Invalid next.config.js options detected warning

[fnick851]

terminal:

npm run lint

> react-three-next@2.0.0 lint
> next lint --fix --dir app

- warn Invalid next.config.js options detected: 
- warn     The value at .experimental has an unexpected property, reactRoot, which is not in the list of allowed properties (appDocumentPreloading, adjustFontFallbacks, adjustFontFallbacksWithSizeAdjust, allowedRevalidateHeaderKeys, amp, clientRouterFilter, clientRouterFilterRedirects, clientRouterFilterAllowedRate, cpus, memoryBasedWorkersCount, craCompat, disableOptimizedLoading, disablePostcssPresetEnv, esmExternals, appDir, serverActions, extensionAlias, externalDir, externalMiddlewareRewritesResolve, fallbackNodePolyfills, fetchCacheKeyPrefix, forceSwcTransforms, fullySpecified, gzipSize, incrementalCacheHandlerPath, isrFlushToDisk, isrMemoryCacheSize, largePageDataBytes, legacyBrowsers, manualClientBasePath, middlewarePrefetch, newNextLinkBehavior, nextScriptWorkers, optimizeCss, optimisticClientCache, outputFileTracingRoot, outputFileTracingExcludes, outputFileTracingIgnores, outputFileTracingIncludes, pageEnv, proxyTimeout, serverComponentsExternalPackages, scrollRestoration, sharedPool, sri, strictNextHead, swcFileReading, swcMinify, swcPlugins, swcTraceProfiling, urlImports, workerThreads, webVitalsAttribution, mdxRs, typedRoutes, webpackBuildWorker, turbo, instrumentationHook, turbotrace, logging).
- warn See more info here: https://nextjs.org/docs/messages/invalid-next-config
- warn You have enabled experimental feature (reactRoot) in next.config.js.
- warn Experimental features are not covered by semver, and may cause unexpected or broken application behavior. Use at your own risk.

package.json:

{
  "name": "react-three-next",
  "version": "2.0.0",
  "authors": [
    "Renaud ROHLINGER <https://twitter.com/onirenaud>"
  ],
  "license": "MIT",
  "private": true,
  "engines": {
    "node": ">=14"
  },
  "scripts": {
    "lint": "next lint --fix --dir app",
    "dev": "next dev",
    "build": "next build",
    "analyze": "ANALYZE=true next build",
    "start": "next start"
  },
  "dependencies": {
    "@ducanh2912/next-pwa": "^8.2.0",
    "@react-three/drei": "^9.65.3",
    "@react-three/fiber": "^8.12.0",
    "glsl-random": "^0.0.5",
    "next": "^13.4.2",
    "react": "^18.2.0",
    "react-dom": "^18.2.0",
    "three": "^0.151.3",
    "three-stdlib": "^2.21.8",
    "tunnel-rat": "^0.1.2"
  },
  "devDependencies": {
    "@next/bundle-analyzer": "^13.3.0",
    "autoprefixer": "^10.4.14",
    "eslint": "^8.38.0",
    "eslint-config-next": "^13.3.0",
    "eslint-config-prettier": "^8.8.0",
    "eslint-plugin-tailwindcss": "^3.11.0",
    "file-loader": "^6.2.0",
    "glslify": "^7.1.1",
    "glslify-loader": "^2.0.0",
    "postcss": "^8.4.21",
    "prettier": "^2.8.7",
    "raw-loader": "^4.0.2",
    "tailwindcss": "^3.3.1",
    "url-loader": "^4.1.1"
  }
}

Although it is just a warning, I am curious about what causes this? And is there any fix? Thanks.

[fnick851]

I think I can just remove the reactRoot: 'concurrent', line. It is probably an old config option that is no longer supported.

[Raspber]

yes, remove it and it should go away.

[Iceteatree]

Have removed it in my local, seems to do the trick. +1 for removal. @fnick851 should open a PR :)

[CodyJasonBennett]

FWIW that option no longer has an effect with React 18 -- roots are effectively concurrent by default. A PR would be more than welcome here.