astrid-runtime/astrid · error

--output requires a path

Error message

--output requires a path

What it means

CLI argument parse error in `parse_options`: `--output` was given but the next argument is missing. The flag requires a following filesystem path where the compact JSON report is written instead of stdout.

Source

Thrown at crates/astrid-storage-chunker-evidence/src/main.rs:176

                version_chain_specs.push(parse_path_specification("--version-chain", args.next())?);
            },
            "--git-history" => {
                git_history_specs.push(parse_git_specification(args.next())?);
            },
            "--no-synthetic" => include_synthetic = false,
            "--sketch-only" => sketch_only = true,
            "--target-kib" => {
                let target = args
                    .next()
                    .ok_or_else(|| anyhow::anyhow!("--target-kib requires an integer"))?
                    .parse::<u32>()
                    .context("parse --target-kib")?;
                targets_kib.push(target);
            },
            "--output" => {
                let path = args
                    .next()
                    .ok_or_else(|| anyhow::anyhow!("--output requires a path"))?;
                output = Some(PathBuf::from(path));
            },
            "-h" | "--help" => {
                print_help();
                std::process::exit(0);
            },
            unknown => bail!("unknown argument {unknown:?}; use --help"),
        }
    }
    if targets_kib.is_empty() {
        targets_kib.push(64);
    }
    targets_kib.sort_unstable();
    targets_kib.dedup();
    Ok(Options {
        corpus_specs,
        version_chain_specs,
        git_history_specs,

View on GitHub (pinned to affd8760f4)

Solutions

1. Supply the path: `--output report.json`.
2. In scripts, verify the output variable is non-empty before invoking the binary.
3. Check `--help` for the `--output PATH` syntax.

Example fix

// before
mybin --corpus c=dir --output
// after
mybin --corpus c=dir --output out/report.json

fn output_path_provided(args: &[String]) -> bool {
    args.iter().position(|a| a == "--output")
        .map(|i| args.get(i + 1).map_or(false, |v| !v.starts_with("--")))
        .unwrap_or(false)
}

let path = std::env::args().skip(1)
    .skip_while(|a| a != "--output").nth(1);
assert!(path.is_some(), "--output requires a path");

When it happens

Trigger: Running the binary as `... --output` with no path after it — the flag ends the argument list or is followed by another flag, so `args.next()` returns `None`.

Common situations: Truncated command from a script; empty variable interpolated as the output path; mistaking `--output` for a boolean flag and passing only it.

Understand the failure class

Background: "no subcommand specified" and "... is required": CLI errors when a required argument is missing — this error's family across 13 libraries.

Related errors

• unknown argument {unknown:?}; use --help
• --var must be KEY=VALUE (got {item:?})
• --target-kib requires an integer
• --git-history requires NAME=REPO::RELATIVE_PATH
• {flag} requires NAME=PATH

AI-assisted analysis of astrid-runtime/astrid@affd8760f4 (2026-09-09). Data as JSON: /api/errors/1527677e717180f0. Report an issue: GitHub.