libnyanpasu/clash-nyanpasu · error · std::io::Error (Unsupported)

file symlinks are unsupported on this platform

Error message

file symlinks are unsupported on this platform

What it means

`create_file_symlink` in profile_file.rs provides symlink creation for unix and windows, but on any other target (cfg falls through) it returns an `Unsupported` io::Error stating file symlinks are unsupported. This is a compile-time platform gate: the code has no implementation for that platform.

Source

Thrown at backend/tauri/src/service/profile_file.rs:497

    #[cfg(not(windows))]
    {
        name == MATERIALIZATION_ROOT
    }
}

fn create_file_symlink(target: &Path, link: &Path) -> std::io::Result<()> {
    #[cfg(windows)]
    {
        std::os::windows::fs::symlink_file(target, link)
    }
    #[cfg(unix)]
    {
        std::os::unix::fs::symlink(target, link)
    }
    #[cfg(not(any(unix, windows)))]
    {
        let _ = (target, link);
        Err(std::io::Error::new(
            std::io::ErrorKind::Unsupported,
            "file symlinks are unsupported on this platform",
        ))
    }
}

fn hash_tagged(tag: &[u8], content: &[u8]) -> String {
    let mut digest = Sha256::new();
    digest.update(tag);
    digest.update([0]);
    digest.update(content);
    hex::encode(digest.finalize())
}

fn valid_operation_id(operation_id: &str) -> bool {
    operation_id.len() == 16
        && operation_id
            .bytes()

View on GitHub (pinned to f7dbce2997)

Solutions

1. Run only on supported platforms (unix/windows).
2. Add a platform-specific implementation or copy-based fallback in create_file_symlink for the new target.
3. Refactor callers to use a copy fallback when symlink support is absent.

Example fix

// before
Err(std::io::Error::new(ErrorKind::Unsupported, "file symlinks are unsupported on this platform"))
// after
std::fs::copy(target, link).map_err(|e| std::io::Error::new(e.kind(), format!("symlink unsupported; copy fallback failed: {e}")))

if !(cfg!(unix) || cfg!(windows)) {
    // use copy fallback instead of symlink
}

match create_file_symlink(target, link) {
    Err(e) if e.kind() == std::io::ErrorKind::Unsupported => std::fs::copy(target, link)?,
    other => other?,
}

When it happens

Trigger: Calling `create_ready_link` (directly or via journal/cleanup or atomic-write paths) on a platform that is neither unix nor windows (e.g. wasm target), reaching the fallback branch of `create_file_symlink`.

Common situations: Cross-compiling the service for an exotic target, running profile-linking logic in a wasm/web environment, or porting the profile service to a new OS without adding a symlink implementation.

Understand the failure class

Background: "unsupported platform" / "not supported on this platform" errors: what they mean and how to fix them — this error's family across 47 libraries.

Related errors

• runtime candidate directory is a symlink or reparse point: {
• profile directory is a symlink, reparse point, or non-direct
• materialization journal is not a regular file: {}
• private materialization artifact is not a regular file: {}
• staged file is not a regular file

AI-assisted analysis of libnyanpasu/clash-nyanpasu@f7dbce2997 (2026-09-08). Data as JSON: /api/errors/f4a0a6c235e79a72. Report an issue: GitHub.