fix: fixed headers returned with PPR and fixed force-dynamic static d…

…etection

packages/next/src/build/index.ts

@@ -161,6 +161,9 @@ import type { BuildTraceContext } from './webpack/plugins/next-trace-entrypoints
 import { formatManifest } from './manifests/formatter/format-manifest'
 import { getStartServerInfo, logStartInfo } from '../server/lib/app-info-log'
 import type { NextEnabledDirectories } from '../server/base-server'
+import createDebug from 'next/dist/compiled/debug'
+
+const debug = createDebug('next:build')
 
 interface ExperimentalBypassForInfo {
   experimentalBypassFor?: RouteHas[]
@@ -1654,6 +1657,8 @@ export default async function build(
                         }
                       )
 
+                      debug(`page ${page} isPageStatic:`, workerResult)
+
                       if (pageType === 'app' && originalAppPath) {
                         appNormalizedPaths.set(originalAppPath, page)
                         // TODO-APP: handle prerendering with edge
@@ -1694,7 +1699,10 @@ export default async function build(
                           }
 
                           const appConfig = workerResult.appConfig || {}
-                          if (appConfig.revalidate !== 0) {
+
+                          // Configure the page to be static if the revalidation
+                          // time isn't zero or the page has PPR enabled.
+                          if (appConfig.revalidate !== 0 || isPPR) {
                             const isDynamic = isDynamicRoute(page)
                             const hasGenerateStaticParams =
                               !!workerResult.prerenderRoutes?.length
@@ -2294,10 +2302,11 @@ export default async function build(
               )
             }
 
-            if (hasDynamicData && pageInfo.isStatic) {
-              // If the page was marked as being static, but it contains dynamic
-              // data (ie, in the case of a static generation bailout), then it
-              // should be marked dynamic.
+            // If the page was marked as being static, but it contains dynamic
+            // data (ie, in the case of a static generation bailout), then it
+            // should be marked dynamic. If PPR is enabled for this route
+            // though, it should continue to be marked as static.
+            if (hasDynamicData && pageInfo.isStatic && !pageInfo.isPPR) {
               pageInfo.isStatic = false
               pageInfo.isSSG = false
             }
@@ -2393,14 +2402,23 @@ export default async function build(
                 }
               } else {
                 hasDynamicData = true
-                // we might have determined during prerendering that this page
-                // used dynamic data
-                pageInfo.isStatic = false
-                pageInfo.isSSG = false
+
+                // We might have determined during prerendering that this page
+                // used dynamic data. If PPR is enabled, it should be marked
+                // as static.
+                if (!pageInfo.isPPR) {
+                  pageInfo.isStatic = false
+                  pageInfo.isSSG = false
+                }
               }
             })
 
-            if (!hasDynamicData && isDynamicRoute(originalAppPath)) {
+            // Add the route as a supported dynamic route if it has no data
+            // requirements or if PPR is enabled.
+            if (
+              (!hasDynamicData || pageInfo.isPPR) &&
+              isDynamicRoute(originalAppPath)
+            ) {
               const { dataRoute, prefetchDataRoute } = createAppDataRouteInfo(
                 page,
                 {

packages/next/src/build/utils.ts

@@ -1488,6 +1488,7 @@ export async function isPageStatic({
       let encodedPrerenderRoutes: Array<string> | undefined
       let prerenderFallback: boolean | 'blocking' | undefined
       let appConfig: AppConfig = {}
+      let isPPR = false
       let isClientComponent: boolean = false
       const pathIsEdgeRuntime = isEdgeRuntime(pageRuntime)
 
@@ -1594,16 +1595,19 @@ export async function isPageStatic({
           {}
         )
 
+        if (ppr && routeModule.definition.kind === RouteKind.APP_PAGE) {
+          isPPR = true
+        }
+
         if (appConfig.dynamic === 'force-static' && pathIsEdgeRuntime) {
           Log.warn(
             `Page "${page}" is using runtime = 'edge' which is currently incompatible with dynamic = 'force-static'. Please remove either "runtime" or "force-static" for correct behavior`
           )
         }
 
-        // If force dynamic was set and we don't have PPR enabled, then set the
-        // revalidate to 0.
-        // TODO: (PPR) remove this once PPR is enabled by default
-        if (appConfig.dynamic === 'force-dynamic' && !ppr) {
+        // When `dynamic = "force-dynamic"`, we should not retain the value in
+        // the cache.
+        if (appConfig.dynamic === 'force-dynamic') {
           appConfig.revalidate = 0
         }
 
@@ -1693,18 +1697,10 @@ export async function isPageStatic({
         )
       }
 
-      let isStatic = false
-      if (!hasStaticProps && !hasGetInitialProps && !hasServerProps) {
-        isStatic = true
-      }
+      const hasDynamicData =
+        hasStaticProps || hasGetInitialProps || hasServerProps
 
-      // When PPR is enabled, any route may contain or be completely static, so
-      // mark this route as static.
-      let isPPR = false
-      if (ppr && routeModule.definition.kind === RouteKind.APP_PAGE) {
-        isPPR = true
-        isStatic = true
-      }
+      const isStatic = isPPR || !hasDynamicData
 
       return {
         isStatic,
@@ -2098,7 +2094,7 @@ export function getPossibleInstrumentationHookFilenames(
   folder: string,
   extensions: string[]
 ) {
-  const files = []
+  const files: string[] = []
   for (const extension of extensions) {
     files.push(
       path.join(folder, `${INSTRUMENTATION_HOOK_FILENAME}.${extension}`),

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

@@ -1294,7 +1294,7 @@ export default abstract class Server<ServerOptions extends Options = Options> {
           }
 
           res.statusCode = Number(req.headers['x-invoke-status'])
-          let err = null
+          let err: Error | null = null
 
           if (typeof req.headers['x-invoke-error'] === 'string') {
             const invokeError = JSON.parse(
@@ -2601,7 +2601,18 @@ export default abstract class Server<ServerOptions extends Options = Options> {
       return null
     }
 
-    if (isSSG && !this.minimalMode) {
+    const didPostpone =
+      cacheEntry.value?.kind === 'PAGE' && !!cacheEntry.value.postponed
+
+    if (
+      isSSG &&
+      !this.minimalMode &&
+      // We don't want to send a cache header for requests that contain dynamic
+      // data. If this is a Dynamic RSC request or wasn't a Prefetch RSC
+      // request, then we should set the cache header.
+      !isDynamicRSCRequest &&
+      (!didPostpone || isPrefetchRSCRequest)
+    ) {
       // set x-nextjs-cache header to match the header
       // we set for the image-optimizer
       res.setHeader(
@@ -2813,7 +2824,12 @@ export default abstract class Server<ServerOptions extends Options = Options> {
           return {
             type: 'rsc',
             body: cachedData.html,
-            revalidate: cacheEntry.revalidate,
+            // Dynamic RSC responses cannot be cached, even if they're
+            // configured with `force-static` because we have no way of
+            // distinguishing between `force-static` and pages that have no
+            // postponed state.
+            // TODO: distinguish `force-static` from pages with no postponed state (static)
+            revalidate: 0,
           }
         }
 
@@ -2881,7 +2897,10 @@ export default abstract class Server<ServerOptions extends Options = Options> {
       return {
         type: 'html',
         body,
-        revalidate: cacheEntry.revalidate,
+        // We don't want to cache the response if it has postponed data because
+        // the response being sent to the client it's dynamic parts are streamed
+        // to the client on the same request.
+        revalidate: 0,
       }
     } else if (isDataReq) {
       return {

test/e2e/app-dir/ppr-full/app/dynamic/force-dynamic/nested/[slug]/page.jsx

@@ -0,0 +1,20 @@
+import React, { Suspense } from 'react'
+import { Dynamic } from '../../../../../components/dynamic'
+
+export const dynamic = 'force-dynamic'
+
+export function generateStaticParams() {
+  return []
+}
+
+export default ({ params: { slug } }) => {
+  return (
+    <Suspense
+      fallback={
+        <Dynamic pathname={`/dynamic/force-dynamic/nested/${slug}`} fallback />
+      }
+    >
+      <Dynamic pathname={`/dynamic/force-dynamic/nested/${slug}`} />
+    </Suspense>
+  )
+}

test/e2e/app-dir/ppr-full/app/dynamic/force-dynamic/page.jsx

@@ -3,14 +3,10 @@ import { Dynamic } from '../../../components/dynamic'
 
 export const dynamic = 'force-dynamic'
 
-export default ({ params: { slug } }) => {
+export default () => {
   return (
-    <Suspense
-      fallback={
-        <Dynamic pathname={`/dynamic/force-dynamic/${slug}`} fallback />
-      }
-    >
-      <Dynamic pathname={`/dynamic/force-dynamic/${slug}`} />
+    <Suspense fallback={<Dynamic pathname="/dynamic/force-dynamic" fallback />}>
+      <Dynamic pathname="/dynamic/force-dynamic" />
     </Suspense>
   )
 }

test/e2e/app-dir/ppr-full/app/dynamic/force-static/page.jsx

@@ -4,12 +4,10 @@ import { Dynamic } from '../../../components/dynamic'
 export const dynamic = 'force-static'
 export const revalidate = 60
 
-export default ({ params: { slug } }) => {
+export default () => {
   return (
-    <Suspense
-      fallback={<Dynamic pathname={`/dynamic/force-static/${slug}`} fallback />}
-    >
-      <Dynamic pathname={`/dynamic/force-static/${slug}`} />
+    <Suspense fallback={<Dynamic pathname="/dynamic/force-static" fallback />}>
+      <Dynamic pathname="/dynamic/force-static" />
     </Suspense>
   )
 }

test/e2e/app-dir/ppr-full/app/static/page.jsx

@@ -1,6 +1,3 @@
-import React from 'react'
-import { Dynamic } from '../../components/dynamic'
-
 export default () => {
-  return <Dynamic pathname="/static" fallback />
+  return 'Static'
 }

test/e2e/app-dir/ppr-full/components/dynamic.jsx

@@ -3,7 +3,7 @@ import { headers } from 'next/headers'
 
 export const Dynamic = ({ pathname, fallback }) => {
   if (fallback) {
-    return <div>Loading...</div>
+    return <div>Dynamic Loading...</div>
   }
 
   const messages = []
@@ -28,7 +28,7 @@ export const Dynamic = ({ pathname, fallback }) => {
             <dt>
               Header: <code>{name}</code>
             </dt>
-            <dd>{value ?? 'null'}</dd>
+            <dd>{value ?? `MISSING:${name.toUpperCase()}`}</dd>
           </React.Fragment>
         ))}
       </dl>