cross-rs/cross · error

failed to get rustup version

Error message

failed to get rustup version

What it means

`version()` runs `rustup --version`, parses the first output line, and expects a semver token as the second whitespace-separated field. If the line is missing or has no version token, it bails with `failed to get rustup version`. This check exists to verify rustup is usable before operations like installing toolchains.

Solutions

1. Install/update rustup: `rustup --version` manually must print e.g. `rustup 1.26.0 (...)`; if not, reinstall via rustup.rs.
2. Ensure `rustup` is on PATH for the process (check PATH in CI/container environments).
3. Update rustup (`rustup self update`) if the version line format differs from expectations.
4. If rustup is present but crashing, repair the installation (`rustup toolchain install stable` or reinstall) — the failure usually precedes version parsing.

Example fix

// before
let v = rustup::version(msg_info)?; // bails if no version token
// after
let v = match rustup::version(msg_info) {
    Ok(v) => v,
    Err(e) => anyhow::bail!("rustup is missing or broken ({}). Install from https://rustup.rs", e),
};

fn rustup_ok() -> bool {
    std::process::Command::new("rustup").arg("--version")
        .output().map(|o| o.status.success() && !o.stdout.is_empty()).unwrap_or(false)
}

match rustup::version(msg_info) {
    Ok(v) => v,
    Err(e) => return Err(anyhow!("rustup missing or broken: {e}; install via https://rustup.rs")),
}

When it happens

Trigger: `rustup --version` output contains no second field — e.g. rustup missing/aborting with only an error line, a wrapper script emitting custom text, or stderr/stdout capture returning empty output.

Common situations: rustup not installed or not on PATH (only an error line captured); extremely old or patched rustup builds with different `--version` output; broken rustup install where the binary exists but fails at startup (missing libgcc, corrupted toolchain); running inside images that shim rustup.

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AI-assisted analysis of cross-rs/cross@8c1a8aa4b6 (2026-09-13). Data as JSON: /api/errors/f1a771bebf85d0b9. Report an issue: GitHub.

Appendix: source

Thrown at src/rustup.rs:177

        installed,
        not_installed,
    })
}

fn version(msg_info: &mut MessageInfo) -> Result<Version> {
    let out = rustup_command(msg_info, false)
        .arg("--version")
        .run_and_get_stdout(msg_info)?;

    match out
        .lines()
        .next()
        .and_then(|line| line.split_whitespace().nth(1))
    {
        Some(version) => {
            semver::Version::parse(version).wrap_err_with(|| "failed to parse rustup version")
        }
        None => eyre::bail!("failed to get rustup version"),
    }
}

pub fn install_toolchain(toolchain: &QualifiedToolchain, msg_info: &mut MessageInfo) -> Result<()> {
    let mut command = rustup_command(msg_info, false);
    let toolchain = toolchain.to_string();
    command.args(["toolchain", "add", &toolchain, "--profile", "minimal"]);
    if version(msg_info)? >= semver::Version::new(1, 25, 0) {
        command.arg("--force-non-host");
    }
    command
        .run(msg_info, false)
        .wrap_err_with(|| format!("couldn't install toolchain `{toolchain}`"))
}

pub fn install(
    target: &Target,
    toolchain: &QualifiedToolchain,

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