fix: set x-deployment-id to every middleware prefetch request

packages/next/src/shared/lib/router/router.ts

@@ -498,7 +498,10 @@ function fetchNextData({
       headers: Object.assign(
         {} as HeadersInit,
         isPrefetch ? { purpose: 'prefetch' } : {},
-        isPrefetch && hasMiddleware ? { 'x-middleware-prefetch': '1' } : {}
+        isPrefetch && hasMiddleware ? { 'x-middleware-prefetch': '1' } : {},
+        process.env.NEXT_DEPLOYMENT_ID
+          ? { 'x-deployment-id': process.env.NEXT_DEPLOYMENT_ID }
+          : {}
       ),
       method: params?.method ?? 'GET',
     })

test/production/deployment-id-handling/app/middleware.ts

@@ -0,0 +1,5 @@
+import { NextRequest, NextResponse } from 'next/server'
+
+export function middleware(_req: NextRequest) {
+  return NextResponse.next()
+}

test/production/deployment-id-handling/app/pages/index.tsx

@@ -1,13 +1,17 @@
 import testImage from '../public/test.jpg'
 import Image from 'next/image'
 import styles from './styles.module.css'
+import Link from 'next/link'
 
 export default function Page() {
   return (
     <>
       <p className={styles.template}>hello pages</p>
       <p id="deploymentId">{process.env.NEXT_DEPLOYMENT_ID}</p>
       <Image src={testImage} alt="test image" />
+      <Link href="/pages-edge" id="edge-link">
+        Edge
+      </Link>
 
       <button
         onClick={() => {

test/production/deployment-id-handling/app/pages/pages-edge.tsx

@@ -1,10 +1,10 @@
 import testImage from '../public/test.jpg'
 import Image from 'next/image'
 
-export default function Page() {
+export default function Page({ data }: { data: string }) {
   return (
     <>
-      <p>hello pages edge</p>
+      <h1>{data}</h1>
       <Image src={testImage} alt="test image" />
       <p id="deploymentId">{process.env.NEXT_DEPLOYMENT_ID}</p>
 
@@ -25,3 +25,11 @@ export default function Page() {
 export const config = {
   runtime: 'experimental-edge',
 }
+
+export function getServerSideProps() {
+  return {
+    props: {
+      data: 'hello pages edge',
+    },
+  }
+}

test/production/deployment-id-handling/deployment-id-handling.test.ts

@@ -84,6 +84,34 @@ describe.each(['NEXT_DEPLOYMENT_ID', 'CUSTOM_DEPLOYMENT_ID'])(
       }
     )
 
+    it('should contain deployment id in prefetch request', async () => {
+      const dataHeaders = []
+      const browser = await next.browser('/', {
+        beforePageLoad(page) {
+          page.on('request', async (req) => {
+            const headers = await req.allHeaders()
+            if (headers['x-nextjs-data']) {
+              dataHeaders.push(headers)
+            }
+          })
+        },
+      })
+
+      await browser.elementByCss('#edge-link').click()
+
+      await retry(async () => {
+        expect(await browser.elementByCss('h1').text()).toBe('hello pages edge')
+        expect(await browser.url()).toContain('/pages-edge')
+        expect(dataHeaders.length).toBeGreaterThan(0)
+      })
+
+      expect(
+        dataHeaders.every(
+          (headers) => headers['x-deployment-id'] === deploymentId
+        )
+      ).toBe(true)
+    })
+
     it('should contain deployment id in RSC payload request headers', async () => {
       const rscHeaders = []
       const browser = await next.browser('/from-app', {