re-enable streaming metadata with PPR

packages/next/src/build/index.ts

@@ -2784,10 +2784,7 @@ export default async function build(
               },
               // If it's PPR rendered non-static page, bypass the PPR cache when streaming metadata is enabled.
               // This will skip the postpone data for those bots requests and instead produce a dynamic render.
-              ...(isRoutePPREnabled &&
-              // Disable streaming metadata for PPR on deployment where we don't have the special env.
-              // TODO: enable streaming metadata in PPR mode by default once it's ready.
-              process.env.__NEXT_EXPERIMENTAL_PPR === 'true'
+              ...(isRoutePPREnabled
                 ? [
                     {
                       type: 'header',

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

@@ -433,17 +433,6 @@ function NonIndex({ ctx }: { ctx: AppRenderContext }) {
   return null
 }
 
-function getServeStreamingMetadata(ctx: AppRenderContext) {
-  const isRoutePPREnabled = !!ctx.renderOpts.experimental.isRoutePPREnabled
-  const serveStreamingMetadata = !!ctx.renderOpts.serveStreamingMetadata
-  // If the route is in PPR and the special env is not set, disable the streaming metadata.
-  // TODO: enable streaming metadata in PPR mode by default once it's ready.
-  if (isRoutePPREnabled && process.env.__NEXT_EXPERIMENTAL_PPR !== 'true') {
-    return false
-  }
-  return serveStreamingMetadata
-}
-
 /**
  * This is used by server actions & client-side navigations to generate RSC data from a client-side request.
  * This function is only called on "dynamic" requests (ie, there wasn't already a static response).
@@ -483,7 +472,7 @@ async function generateDynamicRSCPayload(
     url,
   } = ctx
 
-  const serveStreamingMetadata = getServeStreamingMetadata(ctx)
+  const serveStreamingMetadata = !!ctx.renderOpts.serveStreamingMetadata
 
   if (!options?.skipFlight) {
     const preloadCallbacks: PreloadCallbacks = []
@@ -803,7 +792,7 @@ async function getRSCPayload(
     getDynamicParamFromSegment,
     query
   )
-  const serveStreamingMetadata = getServeStreamingMetadata(ctx)
+  const serveStreamingMetadata = !!ctx.renderOpts.serveStreamingMetadata
 
   const searchParams = createServerSearchParamsForMetadata(query, workStore)
   const {
@@ -941,7 +930,7 @@ async function getErrorRSCPayload(
     workStore,
   } = ctx
 
-  const serveStreamingMetadata = getServeStreamingMetadata(ctx)
+  const serveStreamingMetadata = !!ctx.renderOpts.serveStreamingMetadata
   const searchParams = createServerSearchParamsForMetadata(query, workStore)
   const { MetadataTree, ViewportTree } = createMetadataComponents({
     tree,

test/production/app-dir/metadata-streaming-config/metadata-streaming-config-customized.test.ts

@@ -1,8 +1,5 @@
 import { nextTestSetup } from 'e2e-utils'
 
-// TODO: remove this env once streaming metadata is available for ppr
-process.env.__NEXT_EXPERIMENTAL_PPR = 'true'
-
 describe('app-dir - metadata-streaming-config-customized', () => {
   const { next, skipped } = nextTestSetup({
     files: __dirname,

test/production/app-dir/metadata-streaming-config/metadata-streaming-config.test.ts

@@ -1,8 +1,5 @@
 import { nextTestSetup } from 'e2e-utils'
 
-// TODO: remove this env once streaming metadata is available for ppr
-process.env.__NEXT_EXPERIMENTAL_PPR = 'true'
-
 describe('app-dir - metadata-streaming-config', () => {
   const { next, skipped } = nextTestSetup({
     files: __dirname,