badges/shields · error · InvalidParameter

Invalid flags, must be one of: ${VALID_FLAGS}

Error message

Invalid flags, must be one of: ${VALID_FLAGS}

What it means

This InvalidParameter is thrown by the dynamic-regex (dynamic/json-regex style) service's validate step when the flags query parameter contains any character not present in VALID_FLAGS (the single-character regex modifiers allowed, e.g. 'i' and 'g'). Flags must be a string whose every character is an accepted regex flag. The check runs before any regex is compiled.

Source

Thrown at services/dynamic/dynamic-regex.service.js:73

            required: false,
            example: '$<amount>/$1',
          },
          {
            name: 'flags',
            description:
              'Flags to be used when creating the regex: `i` = case-insensitive, `m` = multi-line mode, `s` = dot matches linebreaks. None by default.',
            required: false,
            example: VALID_FLAGS,
          },
        ),
      },
    },
  }
  static defaultBadgeData = { label: 'match' }

  static validate(flags) {
    if (flags?.split('')?.some(c => VALID_FLAGS.indexOf(c) === -1)) {
      throw new InvalidParameter({
        prettyMessage: `Invalid flags, must be one of: ${VALID_FLAGS}`,
      })
    }
  }

  static transform(buffer, search, replace, flags) {
    // build re2 regex
    let re2
    try {
      re2 = new RE2(search, flags)
    } catch (error) {
      if (error instanceof SyntaxError) {
        throw new InvalidParameter({
          prettyMessage: `Invalid re2 regex: ${error.message}`,
        })
      }
      throw error
    }

View on GitHub (pinned to 766fd8bc89)

Solutions

1. Restrict the flags parameter to characters listed in VALID_FLAGS (e.g. i, g).
2. Remove unsupported modifiers from the URL; emulate multiline behavior within the regex body if needed.
3. URL-encode the flags value to avoid stray characters/space corruption.

Example fix

// before
/badge/dynamic/json.svg?url=...&query=...&search=version&replace=$1&flags=igm
// after
/badge/dynamic/json.svg?url=...&query=...&search=version&replace=$1&flags=gi

const VALID_FLAGS = 'ig';
function validateFlags(flags) {
  if (flags && [...flags].some(c => !VALID_FLAGS.includes(c))) {
    throw new Error(`Invalid flags, must be one of: ${VALID_FLAGS}`);
  }
}
validateFlags('gi'); // ok before calling the service

function hasValidFlags(flags) {
  return flags === undefined || [...flags].every(c => 'ig'.includes(c));
}

When it happens

Trigger: Passing flags such as flags=m (unsupported modifier), flags=igm (contains unsupported 'm'), flags with spaces, or multi-letter flags like flags=giu where 'u' is not in VALID_FLAGS.

Common situations: Copying flags from PCRE/JS docs that include unsupported modifiers (m, s, u, x); combining flags as words ('global') instead of single letters; typos in badge URLs.

Related errors

• Invalid re2 regex: ${error.message}
• Field `idSuffix` must contain only numbers, letters, -, and
• invalid api key
• monitor API key is unvalid
• must use a monitor-specific api key

AI-assisted analysis of badges/shields@766fd8bc89 (2026-08-30). Data as JSON: /api/errors/85a558318e52cf17. Report an issue: GitHub.