From 747d365004e722b7806ba4560edd4d85b51cb67e Mon Sep 17 00:00:00 2001
From: Jiachi Liu <inbox@huozhi.im>
Date: Mon, 9 Sep 2024 10:57:31 +0200
Subject: [PATCH] Fix metadata prop merging (#69807)

### What

Fixes metadata merging issue on 14.2. There's a bug with React  on 14.2 as it bit outdated: while generating rsc payload, if we use fragment to wrap the metadata and noindex component, it will miss all the data. It works well with separating them as an array.
It also requires #64058 to be applied as well so the output not-found page will having correct status 404, and then we can generate noindex metatag based on correct status

Fixes #69778
---
 .../next/src/server/app-render/app-render.tsx | 14 ++++-----
 .../app/(cart)/product/layout.tsx             | 13 ++++++++
 .../app/(cart)/product/page.tsx               |  3 ++
 .../app/@header/layout.tsx                    |  7 +++++
 .../metadata-navigation/app/@header/page.tsx  | 12 ++++++++
 .../app/@header/product/layout.tsx            |  7 +++++
 .../app/@header/product/page.tsx              | 12 ++++++++
 .../metadata-navigation/app/layout.tsx        | 23 ++++++++++++++
 .../app-dir/metadata-navigation/app/page.tsx  |  7 +++++
 .../metadata-navigation.test.ts               | 30 +++++++++++++++++++
 10 files changed, 120 insertions(+), 8 deletions(-)
 create mode 100644 test/e2e/app-dir/metadata-navigation/app/(cart)/product/layout.tsx
 create mode 100644 test/e2e/app-dir/metadata-navigation/app/(cart)/product/page.tsx
 create mode 100644 test/e2e/app-dir/metadata-navigation/app/@header/layout.tsx
 create mode 100644 test/e2e/app-dir/metadata-navigation/app/@header/page.tsx
 create mode 100644 test/e2e/app-dir/metadata-navigation/app/@header/product/layout.tsx
 create mode 100644 test/e2e/app-dir/metadata-navigation/app/@header/product/page.tsx
 create mode 100644 test/e2e/app-dir/metadata-navigation/app/layout.tsx
 create mode 100644 test/e2e/app-dir/metadata-navigation/app/page.tsx
 create mode 100644 test/e2e/app-dir/metadata-navigation/metadata-navigation.test.ts

diff --git a/packages/next/src/server/app-render/app-render.tsx b/packages/next/src/server/app-render/app-render.tsx
index d0005eb6e7148..d192970eec658 100644
--- a/packages/next/src/server/app-render/app-render.tsx
+++ b/packages/next/src/server/app-render/app-render.tsx
@@ -319,13 +319,11 @@ async function generateFlight(
         flightRouterState,
         isFirst: true,
         // For flight, render metadata inside leaf page
-        rscPayloadHead: (
-          <>
-            <NonIndex ctx={ctx} />
-            {/* Adding requestId as react key to make metadata remount for each render */}
-            <MetadataTree key={requestId} />
-          </>
-        ),
+        // NOTE: in 14.2, fragment doesn't work well with React, using array instead
+        rscPayloadHead: [
+          <MetadataTree key={requestId} />,
+          <NonIndex key="noindex" ctx={ctx} />,
+        ],
         injectedCSS: new Set(),
         injectedJS: new Set(),
         injectedFontPreloadTags: new Set(),
@@ -531,12 +529,12 @@ async function ReactServerError({
 
   const head = (
     <>
-      <NonIndex ctx={ctx} />
       {/* Adding requestId as react key to make metadata remount for each render */}
       <MetadataTree key={requestId} />
       {process.env.NODE_ENV === 'development' && (
         <meta name="next-error" content="not-found" />
       )}
+      <NonIndex ctx={ctx} />
     </>
   )
 
diff --git a/test/e2e/app-dir/metadata-navigation/app/(cart)/product/layout.tsx b/test/e2e/app-dir/metadata-navigation/app/(cart)/product/layout.tsx
new file mode 100644
index 0000000000000..1fae4138eb8a2
--- /dev/null
+++ b/test/e2e/app-dir/metadata-navigation/app/(cart)/product/layout.tsx
@@ -0,0 +1,13 @@
+import { Metadata } from 'next'
+
+export const metadata: Metadata = {
+  title: 'Product Layout',
+}
+
+export default function Layout({
+  children,
+}: Readonly<{
+  children: React.ReactNode
+}>) {
+  return <>{children}</>
+}
diff --git a/test/e2e/app-dir/metadata-navigation/app/(cart)/product/page.tsx b/test/e2e/app-dir/metadata-navigation/app/(cart)/product/page.tsx
new file mode 100644
index 0000000000000..6fda1b09db3e0
--- /dev/null
+++ b/test/e2e/app-dir/metadata-navigation/app/(cart)/product/page.tsx
@@ -0,0 +1,3 @@
+export default function Page() {
+  return <div>Product page content</div>
+}
diff --git a/test/e2e/app-dir/metadata-navigation/app/@header/layout.tsx b/test/e2e/app-dir/metadata-navigation/app/@header/layout.tsx
new file mode 100644
index 0000000000000..15286d515a67f
--- /dev/null
+++ b/test/e2e/app-dir/metadata-navigation/app/@header/layout.tsx
@@ -0,0 +1,7 @@
+type LayoutProps = {
+  children: React.ReactNode
+}
+
+export default function Layout({ children }: LayoutProps) {
+  return <div>{children}</div>
+}
diff --git a/test/e2e/app-dir/metadata-navigation/app/@header/page.tsx b/test/e2e/app-dir/metadata-navigation/app/@header/page.tsx
new file mode 100644
index 0000000000000..029e01e2ad355
--- /dev/null
+++ b/test/e2e/app-dir/metadata-navigation/app/@header/page.tsx
@@ -0,0 +1,12 @@
+import Link from 'next/link'
+
+export default function Page() {
+  return (
+    <div>
+      <div>Home header</div>
+      <Link href="/product" id="product-link">
+        Product
+      </Link>
+    </div>
+  )
+}
diff --git a/test/e2e/app-dir/metadata-navigation/app/@header/product/layout.tsx b/test/e2e/app-dir/metadata-navigation/app/@header/product/layout.tsx
new file mode 100644
index 0000000000000..cd0e8d61beece
--- /dev/null
+++ b/test/e2e/app-dir/metadata-navigation/app/@header/product/layout.tsx
@@ -0,0 +1,7 @@
+type LayoutProps = {
+  children: React.ReactNode
+}
+
+export default function Layout({ children }: LayoutProps) {
+  return <>{children}</>
+}
diff --git a/test/e2e/app-dir/metadata-navigation/app/@header/product/page.tsx b/test/e2e/app-dir/metadata-navigation/app/@header/product/page.tsx
new file mode 100644
index 0000000000000..11b27614e0630
--- /dev/null
+++ b/test/e2e/app-dir/metadata-navigation/app/@header/product/page.tsx
@@ -0,0 +1,12 @@
+import Link from 'next/link'
+
+export default function Page() {
+  return (
+    <div>
+      <h1 id="product-title">Product header</h1>
+      <Link href="/" id="home-link">
+        Go to Home page
+      </Link>
+    </div>
+  )
+}
diff --git a/test/e2e/app-dir/metadata-navigation/app/layout.tsx b/test/e2e/app-dir/metadata-navigation/app/layout.tsx
new file mode 100644
index 0000000000000..e05cd2dd3ed58
--- /dev/null
+++ b/test/e2e/app-dir/metadata-navigation/app/layout.tsx
@@ -0,0 +1,23 @@
+import type { Metadata } from 'next'
+
+export const metadata: Metadata = {
+  title: 'Home Layout',
+  description: 'Generated by create next app',
+}
+
+export default function RootLayout({
+  header,
+  children,
+}: Readonly<{
+  header: React.ReactNode
+  children: React.ReactNode
+}>) {
+  return (
+    <html lang="en">
+      <body className={`antialiased bg-gray-50 text-black`}>
+        {header}
+        {children}
+      </body>
+    </html>
+  )
+}
diff --git a/test/e2e/app-dir/metadata-navigation/app/page.tsx b/test/e2e/app-dir/metadata-navigation/app/page.tsx
new file mode 100644
index 0000000000000..92b0c4de98772
--- /dev/null
+++ b/test/e2e/app-dir/metadata-navigation/app/page.tsx
@@ -0,0 +1,7 @@
+export default function Home() {
+  return (
+    <div>
+      <h3 id="home-title">Home page content</h3>
+    </div>
+  )
+}
diff --git a/test/e2e/app-dir/metadata-navigation/metadata-navigation.test.ts b/test/e2e/app-dir/metadata-navigation/metadata-navigation.test.ts
new file mode 100644
index 0000000000000..10accfbc6d7c4
--- /dev/null
+++ b/test/e2e/app-dir/metadata-navigation/metadata-navigation.test.ts
@@ -0,0 +1,30 @@
+import { createNextDescribe } from 'e2e-utils'
+
+createNextDescribe(
+  'app-dir - metadata-navigation',
+  {
+    files: __dirname,
+  },
+  ({ next }) => {
+    it('should show the index title', async () => {
+      const browser = await next.browser('/')
+      expect(await browser.elementByCss('title').text()).toBe('Home Layout')
+    })
+
+    it('should show target page metadata after navigation', async () => {
+      const browser = await next.browser('/')
+      await browser.elementByCss('#product-link').click()
+      await browser.waitForElementByCss('#product-title')
+      expect(await browser.elementByCss('title').text()).toBe('Product Layout')
+    })
+
+    it('should show target page metadata after navigation with back', async () => {
+      const browser = await next.browser('/')
+      await browser.elementByCss('#product-link').click()
+      await browser.waitForElementByCss('#product-title')
+      await browser.elementByCss('#home-link').click()
+      await browser.waitForElementByCss('#home-title')
+      expect(await browser.elementByCss('title').text()).toBe('Home Layout')
+    })
+  }
+)