test: add some test cases ensuring next.config redirects/rewrites don't result in cache poisoning

Author: pieh

tests/e2e/simple-app.test.ts

@@ -1,4 +1,4 @@
-import { expect, type Locator } from '@playwright/test'
+import { expect, type Locator, type Response } from '@playwright/test'
 import { nextVersionSatisfies } from '../utils/next-version-helpers.mjs'
 import { test } from '../utils/playwright-helpers.js'
 
@@ -282,3 +282,59 @@ test('can require CJS module that is not bundled', async ({ simple }) => {
   expect(parsedBody.notBundledCJSModule.isBundled).toEqual(false)
   expect(parsedBody.bundledCJSModule.isBundled).toEqual(true)
 })
+
+test.describe('RSC cache poisoning', () => {
+  test('Next.config.js rewrite', async ({ page, simple }) => {
+    const prefetchResponsePromise = new Promise<Response>((resolve) => {
+      page.on('response', (response) => {
+        if (response.url().includes('/config-rewrite/source')) {
+          resolve(response)
+        }
+      })
+    })
+    await page.goto(`${simple.url}/config-rewrite`)
+
+    // ensure prefetch
+    await page.hover('text=NextConfig.rewrite')
+
+    // wait for prefetch request to finish
+    const prefetchResponse = await prefetchResponsePromise
+
+    // ensure prefetch respond with RSC data
+    expect(prefetchResponse.headers()['content-type']).toMatch(/text\/x-component/)
+    expect(prefetchResponse.headers()['netlify-cdn-cache-control']).toMatch(/s-maxage=31536000/)
+
+    const htmlResponse = await page.goto(`${simple.url}/config-rewrite/source`)
+
+    // ensure we get HTML response
+    expect(htmlResponse?.headers()['content-type']).toMatch(/text\/html/)
+    expect(htmlResponse?.headers()['netlify-cdn-cache-control']).toMatch(/s-maxage=31536000/)
+  })
+
+  test('Next.config.js redirect', async ({ page, simple }) => {
+    const prefetchResponsePromise = new Promise<Response>((resolve) => {
+      page.on('response', (response) => {
+        if (response.url().includes('/config-redirect/dest')) {
+          resolve(response)
+        }
+      })
+    })
+    await page.goto(`${simple.url}/config-redirect`)
+
+    // ensure prefetch
+    await page.hover('text=NextConfig.redirect')
+
+    // wait for prefetch request to finish
+    const prefetchResponse = await prefetchResponsePromise
+
+    // ensure prefetch respond with RSC data
+    expect(prefetchResponse.headers()['content-type']).toMatch(/text\/x-component/)
+    expect(prefetchResponse.headers()['netlify-cdn-cache-control']).toMatch(/s-maxage=31536000/)
+
+    const htmlResponse = await page.goto(`${simple.url}/config-rewrite/source`)
+
+    // ensure we get HTML response
+    expect(htmlResponse?.headers()['content-type']).toMatch(/text\/html/)
+    expect(htmlResponse?.headers()['netlify-cdn-cache-control']).toMatch(/s-maxage=31536000/)
+  })
+})

tests/fixtures/simple/app/config-redirect/dest/page.tsx

@@ -0,0 +1,9 @@
+export default function Page() {
+  return (
+    <main>
+      <h1>Hello redirect target</h1>
+    </main>
+  )
+}
+
+export const dynamic = 'force-static'

tests/fixtures/simple/app/config-redirect/page.tsx

@@ -0,0 +1,9 @@
+import Link from 'next/link'
+
+export default function Home() {
+  return (
+    <div>
+      <Link href="/config-redirect/source">NextConfig.redirect</Link>
+    </div>
+  )
+}

tests/fixtures/simple/app/config-rewrite/dest/page.tsx

@@ -0,0 +1,9 @@
+export default function Page() {
+  return (
+    <main>
+      <h1>Hello rewrite target</h1>
+    </main>
+  )
+}
+
+export const dynamic = 'force-static'

tests/fixtures/simple/app/config-rewrite/page.tsx

@@ -0,0 +1,9 @@
+import Link from 'next/link'
+
+export default function Home() {
+  return (
+    <div>
+      <Link href="/config-rewrite/source">NextConfig.rewrite</Link>
+    </div>
+  )
+}

tests/fixtures/simple/next-env.d.ts

@@ -0,0 +1,5 @@
+/// <reference types="next" />
+/// <reference types="next/image-types/global" />
+
+// NOTE: This file should not be edited
+// see https://nextjs.org/docs/app/api-reference/config/typescript for more information.

tests/fixtures/simple/next.config.js

@@ -29,6 +29,19 @@ const nextConfig = {
         destination: 'https://example.vercel.sh',
         basePath: false,
       },
+      {
+        source: '/config-rewrite/source',
+        destination: '/config-rewrite/dest',
+      },
+    ]
+  },
+  async redirects() {
+    return [
+      {
+        source: '/config-redirect/source',
+        destination: '/config-redirect/dest',
+        permanent: true,
+      },
     ]
   },
 }

tests/fixtures/simple/package.json

@@ -11,5 +11,8 @@
     "next": "latest",
     "react": "18.2.0",
     "react-dom": "18.2.0"
+  },
+  "devDependencies": {
+    "@types/react": "19.1.2"
   }
 }

tests/fixtures/simple/tsconfig.json

@@ -0,0 +1,24 @@
+{
+  "compilerOptions": {
+    "target": "ES2017",
+    "lib": ["dom", "dom.iterable", "esnext"],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "strict": false,
+    "noEmit": true,
+    "incremental": true,
+    "module": "esnext",
+    "esModuleInterop": true,
+    "moduleResolution": "node",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "jsx": "preserve",
+    "plugins": [
+      {
+        "name": "next"
+      }
+    ]
+  },
+  "include": ["next-env.d.ts", ".next/types/**/*.ts", "**/*.ts", "**/*.tsx"],
+  "exclude": ["node_modules"]
+}