Invalid URL rewrite regex pattern "${rule.match}": ${error i

Error message

Invalid URL rewrite regex pattern "${rule.match}": ${error instanceof Error ? error.message : String(error)}

What it means

validateRuleOrThrow compiles `new RegExp(rule.match, buildFlags(rule))` to validate the rewrite pattern. If the pattern is syntactically invalid (unbalanced groups, bad quantifiers, invalid escape sequences), it logs and rethrows a detailed message including the pattern and the underlying RegExp error. This prevents a bad regex from blowing up later mid-rewrite of image URLs.

Source

Thrown at src/main/events/rpc/routes/albumToolbox/builtIn/changeURL.ts:48

      ignoreCase: raw.ignoreCase === true
    }
  }).filter(rule => rule.match.length > 0)
}

function buildFlags (rule: Pick<IUrlRewriteRule, 'global' | 'ignoreCase'>): string {
  return `${rule.global ? 'g' : ''}${rule.ignoreCase ? 'i' : ''}`
}

function validateRuleOrThrow (rule: IUrlRewriteRule) {
  if (!rule.match.trim() || !rule.replace.trim()) {
    throw new Error(T('ALBUM_URL_REWRITE_TEMP_RULE_REQUIRED'))
  }
  try {
    new RegExp(rule.match, buildFlags(rule))
  } catch (error) {
    const message = `Invalid URL rewrite regex pattern "${rule.match}": ${error instanceof Error ? error.message : String(error)}`
    logger.error(message)
    throw new Error(message)
  }
}

function applyFirstMatchRewrite (ctx: IPicGo, imgItem: ImgInfo, rules: IUrlRewriteRule[]): ImgInfo {
  const imgInfo = {
    imgUrl: imgItem.imgUrl,
    originImgUrl: imgItem.originImgUrl
  }
  PicGoUtils.applyUrlRewriteToImgInfo(imgInfo, rules, {
    log: {
      error: (...args: Parameters<IPicGo['log']['error']>) => ctx.log.error(...args),
      warn: () => ctx.log.warn(T('ALBUM_URL_REWRITE_EMPTY_RESULT_WARN'))
    }
  })
  if (imgInfo.imgUrl === '') return imgItem
  return imgInfo
}

View on GitHub (pinned to 07ec7068a5)

Solutions

Fix the `match` pattern so `new RegExp(pattern, flags)` compiles — escape special characters like [ ] ( ) { } * + ? \\ ^ $ |
Test the pattern in the browser console with new RegExp before submitting
Remove unsupported constructs (named groups/lookbehind on old Electron builds) or upgrade the runtime
If the pattern comes from user input, validate with try { new RegExp(input) } catch at the form level and show inline feedback

Example fix

// before
{ match: 'https://old.com/(img', replace: '$1' } // Invalid: unclosed group
// after
{ match: 'https://old\\.com/(img)', replace: '$1' }

Defensive patterns

Strategy: validation

Validate before calling

function isCompilableRegex(pattern, flags) {
  try { new RegExp(pattern, flags); return true } catch { return false }
}
if (!isCompilableRegex(rule.match, buildFlags(rule))) throw new Error('invalid regex')

Try / catch

try {
  await changeURL(rule)
} catch (e) {
  if (e.message.startsWith('Invalid URL rewrite regex pattern')) {
    showInlineRegexError(e.message)
  } else throw e
}

Prevention

Compile the pattern with new RegExp in the form before saving
Escape regex metacharacters when treating user text literally
Test patterns against sample image URLs before applying to the album
Avoid regex dialects not supported by JS (e.g. some PCRE constructs)

When it happens

Trigger: Submitting an IUrlRewriteRule whose `match` is not a valid JavaScript RegExp — e.g. 'img[' , 'a{2,1}', trailing backslash, or invalid unicode escapes — through the changeURL RPC route.

Common situations: Hand-typing regexes in the UI with unescaped special chars; copying PCRE/ripgrep syntax not supported by JS RegExp (e.g. lookbehind on old engines, \\p removed variants); pasting glob patterns expecting regex semantics.

Related errors

AI-assisted analysis of Molunerfinn/PicGo@07ec7068a5 (2026-08-30). Data as JSON: /api/errors/47e006c5432cc07a. Report an issue: GitHub.