Make notFound() work in "use cache" page

packages/next/src/server/app-render/create-error-handler.tsx

@@ -22,7 +22,7 @@ type SSRErrorHandler = (
 export type DigestedError = Error & { digest: string }
 
 export function createFlightReactServerErrorHandler(
-  dev: boolean,
+  shouldFormatError: boolean,
   onReactServerRenderError: (err: DigestedError) => void
 ): RSCErrorHandler {
   return (thrownValue: unknown) => {
@@ -56,7 +56,7 @@ export function createFlightReactServerErrorHandler(
     }
 
     // Format server errors in development to add more helpful error messages
-    if (dev) {
+    if (shouldFormatError) {
       formatServerError(err)
     }
 
@@ -77,7 +77,7 @@ export function createFlightReactServerErrorHandler(
 }
 
 export function createHTMLReactServerErrorHandler(
-  dev: boolean,
+  shouldFormatError: boolean,
   isNextExport: boolean,
   reactServerErrors: Map<string, DigestedError>,
   silenceLogger: boolean,
@@ -120,7 +120,7 @@ export function createHTMLReactServerErrorHandler(
     }
 
     // Format server errors in development to add more helpful error messages
-    if (dev) {
+    if (shouldFormatError) {
       formatServerError(err)
     }
 
@@ -153,7 +153,7 @@ export function createHTMLReactServerErrorHandler(
 }
 
 export function createHTMLErrorHandler(
-  dev: boolean,
+  shouldFormatError: boolean,
   isNextExport: boolean,
   reactServerErrors: Map<string, DigestedError>,
   allCapturedErrors: Array<unknown>,
@@ -200,7 +200,7 @@ export function createHTMLErrorHandler(
     }
 
     // Format server errors in development to add more helpful error messages
-    if (dev) {
+    if (shouldFormatError) {
       formatServerError(err)
     }
 

packages/next/src/server/use-cache/use-cache-wrapper.ts

@@ -38,6 +38,7 @@ import type { CacheHandler, CacheEntry } from '../lib/cache-handlers/types'
 import type { CacheSignal } from '../app-render/cache-signal'
 import { decryptActionBoundArgs } from '../app-render/encryption'
 import { InvariantError } from '../../shared/lib/invariant-error'
+import { createFlightReactServerErrorHandler } from '../app-render/create-error-handler'
 
 const isEdgeRuntime = process.env.NEXT_RUNTIME === 'edge'
 
@@ -330,11 +331,17 @@ async function generateCacheEntryImpl(
       environmentName: 'Cache',
       signal: controller.signal,
       temporaryReferences,
-      onError(error: unknown) {
-        // Report the error.
+      // In the "Cache" environment, we only need to make sure that the error
+      // digests are handled correctly. Error formatting and reporting is not
+      // necessary here; the errors are encoded in the stream, and will be
+      // reported in the "Server" environment.
+      onError: createFlightReactServerErrorHandler(false, (error: unknown) => {
+        // TODO: For now we're also reporting the error here, because in
+        // production, the "Server" environment will only get the obfuscated
+        // error (created by the Flight Client in the cache wrapper).
         console.error(error)
         errors.push(error)
-      },
+      }),
     }
   )
 

test/e2e/app-dir/use-cache/app/not-found/page.tsx

@@ -0,0 +1,9 @@
+'use cache'
+
+import { notFound } from 'next/navigation'
+
+export default async function Page() {
+  notFound()
+
+  return <p>This will never render</p>
+}

test/e2e/app-dir/use-cache/use-cache.test.ts

@@ -452,4 +452,10 @@ describe('use-cache', () => {
       expect(await browser.elementByCss('p').text()).toBe(value)
     })
   })
+
+  it('renders the not-found page when `notFound()` is used', async () => {
+    const browser = await next.browser('/not-found')
+    const text = await browser.elementByCss('h2').text()
+    expect(text).toBe('This page could not be found.')
+  })
 })