skip postpone to do dynamic render

Author: huozhi

packages/next/src/server/app-render/app-render.tsx

@@ -1847,18 +1847,9 @@ async function renderToStream(
     // one task before continuing
     await waitAtLeastOneReactRenderTask()
 
-    // When streaming metadata is enabled and request UA is a html-limited bot, we should do a dynamic render.
-    const shouldDoDynamicRender =
-      ctx.renderOpts.botType === 'html' &&
-      ctx.renderOpts.experimental.streamingMetadata
-
     // If provided, the postpone state should be parsed as JSON so it can be
     // provided to React.
-    if (
-      typeof renderOpts.postponed === 'string' &&
-      // When we don't need to forcedly do a dynamic render, continue PPR renderer.
-      !shouldDoDynamicRender
-    ) {
+    if (typeof renderOpts.postponed === 'string') {
       if (postponedState?.type === DynamicState.DATA) {
         // We have a complete HTML Document in the prerender but we need to
         // still include the new server component render because it was not included

packages/next/src/server/base-server.ts

@@ -175,7 +175,10 @@ import type { RouteModule } from './route-modules/route-module'
 import { FallbackMode, parseFallbackField } from '../lib/fallback'
 import { toResponseCacheEntry } from './response-cache/utils'
 import { scheduleOnNextTick } from '../lib/scheduler'
-import { shouldServeStreamingMetadata } from './lib/streaming-metadata'
+import {
+  shouldServeStreamingMetadata,
+  shouldSkipPostponedState,
+} from './lib/streaming-metadata'
 
 export type FindComponentsResult = {
   components: LoadComponentsReturnType
@@ -2097,6 +2100,11 @@ export default abstract class Server<
     const hasDebugFallbackShellQuery =
       hasDebugStaticShellQuery && query.__nextppronly === 'fallback'
 
+    const skipPostponed = shouldSkipPostponedState(
+      req,
+      this.renderOpts.experimental.streamingMetadata
+    )
+
     // This page supports PPR if it is marked as being `PARTIALLY_STATIC` in the
     // prerender manifest and this is an app page.
     const isRoutePPREnabled: boolean =
@@ -2443,7 +2451,7 @@ export default abstract class Server<
         isOnDemandRevalidate,
         isDraftMode: isPreviewMode,
         isServerAction,
-        postponed,
+        postponed: skipPostponed ? undefined : postponed,
         waitUntil: this.getWaitUntil(),
         onClose: res.onClose.bind(res),
         onAfterTaskError: undefined,

packages/next/src/server/lib/streaming-metadata.ts

@@ -1,4 +1,8 @@
-import { HTML_LIMITED_BOT_UA_RE_STRING } from '../../shared/lib/router/utils/is-bot'
+import {
+  getBotType,
+  HTML_LIMITED_BOT_UA_RE_STRING,
+} from '../../shared/lib/router/utils/is-bot'
+import type { BaseNextRequest } from '../base-http'
 
 export function shouldServeStreamingMetadata(
   userAgent: string,
@@ -23,3 +27,15 @@ export function shouldServeStreamingMetadata(
     !!userAgent && !blockingMetadataUARegex.test(userAgent)
   )
 }
+
+// When streaming metadata is enabled and request UA is a html-limited bot, we should do a dynamic render.
+// In this case, postpone state is not sent.
+export function shouldSkipPostponedState(
+  req: BaseNextRequest,
+  streamingMetadata: boolean
+): boolean {
+  const ua = req.headers['user-agent'] || ''
+  const botType = getBotType(ua)
+
+  return botType === 'html' && streamingMetadata
+}

test/e2e/app-dir/ppr-metadata-streaming/app/layout.tsx

@@ -2,7 +2,6 @@ import Link from 'next/link'
 import { ReactNode } from 'react'
 
 const hrefs = [
-  '/',
   '/dynamic-metadata',
   '/dynamic-metadata/partial',
   '/dynamic-page',