{"record":{"id":"4653429700ba724f","repo":"vercel/next.js","slug":"the-cli-flag-cliserverfastrefresh-false","errorCode":null,"errorMessage":"The CLI flag \"${cliServerFastRefresh === false ? '--no-server-fast-refresh' : '--server-fast-refresh'}\" conflicts with \"experimental.turbopackServerFastRefresh: ${configServerFastRefresh}\" in your Next.js config. The CLI flag will take precedence.","messagePattern":"The CLI flag \"(.+?)\" conflicts with \"experimental\\.turbopackServerFastRefresh: (.+?)\" in your Next\\.js config\\. The CLI flag will take precedence\\.","errorType":"console","errorClass":null,"httpStatus":null,"severity":"error","filePath":"packages/next/src/server/lib/router-server.ts","lineNumber":232,"sourceCode":"    const setupDevBundlerSpan = opts.startServerSpan\n      ? opts.startServerSpan.traceChild('setup-dev-bundler')\n      : trace('setup-dev-bundler')\n\n    // In development, it's always the complete config.\n    let developmentConfig = config as NextConfigComplete\n\n    // Resolve the effective serverFastRefresh value.\n    // Both default to enabled (true). CLI takes precedence over config.\n    const cliServerFastRefresh = opts.serverFastRefresh\n    const configServerFastRefresh =\n      developmentConfig.experimental?.turbopackServerFastRefresh\n    let effectiveServerFastRefresh: boolean | undefined\n    if (\n      cliServerFastRefresh !== undefined &&\n      configServerFastRefresh !== undefined &&\n      cliServerFastRefresh !== configServerFastRefresh\n    ) {\n      Log.warn(\n        `The CLI flag \"${cliServerFastRefresh === false ? '--no-server-fast-refresh' : '--server-fast-refresh'}\" conflicts with \"experimental.turbopackServerFastRefresh: ${configServerFastRefresh}\" in your Next.js config. The CLI flag will take precedence.`\n      )\n      effectiveServerFastRefresh = cliServerFastRefresh\n    } else {\n      // Default to true when neither CLI nor config specifies a value.\n      effectiveServerFastRefresh =\n        cliServerFastRefresh ?? configServerFastRefresh ?? true\n    }\n\n    let developmentBundler = await setupDevBundlerSpan.traceAsyncFn(() =>\n      setupDevBundler({\n        // Passed here but the initialization of this object happens below, doing the initialization before the setupDev call breaks.\n        renderServer,\n        appDir,\n        pagesDir,\n        telemetry,\n        fsChecker,\n        dir: opts.dir,","sourceCodeStart":214,"sourceCodeEnd":250,"githubUrl":"https://github.com/vercel/next.js/blob/0eb377541648e63402a47b38fee00a8d0ce8f8f1/packages/next/src/server/lib/router-server.ts#L214-L250","documentation":"Error \"The CLI flag \"${cliServerFastRefresh === false ? '--no-server-fast-refresh' : '--server-fast-refresh'}\" conflicts with \"experimental.turbopackServerFastRefresh: ${configServerFastRefresh}\" in your Next.js config. The CLI flag will take precedence.\" thrown in vercel/next.js.","triggerScenarios":"Thrown at packages/next/src/server/lib/router-server.ts:232 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Remove either the CLI flag or `experimental.turbopackServerFastRefresh` from the config so they agree."],"exampleFix":null,"handlingStrategy":"validation","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":"2026-09-14T00:17:10.932Z"}