a new folder, click + ("Add to nextcloud")
2. "Upload files"
3. For "Upload option", select "Delete file from source folder"
4. Select all files in a media directory
5. Ssome uploads fail: of 2000 or so files, only around 10-20% have any data, the rest are 0 byte files
6. The client still deletes all files from the source folder despite uploads failing, resulting in data loss.

Expected behaviour

If any uploads result in 0 byte files, the client should not delete from source folder.

Actual behaviour

All files are deleted from source folder, regardless of whether a given file was successfully uploaded or not, resulting in data loss.

Android version

12.0.0

Device brand and model

Huawei ELE-L29

Stock or custom OS?

Stock

Nextcloud android app version

33.0.0

Nextcloud server version

31.0.8

Using a reverse proxy?

I don't know

Android logs

No response

Server error logs

[no app in context] Error: Expected filesize of 40960000 bytes but read (from Nextcloud client) and wrote (to Nextcloud storage) 34029568 bytes. Could either be a network problem on the sending side or a problem writing to the storage on the server side.
	PUT /remote.php/dav/uploads/nina/d6b6d54533bc17efc7e85d560cbe068c/000002
	from 177.63.108.32 by nina at Feb 23, 2026, 5:12:48 PM
[no app in context] Error: Expected filesize of 40960000 bytes but read (from Nextcloud client) and wrote (to Nextcloud storage) 23994368 bytes. Could either be a network problem on the sending side or a problem writing to the storage on the server side.
	PUT /remote.php/dav/uploads/nina/89b5e1ea4403203208a9f6e369982d4d/000001
	from 177.63.108.32 by nina at Feb 23, 2026, 4:20:32 PM
[no app in context] Error: Expected filesize of 40960000 bytes but read (from Nextcloud client) and wrote (to Nextcloud storage) 7307264 bytes. Could either be a network problem on the sending side or a problem writing to the storage on the server side.
	PUT /remote.php/dav/uploads/nina/86352686bfb366cf5c8c9cc187012e8b/000001
	from 177.63.108.32 by nina at Feb 23, 2026, 3:23:52 PM
[no app in context] Error: Expected filesize of 40960000 bytes but read (from Nextcloud client) and wrote (to Nextcloud storage) 38682624 bytes. Could either be a network problem on the sending side or a problem writing to the storage on the server side.
	PUT /remote.php/dav/uploads/nina/18736d3781f24f6cbed2d88f792417c2/000009
	from 177.63.108.32 by nina at Feb 23, 2026, 3:22:42 PM

Additional information

Unfortunately I don't have access to the user's device to provide logs. (I'm admin.)

While 1000s of 0 byte files were created, there were only 4 errors in the logs.

Our nextcloud is on a Yunohost server.

I'm unsure why the 0 byte file uploads occurred, I've never had that issue before. (Would also like to solve it.)

I guess you might want to say that the user shouldn't try to do that (they should use auto-upload), but nonetheless, the app lets them do it.

[mooseyboots]

not sure if related to nextcloud/server#3056, or nextcloud/ios#1395.

[mooseyboots]

I would also be interested in knowing how the client deletes the data on the device, and if it is worthwhile for the user to try to pay someone to recover it.