libnyanpasu/clash-nyanpasu · error · anyhow::Error

failed to get core version

Error message

failed to get core version

What it means

resolve_core_version spawns the selected clash core sidecar binary with -v/-V and captures its output. If the process exits with a non-zero status, the version cannot be trusted, so this error is raised. It indicates the core binary is present (the command ran) but reported failure.

Source

Thrown at backend/tauri/src/utils/resolve.rs:795

    };
    app_handle.get_webview_window(window.label()).is_some()
}

/// resolve core version
// TODO: use enum instead
pub async fn resolve_core_version(app_handle: &AppHandle, core_type: &ClashCore) -> Result<String> {
    let shell = app_handle.shell();
    let core = core_type.clone().to_string();
    log::debug!(target: "app", "check config in `{core}`");
    let cmd = match core_type {
        ClashCore::ClashPremium | ClashCore::Mihomo | ClashCore::MihomoAlpha | ClashCore::Meow => {
            shell.sidecar(core)?.args(["-v"])
        }
        ClashCore::ClashRs | ClashCore::ClashRsAlpha => shell.sidecar(core)?.args(["-V"]),
    };
    let out = cmd.output().await?;
    if !out.status.success() {
        return Err(anyhow::anyhow!("failed to get core version"));
    }
    let out = String::from_utf8_lossy(&out.stdout);
    log::trace!(target: "app", "get core version: {out:?}");
    let out = out.trim().split(' ').collect::<Vec<&str>>();
    for item in out {
        log::debug!(target: "app", "check item: {item}");
        if item.starts_with('v')
            || item.starts_with('n')
            || item.starts_with("alpha")
            || Version::parse(item).is_ok()
        {
            match core_type {
                ClashCore::ClashRs => return Ok(format!("v{}", item)),
                _ => return Ok(item.to_string()),
            }
        }
    }
    Err(anyhow::anyhow!("failed to get core version"))

View on GitHub (pinned to f7dbce2997)

Solutions

1. Log/print out.stderr to see the core's own failure message
2. Run the core binary manually with -v (or -V for clash-rs) to reproduce and read the error
3. Re-download or reinstall the core sidecar (pnpm prepare:check) to fix a corrupt/mismatched binary
4. If a newer core dropped the -v flag, update the flag mapping in the match on ClashCore

Example fix

// before
if !out.status.success() {
    return Err(anyhow::anyhow!("failed to get core version"));
}
// after: include stderr for diagnosis
if !out.status.success() {
    return Err(anyhow::anyhow!(
        "failed to get core version (status {:?}): {}",
        out.status,
        String::from_utf8_lossy(&out.stderr)
    ));
}

let ok = tokio::process::Command::new(core_path)
    .arg("-v")
    .output().await
    .map(|o| o.status.success())
    .unwrap_or(false);
if !ok { log::warn!("core binary cannot report version"); }

match resolve_core_version(core).await {
    Ok(v) => log::info!("core version: {v}"),
    Err(e) => {
        log::error!("core version check failed: {e:#}");
        // fall back to assumed version or prompt reinstall
    }
}

When it happens

Trigger: cmd.output() succeeded but out.status.success() is false — the core binary rejects the -v flag, fails to initialize, or crashes at startup.

Common situations: Core version changed and no longer supports -v/-V; broken/incompatible build of mihomo or clash-rs; missing dynamic libraries or runtime deps causing early exit; sidecar mismatched with the platform.

Understand the failure class

Background: 'Something went wrong' / 'Request failed (500)' / 'HTTP error! status: 404' — what failed HTTP requests actually mean and how to find the real cause — this error's family across 28 libraries.

Related errors

• child process failed: {:?}, err: {}
• {} not found
• {operation} failed with status {status}
• {stderr}
• failed to copy core: {status}

AI-assisted analysis of libnyanpasu/clash-nyanpasu@f7dbce2997 (2026-09-08). Data as JSON: /api/errors/e44504f4ac36103b. Report an issue: GitHub.