jdx/mise · error

an exec entry with no command

Error message

an exec entry with no command

What it means

run_tool executes one of a tool's own executables as described by an argv list from the packslip resource commands. Before running, it takes the first element as the program via argv.split_first(); an empty argv has no command at all, so it bails. This is a malformed-manifest guard: an exec entry must name the command to run.

Source

Thrown at src/packslip.rs:1054

        .list_current_installed_versions(config)
        .into_iter()
        .find(|(b, _)| b.ba().short == name || b.tool_name() == name || b.id() == name);
    match by_name {
        Some(found) => Ok(found),
        None => bail!("{name} is not an active, installed tool or one of their executables"),
    }
}

/// Run one of the tool's own executables and return what it printed.
async fn run_tool(
    config: &Arc<Config>,
    backend: &Arc<dyn Backend>,
    tv: &ToolVersion,
    argv: &[String],
    env: &BTreeMap<String, String>,
) -> Result<String> {
    let Some((program, args)) = argv.split_first() else {
        bail!("an exec entry with no command");
    };
    let Some(path) = backend.which(config, tv, program).await? else {
        bail!("{} has no executable called {program}", tv.style());
    };
    run_resource_command(
        &path,
        args,
        env,
        &tv.install_path(),
        std::time::Duration::from_secs(5),
    )
    .await
}

/// Run vendor resource generation outside the user's project, without
/// input, under a deadline. Empty output is a failed source, never a cache hit.
async fn run_resource_command(
    path: &Path,

View on GitHub (pinned to afd2eddd3a)

Solutions

1. Fix the manifest/resource command so the exec entry's argv array has at least one element (the program).
2. If the argv comes from a template, verify the variable that supplies the command resolves to a non-empty value.
3. Validate the packslip resource commands before running (run the packslip check/validation flow).

Example fix

# before (packslip manifest)
exec = []

# after
exec = ["rg", "--version"]

if argv.is_empty() {
    return Err(anyhow!("resource command argv must contain at least a program"));
}

let Some((program, args)) = argv.split_first() else { return Err(anyhow!("an exec entry with no command")); };

match run_tool(config, &backend, &tv, &argv, &env).await {
    Err(e) if e.to_string().contains("no command") => eprintln!("Fix the exec entry: it must name a program"),
    Ok(out) => use(out),
    Err(e) => return Err(e),
}

When it happens

Trigger: A resource command's exec argv array is empty (e.g. `exec = []` or a computed/templated argv that expands to nothing), so split_first() returns None when run_tool is invoked from completion_script.

Common situations: A hand-edited or templated packslip manifest where the command string was left blank or a template variable failed to expand; array built programmatically from an empty config value.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• the packslip names an executable {:?}, which is not a plain
• packslip artifact must declare extensions.mise.plugin = vfox
• vfox plugin artifacts must not declare executables
• vfox plugin artifacts must not declare host requirements
• packslip: list_identity_prefix must be a non-empty string

AI-assisted analysis of jdx/mise@afd2eddd3a (2026-09-09). Data as JSON: /api/errors/1ac7eab4c12de95e. Report an issue: GitHub.