Disable isNavigatingToNewRootLayout

packages/next/server/app-render.tsx

@@ -7,7 +7,7 @@ import type { FontLoaderManifest } from '../build/webpack/plugins/font-loader-ma
 // @ts-ignore
 import React, { experimental_use as use } from 'react'
 
-import { ParsedUrlQuery, stringify as stringifyQuery } from 'querystring'
+import { ParsedUrlQuery } from 'querystring'
 import { createFromReadableStream } from 'next/dist/compiled/react-server-dom-webpack'
 import { NextParsedUrlQuery } from './request-meta'
 import RenderResult from './render-result'
@@ -668,56 +668,6 @@ async function renderToString(element: React.ReactElement) {
   return streamToString(renderStream)
 }
 
-function getRootLayoutPath(
-  [segment, parallelRoutes, { layout }]: LoaderTree,
-  rootLayoutPath = ''
-): string | undefined {
-  rootLayoutPath += `${segment}/`
-  const isLayout = typeof layout !== 'undefined'
-  if (isLayout) return rootLayoutPath
-  // We can't assume it's `parallelRoutes.children` here in case the root layout is `app/@something/layout.js`
-  // But it's not possible to be more than one parallelRoutes before the root layout is found
-  const child = Object.values(parallelRoutes)[0]
-  if (!child) return
-  return getRootLayoutPath(child, rootLayoutPath)
-}
-
-function findRootLayoutInFlightRouterState(
-  [segment, parallelRoutes]: FlightRouterState,
-  rootLayoutSegments: string,
-  segments = ''
-): boolean {
-  segments += `${segment}/`
-  if (segments === rootLayoutSegments) {
-    return true
-  } else if (segments.length > rootLayoutSegments.length) {
-    return false
-  }
-  // We can't assume it's `parallelRoutes.children` here in case the root layout is `app/@something/layout.js`
-  // But it's not possible to be more than one parallelRoutes before the root layout is found
-  const child = Object.values(parallelRoutes)[0]
-  if (!child) return false
-  return findRootLayoutInFlightRouterState(child, rootLayoutSegments, segments)
-}
-
-function isNavigatingToNewRootLayout(
-  loaderTree: LoaderTree,
-  flightRouterState: FlightRouterState
-): boolean {
-  const newRootLayout = getRootLayoutPath(loaderTree)
-  // should always have a root layout
-  if (newRootLayout) {
-    const hasSameRootLayout = findRootLayoutInFlightRouterState(
-      flightRouterState,
-      newRootLayout
-    )
-
-    return !hasSameRootLayout
-  }
-
-  return false
-}
-
 export async function renderToHTMLOrFlight(
   req: IncomingMessage,
   res: ServerResponse,
@@ -810,28 +760,6 @@ export async function renderToHTMLOrFlight(
      */
     const loaderTree: LoaderTree = ComponentMod.tree
 
-    // If navigating to a new root layout we need to do a full page navigation.
-    if (
-      isFlight &&
-      Array.isArray(providedFlightRouterState) &&
-      isNavigatingToNewRootLayout(loaderTree, providedFlightRouterState)
-    ) {
-      stripInternalQueries(query)
-      const search = stringifyQuery(query)
-
-      // Empty so that the client-side router will do a full page navigation.
-      const flightData: FlightData = req.url! + (search ? `?${search}` : '')
-      return new FlightRenderResult(
-        ComponentMod.renderToReadableStream(
-          flightData,
-          serverComponentManifest,
-          {
-            onError: flightDataRendererErrorHandler,
-          }
-        ).pipeThrough(createBufferedTransformStream())
-      )
-    }
-
     stripInternalQueries(query)
 
     const LayoutRouter =

test/e2e/app-dir/root-layout.test.ts

@@ -4,7 +4,7 @@ import { NextInstance } from 'test/lib/next-modes/base'
 import webdriver from 'next-webdriver'
 import { getRedboxSource, hasRedbox } from 'next-test-utils'
 
-describe('app-dir root layout', () => {
+describe.skip('app-dir root layout', () => {
   const isDev = (global as any).isNextDev
 
   if ((global as any).isNextDeploy) {