{"record":{"id":"e7145574caf24319","repo":"vercel/next.js","slug":"mangling-is-disabled-note-this-may-affect-perfor-e71455","errorCode":null,"errorMessage":"Mangling is disabled. Note: This may affect performance and should only be used for debugging purposes.","messagePattern":"Mangling is disabled\\. Note: This may affect performance and should only be used for debugging purposes\\.","errorType":"console","errorClass":null,"httpStatus":null,"severity":"error","filePath":"packages/next/src/cli/next-build.ts","lineNumber":74,"sourceCode":"    experimentalUploadTrace,\n    debugBuildPaths,\n  } = options\n\n  let traceUploadUrl: string | undefined\n  if (experimentalUploadTrace && !process.env.NEXT_TRACE_UPLOAD_DISABLED) {\n    traceUploadUrl = experimentalUploadTrace\n  }\n\n  const bundler = parseBundlerArgs(options)\n\n  if (experimentalAnalyze && bundler !== Bundler.Turbopack) {\n    printAndExit(\n      '--experimental-analyze is only compatible with the Turbopack bundler.'\n    )\n  }\n\n  if (!mangling) {\n    warn(\n      `Mangling is disabled. ${italic('Note: This may affect performance and should only be used for debugging purposes.')}`\n    )\n  }\n\n  if (profile) {\n    warn(\n      `Profiling is enabled. ${italic('Note: This may affect performance.')}`\n    )\n  }\n\n  if (debugPrerender) {\n    warn(\n      `Prerendering is running in debug mode with NODE_ENV='development'. ${italic(\n        'This will affect performance and should not be used for production.'\n      )}`\n    )\n  }\n","sourceCodeStart":56,"sourceCodeEnd":92,"githubUrl":"https://github.com/vercel/next.js/blob/0eb377541648e63402a47b38fee00a8d0ce8f8f1/packages/next/src/cli/next-build.ts#L56-L92","documentation":"Informational warning printed by next-build at startup when identifier mangling is disabled (the default unless --turbopack-mangle or equivalent is used, or when explicitly turned off). It means symbols in the production bundle keep their original names, which increases bundle size and can reduce runtime performance; it is intended only for debugging production builds with readable stack traces.","triggerScenarios":"Thrown at packages/next/src/cli/next-build.ts:74 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Remove the disable-mangling flag for normal builds; keep it only for debugging sessions."],"exampleFix":null,"handlingStrategy":"fallback","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"0eb377541648e63402a47b38fee00a8d0ce8f8f1","analyzedAt":"2026-08-19T02:10:13.922Z","contentChangedAt":"2026-08-19T02:10:13.922Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}