{"record":{"id":"e1dbe5931e0c372d","repo":"vercel/next.js","slug":"the-key-option-has-been-modified-custommes","errorCode":null,"errorMessage":"The \"${key}\" option has been modified. ${customMessage ? customMessage + '. ' : ''}It should be removed from your ${configFileName}.","messagePattern":"The \"(.+?)\" option has been modified\\. (.+?)It should be removed from your (.+?)\\.","errorType":"console","errorClass":null,"httpStatus":null,"severity":"error","filePath":"packages/next/src/server/config.ts","lineNumber":335,"sourceCode":"  key: string,\n  defaultValue: any,\n  customMessage: string,\n  configFileName: string,\n  silent: boolean\n) {\n  const segs = key.split('.')\n  let current = config\n\n  while (segs.length >= 1) {\n    const seg = segs.shift()!\n    if (!(seg in current)) {\n      return\n    }\n    current = (current as any)[seg]\n  }\n\n  if (!silent && current !== defaultValue) {\n    Log.warn(\n      `The \"${key}\" option has been modified. ${customMessage ? customMessage + '. ' : ''}It should be removed from your ${configFileName}.`\n    )\n  }\n}\n\n/**\n * Assigns defaults to the user config and validates the config.\n *\n * @param dir - The directory of the project.\n * @param userConfig - The user config.\n * @param silent - Whether to suppress warnings.\n * @returns The complete config.\n */\nfunction assignDefaultsAndValidate(\n  dir: string,\n  userConfig: NextConfig & { configFileName: string },\n  silent: boolean,\n  phase: PHASE_TYPE","sourceCodeStart":317,"sourceCodeEnd":353,"githubUrl":"https://github.com/vercel/next.js/blob/258b1c1bc05f7099816b88f70b7b3422b24a4b8d/packages/next/src/server/config.ts#L317-L353","documentation":"Warning from warnCustomizedOption during config load: it walks the dotted key path through the user's config and compares the found value against the known default. A value that differs from the default means the user customized an option Next.js no longer reads (its behavior is fixed now), so the warning — with an optional custom explanation — asks for its removal from the config file.","triggerScenarios":"Thrown at packages/next/src/server/config.ts:302 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Remove the modified/deprecated option from your next.config file."],"exampleFix":null,"handlingStrategy":"validation","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"258b1c1bc05f7099816b88f70b7b3422b24a4b8d","analyzedAt":"2026-08-19T02:10:13.922Z","contentChangedAt":"2026-08-19T02:10:13.922Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}