What causes "Missing value for --locale" in affaan-m/ECC?

Supply a supported locale value immediately after --locale, e.g. `--locale zh-CN`.

affaan-m/ECC · error · Error

Missing value for --locale

Error message

Missing value for --locale

What it means

Thrown by the install CLI argument parser when --locale is the last token on the command line or is immediately followed by another flag (a token starting with --). The parser expects --locale to consume the next argv slot as the locale value.

Source

Thrown at scripts/lib/install/request.js:67

    } else if (arg === '--with') {
      const componentId = args[index + 1] || '';
      if (componentId.trim()) {
        parsed.includeComponentIds.push(componentId.trim());
      }
      index += 1;
    } else if (arg === '--skill' || arg === '--skills') {
      parsed.includeComponentIds.push(...normalizeSkillComponentIds(args[index + 1] || ''));
      index += 1;
    } else if (arg === '--without') {
      const componentId = args[index + 1] || '';
      if (componentId.trim()) {
        parsed.excludeComponentIds.push(componentId.trim());
      }
      index += 1;
    } else if (arg === '--locale') {
      const locale = args[index + 1] || '';
      if (!locale || locale.startsWith('--')) {
        throw new Error('Missing value for --locale');
      }
      parsed.locale = locale;
      index += 1;
    } else if (arg === '--dry-run') {
      parsed.dryRun = true;
    } else if (arg === '--json') {
      parsed.json = true;
    } else if (arg === '--help' || arg === '-h') {
      parsed.help = true;
    } else if (arg.startsWith('--')) {
      throw new Error(`Unknown argument: ${arg}`);
    } else {
      parsed.languages.push(arg);
    }
  }

  return parsed;
}

View on GitHub (pinned to 01e15490f0)

Solutions

Supply a supported locale value immediately after --locale, e.g. `--locale zh-CN`.
If locale was unintended, remove the --locale flag entirely.
Quote the value if it contains special characters (none of the supported locales do, so this usually indicates a different bug).

Example fix

# before
npx ecc install --locale
# after
npx ecc install --locale zh-CN --target claude

Defensive patterns

Strategy: validation

Validate before calling

function hasLocaleValue(argv) {
  const i = argv.indexOf('--locale');
  if (i === -1) return true;
  const next = argv[i + 1];
  return Boolean(next) && !next.startsWith('--');
}

Try / catch

try {
  const request = normalizeInstallRequest(parseInstallArgs(argv));
} catch (e) {
  if (/Missing value for --locale/.test(e.message)) {
    console.error('Usage: ecc install --locale <locale> ...');
    process.exit(2);
  }
  throw e;
}

Prevention

Validate flag/value pairs before invoking the parser when building commands programmatically.
Prefer config-file locale over the CLI flag to avoid shell-quoting pitfalls.
Print --help output when the parser rejects arguments so users can self-correct.

When it happens

Trigger: Invoking `npx ecc install --locale` with no following argument, or `--locale --target claude` where the next token is itself a flag.

Common situations: Typos; copy-pasting a partial command; shell-quoting bugs that drop the locale value; scripts that conditionally append --locale but forget the value.

Related errors

AI-assisted analysis of affaan-m/ECC@01e15490f0 (2026-08-13). Data as JSON: /api/errors/373e73801b6ccf70. Report an issue: GitHub.