{"record":{"id":"fe71aab4650c719c","repo":"vercel/next.js","slug":"experimental-csschunking-graph-is-only-suppor","errorCode":null,"errorMessage":"`experimental.cssChunking: \"graph\"` is only supported with Turbopack. Please remove the option or run Next.js with Turbopack in ${configFileName}.","messagePattern":"`experimental\\.cssChunking: \"graph\"` is only supported with Turbopack\\. Please remove the option or run Next\\.js with Turbopack in (.+?)\\.","errorType":"exception","errorClass":"Error","httpStatus":null,"severity":"error","filePath":"packages/next/src/server/config.ts","lineNumber":571,"sourceCode":"  ) {\n    throw new Error(\n      `The experimental.allowDevelopmentBuild option requires NODE_ENV to be explicitly set to 'development'.`\n    )\n  }\n\n  // Validate sassOptions.functions is not used with Turbopack\n  if (\n    process.env.TURBOPACK &&\n    result.sassOptions &&\n    'functions' in result.sassOptions\n  ) {\n    throw new Error(\n      `The \"sassOptions.functions\" option is not supported when using Turbopack. ` +\n        `Custom Sass functions are only available with webpack. ` +\n        `Please remove the \"functions\" property from your sassOptions in ${configFileName}.`\n    )\n  }\n\n  // Validate experimental.cssChunking compatibility with the active bundler. Graph mode is\n  // Turbopack-only; strict mode and `false` (single-chunk-per-module) are webpack-only.\n  // Only validate during build/dev — `next start` doesn't pick a bundler and would otherwise\n  // see `process.env.TURBOPACK` unset and reject a valid `cssChunking: \"graph\"` config.\n  if (\n    phase !== PHASE_PRODUCTION_SERVER &&\n    phase !== PHASE_INFO &&\n    phase !== PHASE_TEST\n  ) {\n    if (result.experimental.durableUseCacheEntries && !process.env.TURBOPACK) {\n      throw new Error(\n        `\\`experimental.durableUseCacheEntries: true\\` is only supported with Turbopack. ` +\n          `Please remove the option or run Next.js with Turbopack in ${configFileName}.`\n      )\n    }\n\n    const cssChunkingValue = result.experimental.cssChunking\n    const cssChunkingMode = resolveCssChunkingMode(cssChunkingValue)","sourceCodeStart":553,"sourceCodeEnd":589,"githubUrl":"https://github.com/vercel/next.js/blob/34433fd12ee8074ea3f47af9f36255c7390d0301/packages/next/src/server/config.ts#L553-L589","documentation":"Config validation in assignDefaultsAndValidate: graph-mode CSS chunking is implemented only in Turbopack, so enabling experimental.cssChunking: \"graph\" while running the webpack (or rspack) bundler is rejected. The check only runs during build/dev, since next start does not select a bundler.","triggerScenarios":"experimental.cssChunking 'graph' mode is used without Turbopack.","commonSituations":"cssChunking: 'graph' in next.config while running with webpack.","solutions":["Remove experimental.cssChunking: \"graph\", or run with Turbopack (the default)."],"exampleFix":null,"handlingStrategy":"validation","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"34433fd12ee8074ea3f47af9f36255c7390d0301","analyzedAt":"2026-08-19T02:10:13.922Z","contentChangedAt":"2026-08-19T02:10:13.922Z","schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}