Move pagesDir handling out of wrappedRender (#40995)

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

packages/next/server/app-render.tsx

@@ -604,6 +604,8 @@ export async function renderToHTMLOrFlight(
   isPagesDir: boolean,
   isStaticGeneration: boolean = false
 ): Promise<RenderResult | null> {
+  const isFlight = req.headers.__rsc__ !== undefined
+
   const capturedErrors: Error[] = []
 
   const serverComponentsErrorHandler = createErrorHandler(
@@ -628,6 +630,32 @@ export async function renderToHTMLOrFlight(
     ComponentMod,
   } = renderOpts
 
+  // Handle client-side navigation to pages directory
+  // This is handled before
+  if (isFlight && isPagesDir) {
+    stripInternalQueries(query)
+    const search = stringifyQuery(query)
+
+    // For pages dir, there is only the SSR pass and we don't have the bundled
+    // React subset. Here we directly import the flight renderer with the
+    // unbundled React.
+    // TODO-APP: Is it possible to hard code the flight response here instead of
+    // rendering it?
+    const ReactServerDOMWebpack = require('next/dist/compiled/react-server-dom-webpack/writer.browser.server')
+
+    // Empty so that the client-side router will do a full page navigation.
+    const flightData: FlightData = pathname + (search ? `?${search}` : '')
+    return new FlightRenderResult(
+      ReactServerDOMWebpack.renderToReadableStream(
+        flightData,
+        serverComponentManifest,
+        {
+          onError: flightDataRendererErrorHandler,
+        }
+      ).pipeThrough(createBufferedTransformStream())
+    )
+  }
+
   patchFetch(ComponentMod)
 
   const staticGenerationAsyncStorage = ComponentMod.staticGenerationAsyncStorage
@@ -653,34 +681,8 @@ export async function renderToHTMLOrFlight(
     // don't modify original query object
     query = Object.assign({}, query)
 
-    const isFlight = req.headers.__rsc__ !== undefined
     const isPrefetch = req.headers.__next_router_prefetch__ !== undefined
 
-    // Handle client-side navigation to pages directory
-    if (isFlight && isPagesDir) {
-      stripInternalQueries(query)
-      const search = stringifyQuery(query)
-
-      // For pages dir, there is only the SSR pass and we don't have the bundled
-      // React subset. Here we directly import the flight renderer with the
-      // unbundled React.
-      // TODO-APP: Is it possible to hard code the flight response here instead of
-      // rendering it?
-      const ReactServerDOMWebpack = require('next/dist/compiled/react-server-dom-webpack/writer.browser.server')
-
-      // Empty so that the client-side router will do a full page navigation.
-      const flightData: FlightData = pathname + (search ? `?${search}` : '')
-      return new FlightRenderResult(
-        ReactServerDOMWebpack.renderToReadableStream(
-          flightData,
-          serverComponentManifest,
-          {
-            onError: flightDataRendererErrorHandler,
-          }
-        ).pipeThrough(createBufferedTransformStream())
-      )
-    }
-
     // TODO-APP: verify the tree is valid
     // TODO-APP: verify query param is single value (not an array)
     // TODO-APP: verify tree can't grow out of control