Infinite retry for conflicting auto-uploads

[osovitskiy]

⚠️ 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. Configure auto-upload
2. Take some photos

Expected behaviour

If the uploaded succeeded, it should be marked as succeeded on the client side.
Even if the original attempt did fail on the client for any reason (e.g. network timeout), on retry the client should detect conflict with the existing server-side file and offer to resolve it instead of infinite retry cycle.

Actual behaviour

Files are being uploaded to the server successfully. However, they aren't marked as such on the client side and Android client tries to upload them again. Instead of detecting conflict and offering to resolve, it fails the upload due to "Unknown reason" and attempts to upload again, indefinitely.

Android version

16

Device brand and model

Samsung S22

Stock or custom OS?

Stock

Nextcloud android app version

3.35.2

Nextcloud server version

31.0.10

Using a reverse proxy?

Yes

Android logs

N/A

Server error logs

[HIDDEN] [05/Feb/2026:01:32:35 +0000] "HEAD /remote.php/dav/files/[HIDDEN]/20260201_163312.jpg HTTP/1.1" 200 802 "-" "Mozilla/5.0 (Android) Nextcloud-android/3.35.2"
[HIDDEN] [05/Feb/2026:01:32:36 +0000] "PROPFIND /remote.php/dav/files/[HIDDEN]/20260201_163312.jpg HTTP/1.1" 207 1479 "-" "Mozilla/5.0 (Android) Nextcloud-android/3.35.2"
[HIDDEN] [05/Feb/2026:01:32:36 +0000] "PROPFIND /remote.php/dav/files/[HIDDEN]/20260201_163312.jpg HTTP/1.1" 207 1479 "-" "Mozilla/5.0 (Android) Nextcloud-android/3.35.2"
[HIDDEN] [05/Feb/2026:01:32:37 +0000] "HEAD /remote.php/dav/files/[HIDDEN]/20260201_182117.jpg HTTP/1.1" 200 802 "-" "Mozilla/5.0 (Android) Nextcloud-android/3.35.2"
[HIDDEN] [05/Feb/2026:01:32:38 +0000] "PROPFIND /remote.php/dav/files/[HIDDEN]/20260201_182117.jpg HTTP/1.1" 207 1481 "-" "Mozilla/5.0 (Android) Nextcloud-android/3.35.2"
[HIDDEN] [05/Feb/2026:01:32:38 +0000] "PROPFIND /remote.php/dav/files/[HIDDEN]/20260201_182117.jpg HTTP/1.1" 207 1481 "-" "Mozilla/5.0 (Android) Nextcloud-android/3.35.2"

Additional information

I have NextCloud client installed and configured identically on multiple Android devices (same server). The only install that is affected by the bug is on a Samsung S22 phone. This phone has NextCloud client installed since ages, and the bug appeared just recently, so it looks like 3.35 client regression.
I won't have access to a PC with ADB in near future, so cannot provide client logs for now.

[alperozturk96]

@osovitskiy Hey,

I tried to reproduce the issue, but in my testing everything worked as expected. Here’s exactly what I did:

1. Configured a custom local folder (the Pictures directory) for auto-upload
2. Verified that photos were uploaded successfully
3. Manually created a sync conflict
4. Took some new pictures
5. The app uploaded all files and prompted me to resolve the sync conflict for the conflicted file
6. I did not resolve the sync conflict
7. Continued taking photos, all new photos were uploaded successfully
8. Restarted the app; it prompted me about the sync conflict again, and I canceled that upload from the Upload list (drawer menu -> Uploads)
9. Continued taking photos, again, all new photos were uploaded, and I did not receive another sync-conflict notification

From the code side: if the last upload result is a sync conflict, we mark that file as handled. This means the same file is not picked up again on subsequent runs, so we don’t keep retrying the same upload.

I tested this scenario on both an emulator and a real device and couldn’t reproduce any unexpected behavior or infinite retries.

I’m unable to reproduce the scenario you’re describing, so I suspect something else might be involved. Could you please share more details about the configured folder (path, type, any special setup), and anything else that might be relevant?

[delbonis]

I believe I might be experiencing the same issue.

Android version: 15 (CalyxOS 6.10.20, I know I know)
App version: 3.35.2
Server version: 31.0.13

Here's a few interesting logs retrieved from logcat for one of the files that is giving me the "Unknown error" in the uploads list:

$ sudo adb logcat | grep 'PXL_20260205_092406741'
02-08 15:05:49.005  4308  4530 D AutoRename: Before - /Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg
02-08 15:05:49.005  4308  4530 D AutoRename: After - /Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg
02-08 15:08:46.477  4308  4530 D AutoRename: Before - /Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg
02-08 15:08:46.477  4308  4530 D AutoRename: After - /Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg
02-08 15:08:46.477  4308  4530 V UploadsStorageManager: Updating /storage/emulated/0/DCIM/Camera/PXL_20260205_092406741.jpg with status=UPLOAD_IN_PROGRESS
02-08 15:08:46.479  4308  4530 D AutoRename: Before - /Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg
02-08 15:08:46.480  4308  4530 D AutoRename: After - /Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg
02-08 15:08:46.482  4308  4530 D UploadsStorageManager: updateUpload returns with: 1 for file: /storage/emulated/0/DCIM/Camera/PXL_20260205_092406741.jpg
02-08 15:08:46.504  4308  4530 D OwnCloudClient #0: REQUEST HEAD /remote.php/dav/files/trey/Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg
02-08 15:08:46.908  4308  4530 D ExistenceCheckRemoteOperation: Existence check for https://nextcloud.tr3y.io/remote.php/dav/files/trey/Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg targeting for  existence finished with HTTP status 200
02-08 15:08:46.908  4308  4530 E UploadFileOperation: Upload of /storage/emulated/0/DCIM/Camera/PXL_20260205_092406741.jpg to /Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg: Synchronization conflict
02-08 15:08:46.913  4308  4530 D OwnCloudClient #0: REQUEST PROPFIND /remote.php/dav/files/trey/Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg
02-08 15:08:47.438  4308  4530 D AutoRename: Before - /Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg
02-08 15:08:47.438  4308  4530 D AutoRename: After - /Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg
02-08 15:08:47.438  4308  4530 V UploadsStorageManager: Updating /storage/emulated/0/DCIM/Camera/PXL_20260205_092406741.jpg with status:UPLOAD_SUCCEEDED and result:SAME_FILE_CONFLICT (old:/storage/emulated/0/DCIM/Camera/PXL_20260205_092406741.jpg status:UPLOAD_IN_PROGRESS result:-1)
02-08 15:08:47.438  4308  4530 V UploadsStorageManager: Updating /storage/emulated/0/DCIM/Camera/PXL_20260205_092406741.jpg with status=UPLOAD_SUCCEEDED
02-08 15:08:47.443  4308  4530 D AutoRename: Before - /Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg
02-08 15:08:47.443  4308  4530 D AutoRename: After - /Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg
02-08 15:08:47.452  4308  4530 D UploadsStorageManager: updateUpload returns with: 1 for file: /storage/emulated/0/DCIM/Camera/PXL_20260205_092406741.jpg
02-08 15:08:47.456  4308  4530 D OwnCloudClient #0: REQUEST PROPFIND /remote.php/dav/files/trey/Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg
02-08 15:08:54.944  4308 10286 D AutoRename: Before - /Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg
02-08 15:08:54.945  4308 10286 D AutoRename: After - /Pictures/Phone/Camera/2026/02/PXL_20260205_092406741.jpg

I can confirm that this file was in fact uploaded when I look for it in the Nextcloud browser file explorer. I don't have logcat from when it was originally uploaded since I've restarted my phone while trying to troubleshoot. I do occasionally get notifications with "Upload failed": "Locked", but it doesn't mention the filename.

Maybe I can try to reproduce the full logs with a new picture.

---

This isn't it, but I did notice this when grepping for UploadFileOperation that's being emitted on each upload attempt. It says it's prompting me to disambiguate the conflict, but no prompt to pick the version is ever generated.

02-08 15:25:50.130 11658 11679 D UploadFileOperation: creating upload file operation, user: trey@nextcloud.tr3y.io upload account name trey@nextcloud.tr3y.io
02-08 15:25:50.130 11658 11679 W UploadFileOperation: UploadFileOperation file is null, obtaining from upload
02-08 15:25:50.223 11658 11679 D UploadFileOperation: normal upload
02-08 15:25:50.227 11658 11679 D UploadFileOperation: Checking name collision in server
02-08 15:25:50.690 11658 11679 D UploadFileOperation: Name collision; asking the user what to do
02-08 15:25:50.690 11658 11679 E UploadFileOperation: Upload of /storage/emulated/0/DCIM/Camera/PXL_20260204_112534536.MP.jpg to /Pictures/Phone/Camera/2026/02/PXL_20260204_112534536.MP.jpg: Synchronization conflict
02-08 15:25:50.690 11658 11679 D UploadsStorageManager: updateDatabaseUploadResult uploadResult: RemoteOperationResult{mSuccess=false, mHttpCode=-1, mHttpPhrase='null', mException=null, mCode=SYNC_CONFLICT, message='null', getLogMessage='Synchronization conflict'} upload: com.owncloud.android.operations.UploadFileOperation@36b48aa

I did notice that occasionally a few times in the last couple weeks when this started happening that I was being prompted to pick between the two apparently-identical versions of the file. But sometimes (not always), when I'd tap on the notification it wouldn't actually bring me to any dialog to pick.

I do see in logcat occasionally logs like:

02-08 15:54:04.361 11658 12365 E UploadFileOperation: Upload of /storage/emulated/0/DCIM/Camera/PXL_20260208_074504189.jpg to /Pictures/Phone/Camera/2026/02/PXL_20260208_074504189.jpg: File is currently locked by another user or process
02-08 15:54:04.375 11658 12365 E 🔄📤AutoUpload: ❌ upload failed /storage/emulated/0/DCIM/Camera/PXL_20260208_074504189.jpg (trey@nextcloud.tr3y.io): File is currently locked by another user or process

I have seen in the Nextcloud server logs messages like this intermittently:

• Expected filesize of 27883115 bytes but read (from Nextcloud client) and wrote (to Nextcloud storage) 26296320 bytes. Could either be a network problem on the sending side or a problem writing to the storage on the server side.
• these were coupled in pairs, looking at timestamps
  • PHP Request Startup: POST Content-Length of 9869477 bytes exceeds the limit of 8388608 bytes at Unknown#0
  • Computed md5 hash is incorrect.
• probably related to log rotation: Request used more than 300 MB of RAM: 506.4 MB

I increased some limits relating to memory and post request sizes, in case I was stumbling into these.

(fwiw, I don't see any disk errors or smart warnings on the disks backing the storage, so I don't think it's a storage problem)

After some attempts at reproducing it, I can't make it occur. When I take a picture I see in logcat all the logs that seem to suggest the upload working fine and not resulting in this weird behavior, although maybe it'll crop up later?

[brentobi]

Some additional description (incl. log snippet for one full file upload attempt): #16126 (comment).

I also observed that sometimes a single file is correctly (?) resolved when pausing uploads during retry loop. (also described + logs in linked comment)