jackwener/OpenCLI · error · ArgumentError

rubygems ${label} cannot be empty

Error message

rubygems ${label} cannot be empty

What it means

requireString in clis/rubygems/utils.js coerces its argument to a trimmed string and throws ArgumentError('rubygems ${label} cannot be empty') when the result is empty. It is the guard used for required string arguments such as the search query, so the library fails fast instead of issuing a doomed API call.

Source

Thrown at clis/rubygems/utils.js:17

// Shared helpers for the RubyGems.org adapters.
//
// Hits the public, unauthenticated `rubygems.org/api/v1` REST endpoints. No
// auth required for read-only metadata; the API is friendly to anonymous CLI
// traffic. Gem names follow the RubyGems convention: lowercase ASCII +
// `-_.`, 1-100 chars, must start with a letter or digit.
import { ArgumentError, CommandExecutionError, EmptyResultError } from '@jackwener/opencli/errors';

export const GEMS_BASE = 'https://rubygems.org/api/v1';
const UA = 'opencli-rubygems-adapter (+https://github.com/jackwener/opencli)';

// RubyGems gem name pattern (mirrors the rubygems-server validation).
const GEM_NAME = /^[A-Za-z0-9][A-Za-z0-9._-]*$/;

export function requireString(value, label) {
    const s = String(value ?? '').trim();
    if (!s) throw new ArgumentError(`rubygems ${label} cannot be empty`);
    return s;
}

export function requireBoundedInt(value, defaultValue, maxValue, label = 'limit') {
    const raw = value ?? defaultValue;
    const n = typeof raw === 'number' ? raw : Number(raw);
    if (!Number.isInteger(n) || n <= 0) {
        throw new ArgumentError(`rubygems ${label} must be a positive integer`);
    }
    if (n > maxValue) {
        throw new ArgumentError(`rubygems ${label} must be <= ${maxValue}`);
    }
    return n;
}

export function requireGemName(value) {
    const s = String(value ?? '').trim();
    if (!s) {

View on GitHub (pinned to 49907e53dc)

Solutions

1. Supply a non-empty value for the flagged argument, e.g. `opencli rubygems search --query rails`.
2. Check the variable feeding the argument: `echo "$QUERY"` to confirm it is not empty before invoking.
3. In calling code, default or prompt for the value: args.query ||= (await prompt('query:')).

Example fix

// before
await search({ query: '' }); // throws

// after
const query = (process.argv[2] || '').trim();
if (!query) throw new Error('usage: rubygems search <query>');
await search({ query });

function requireQuery(q) {
  const s = String(q ?? '').trim();
  if (!s) throw new Error('query must be a non-empty string');
  return s;
}

function isNonEmptyString(v) {
  return typeof v === 'string' && v.trim().length > 0;
}

try {
  await search({ query: args.query });
} catch (e) {
  if (e instanceof ArgumentError && /cannot be empty/.test(e.message)) {
    console.error('Provide a search term, e.g. --query rails');
    process.exitCode = 2;
  } else throw e;
}

When it happens

Trigger: requireString(value, label) receives null, undefined, an empty string, or whitespace-only input; e.g. search({ query: '' }) or search({}) where query is undefined (label 'query').

Common situations: Forgetting to pass the query flag on the CLI (`opencli rubygems search` with no argument); a shell variable holding the query being unset/empty; passing an empty array/object that stringifies to ''.

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

• rubygems gem name is required (e.g. "rails", "sidekiq")
• rubygems gem "${value}" is not a valid gem name
• --limit must be a positive integer, got ${JSON.stringify(kwa
• `endoflife ${label} must be <= ${maxValue}`
• facebook search --limit must be an integer between 1 and ${M

AI-assisted analysis of jackwener/OpenCLI@49907e53dc (2026-08-29). Data as JSON: /api/errors/322796ebab97a72a. Report an issue: GitHub.