Android client fails to download files with ">" in the name

[rsevat]

⚠️ 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

Android version 3.31.0
Nextcloud version: 31.0.2

I was trying to download a file in my nextcloud instance and I could not figure out why it was failing to download it. It turns out to be caused by a ">" in the filename.

After I renamed the file to not include the ">" I could download it without any problem.
Note that the > in the file name is no problem for the nextcloud webinterface, only for the android app.

{
"app": "admin_audit",
"method": "GET",
"url": "/nextcloud/remote.php/dav/files/robert/Documents/Holidays/London%202025/6%20april%20-%20London%20-%3E%20Brussel.pdf",
"message": "File with id "773973" accessed: "/robert/files/Documents/Holidays/London 2025/6 april - London -> Brussel.pdf"",
"userAgent": "Mozilla/5.0 (Android) Nextcloud-android/3.31.0",
"version": "31.0.2.1",
}

I renamed the file from "6 april - London -> Brussel.pdf" to "6 april - London to Brussel.pdf" and could suddenly download the file without any problem.

Expected behaviour

That I can download files with > in the name or that the android client would tell me files with a > in the name are not supported

Actual behaviour

The app fails with a "failed to download file" message which isn't helpful at all.

Android version

14

Device brand and model

Samsung Galaxy S22

Stock or custom OS?

Stock

Nextcloud android app version

3.31.0

Nextcloud server version

31.0.2

Using a reverse proxy?

Yes

Android logs

No response

Server error logs

Additional information

No response

[alperozturk96]

Hello

Thank you for the report.

Could you try with this version: https://github.com/nextcloud/android/releases/tag/stable-3.31.1 ?

[PhilippGackstatter]

I have experienced the same problem on someone else's phone running 3.31.1. Removing the "->" fixes the problem, thanks for discovering the fix @rsevat!

[arkascha]

@alperozturk96 I tested with Version 3.31.1 with "mixed" results:

• The download of a file with a ">" in the filename resulted in an error claiming "Es ist ein Fehler beim Herunterladen der Datei aufgetreten" ("an error occurred while downloading the file").
• The download of a file without a ">" in the filename resulted in an error claiming that the device does not have an internet connection. Which is nonsense. An old bug, known for years, never fixed. So annoying. And so embarrassing.

[alperozturk96]

@arkascha

Thank you for the feedback.

I cannot create or rename a file with the ">" character on Android because this character causing IOException. Source

Example:

Screen.Recording.2025-04-28.at.10.54.08.mp4

I tried renaming the file through the web application and was able to do so. However, as you noted, I’m now unable to download the file due to the following error:

Error creating file /storage/emulated/0/Android/media/com.nextcloud.client/nextcloud/tmp/admin@10.0.2.2%3A55000/0003>.webp
java.io.IOException: Operation not permitted
at java.io.UnixFileSystem.createFileExclusively0(Native Method)
at java.io.UnixFileSystem.createFileExclusively(UnixFileSystem.java:368)
at java.io.File.createNewFile(File.java:1022)

The file cannot be downloaded because it can't be created due to not allowed characters in its name.

What can we do?

1. Warn the user about the file name.
2. Automatically replace forbidden characters with "_" (similar to the native Android Files app).

I need to discuss it with the team. @tobiasKaminsky

Update: We decided to just inform user via message for now. I will create PR for that.

[SamyDjemai]

I can also confirm that I'm not able to download files when their parent folder name contains >, I get a "an error occurred while downloading the file" notification. Removing it solves the problem immediately.