What causes "{} " in pbakaus/impeccable?

Run `impeccable doctor` with no flags first to see valid usage output.

{}

Error message

{}

What it means

The doctor subcommand parses its args via parse_args; an unparseable argument (unknown flag or malformed option value) makes parse_args return Err(msg), and run prints that message (via the uncaught format) to stderr and exits 1 before doing any checks.

Source

Thrown at crates/context/src/doctor.rs:250

    }
    lines.join("\n")
}

pub fn run(args: &[String], io: &mut Io) -> i32 {
    let cwd = io.cwd.to_string_lossy().into_owned();
    let env = io.env.clone();
    let provider = crate::provider::detect(&env, &cwd);
    // The printed fix command spells the launcher when the launcher exported
    // IMPECCABLE_SELF, and the plain `impeccable` verb otherwise.
    let self_cmd = env
        .get("IMPECCABLE_SELF")
        .map(|v| v.trim().to_string())
        .filter(|v| !v.is_empty())
        .unwrap_or_else(|| "impeccable".to_string());
    let (flags, target) = match parse_args(args) {
        Ok(v) => v,
        Err(msg) => {
            io.err(&format!("{}\n", msg));
            return 1;
        }
    };
    if flags.help {
        io.out(&format!("{}\n", usage()));
        return 0;
    }
    let report = collect(&cwd, &target, &env, &provider.id);
    let fixes = if flags.fix { Some(apply_fixes(&report)) } else { None };
    if flags.json {
        let mut m = Map::new();
        m.insert("projectRoot".into(), Value::String(report.project_root.clone()));
        m.insert("repoRoot".into(), Value::String(report.ctx.repo_root.clone()));
        m.insert("isMonorepo".into(), Value::Bool(report.ctx.is_monorepo));
        m.insert("productPath".into(), opt_string(&report.ctx.product_path));
        m.insert("designPath".into(), opt_string(&report.ctx.design_path));
        m.insert("platform".into(), opt_string(&report.ctx.platform));
        m.insert("ruleRegistryAvailable".into(), Value::Bool(report.rule_registry_available));

View on GitHub (pinned to 2bc2879276)

Solutions

Run `impeccable doctor` with no flags first to see valid usage output.
Correct or remove the unsupported/malformed flag named in the printed message.
Supply the value a flag requires (e.g. `--target <path>`) instead of leaving it empty.
If migrating from an older version, check for renamed flags and use the current names.

Example fix

// before
impeccable doctor --traget ./app
// after
impeccable doctor --target ./app

Defensive patterns

Strategy: validation

Validate before calling

const KNOWN = new Set(['--target', '--help']);
for (const a of args) {
  if (a.startsWith('--') && !KNOWN.has(a)) throw new Error(`unsupported doctor flag: ${a}`);
}

Try / catch

try {
  runCapture('impeccable', ['doctor', ...args]);
} catch (e) {
  if (e.exitCode === 1 && /usage|--/.test(e.stderr)) {
    // fall back to flagless `impeccable doctor` for valid usage
  }
}

Prevention

Run flagless `impeccable doctor` first to learn the accepted flags.
Check flags against current docs after engine upgrades.
Never pass a flag without its required value.
Keep flag names lowercase-hyphenated as documented.

When it happens

Trigger: Running `impeccable doctor` with an unrecognized flag, a flag missing its value (`--target` with nothing after), or a positional/target that parse_args rejects.

Common situations: Typos like `--traget`, copying flags from another subcommand that doctor doesn't support, scripts interpolating empty flag values (`--target ''` patterns), or old flag names removed in a newer engine version.

Understand the failure class

Background: "unknown output mode", "invalid value for flag", "expects true/false": fixing invalid flag value errors in CLI tools — this error's family across 24 libraries.

Related errors

AI-assisted analysis of pbakaus/impeccable@2bc2879276 (2026-09-08). Data as JSON: /api/errors/78131cc8c063e4d9. Report an issue: GitHub.