Error occurred prerendering page "/_not-found" with pageExtensions option

[Krasnopir]

Link to the code that reproduces this issue

https://codesandbox.io/p/devbox/misty-glade-yh92cc

To Reproduce

After update to 14.2.* version, when i use pageExtensions in next.config, i got an error while try to build my app

module.exports = {
  pageExtensions: ['page.tsx', 'page.ts'],
}

i have in my app folder all files with .page.tsx -

app:
- error.page.tsx
- global-error.page.tsx
- not-found.page.tsx
- layout.page.tsx
- page.page.tsx

Current vs. Expected behavior

Build app fail with pageExtentions option

✓ Linting and checking validity of types    
 ✓ Collecting page data    
   Generating static pages (0/8)  [=   ]
Error occurred prerendering page "/_not-found". Read more: https://nextjs.org/docs/messages/prerender-error

TypeError: Cannot read properties of undefined (reading 'clientModules')
    at /home/ui/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:16:23603
    at /home/ui/node_modules/next/dist/server/lib/trace/tracer.js:191:62
    at /home/ui/node_modules/next/dist/server/lib/trace/tracer.js:140:36
    at NoopContextManager.with (/home/ui/node_modules/@opentelemetry/api/build/src/context/NoopContextManager.js:25:19)
    at ContextAPI.with (/home/node_modules/@opentelemetry/api/build/src/api/context.js:60:46)
    at NoopTracer.startActiveSpan (/home/ui/node_modules/@opentelemetry/api/build/src/trace/NoopTracer.js:65:31)
    at ProxyTracer.startActiveSpan (/home/ui/node_modules/@opentelemetry/api/build/src/trace/ProxyTracer.js:36:24)
    at /home/ui/node_modules/next/dist/server/lib/trace/tracer.js:122:103
    at NoopContextManager.with (/home/ui/node_modules/@opentelemetry/api/build/src/context/NoopContextManager.js:25:19)
    at ContextAPI.with (/home/ui/node_modules/@opentelemetry/api/build/src/api/context.js:60:46)
 ✓ Generating static pages (8/8)

> Export encountered errors on following paths:
	/_not-found/page: /_not-found

Provide environment information

Operating System:
  Platform: linux
  Arch: x64
  Version: #29~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Thu Apr  4 14:39:20 UTC 2
  Available memory (MB): 15622
  Available CPU cores: 12
Binaries:
  Node: 20.12.2
  npm: 10.5.0
  Yarn: 1.22.19
  pnpm: N/A
Relevant Packages:
  next: 14.2.3 // Latest available version is detected (14.2.3).
  eslint-config-next: 14.2.3
  react: 18.2.0
  react-dom: 18.2.0
  typescript: 5.4.5
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Not sure

Which stage(s) are affected? (Select all that apply)

next build (local)

Additional context

No response

[sergejreznik]

I have suddenly the same error. There were no changes made and this error happens when deploying the application.
Build locally works fine, vercel deploy throws this error.

TypeError: Cannot read properties of null (reading 'auth')
--
16:38:14.053 | at a (/vercel/path0/.next/server/chunks/625.js:6:215122)
16:38:14.053 | at O (/vercel/path0/.next/server/chunks/625.js:6:174074)
16:38:14.053 | at /vercel/path0/.next/server/chunks/625.js:6:175009
16:38:14.053 | at Object.nr [as useMemo] (/vercel/path0/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:12:39088)
16:38:14.053 | at t.useMemo (/vercel/path0/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:12:106635)
16:38:14.053 | at /vercel/path0/.next/server/chunks/625.js:6:174977
16:38:14.053 | at nP (/vercel/path0/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:12:58441)
16:38:14.053 | at n$ (/vercel/path0/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:12:61978)
16:38:14.053 | at nE (/vercel/path0/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:12:44877)
16:38:14.053 | at nP (/vercel/path0/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:12:58448)
16:38:14.105 |  
16:38:14.105 | Error occurred prerendering page "/_not-found". Read more: https://nextjs.org/docs/messages/prerender-error
16:38:14.105 | TypeError: Cannot read properties of null (reading 'auth')
16:38:14.105 | at a (/vercel/path0/.next/server/chunks/625.js:6:215122)
16:38:14.105 | at O (/vercel/path0/.next/server/chunks/625.js:6:174074)
16:38:14.105 | at /vercel/path0/.next/server/chunks/625.js:6:175009
16:38:14.106 | at Object.nr [as useMemo] (/vercel/path0/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:12:39088)
16:38:14.106 | at t.useMemo (/vercel/path0/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:12:106635)
16:38:14.106 | at /vercel/path0/.next/server/chunks/625.js:6:174977
16:38:14.106 | at nP (/vercel/path0/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:12:58441)
16:38:14.106 | at n$ (/vercel/path0/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:12:61978)
16:38:14.109 | at nE (/vercel/path0/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:12:44877)
16:38:14.109 | at nP (/vercel/path0/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:12:58448)
16:38:14.536 | Generating static pages (11/44)
16:38:18.106 | Generating static pages (22/44)
16:38:20.328 | Generating static pages (33/44)
16:38:21.301 | ✓ Generating static pages (44/44)
16:38:21.311 |  
16:38:21.313 | > Export encountered errors on following paths:
16:38:21.313 | /_not-found

[awmottaz]

I went spelunking in the code, and this looks suspicious to me:

next.js/packages/next/src/server/app-render/app-render.tsx

Lines 693 to 694 in c1f8d93

	// TODO: fix this typescript
	const clientReferenceManifest = renderOpts.clientReferenceManifest!

This non-null assertion means clientReferenceManifest could actually be null or undefined and TypeScript won't check it. If it's undefined, you'll get the TypeError: Cannot read properties of undefined (reading 'clientModules') on, say, line 946:

next.js/packages/next/src/server/app-render/app-render.tsx

Lines 944 to 951 in c1f8d93

	const serverStream = ComponentMod.renderToReadableStream(
	<ReactServerApp tree={tree} ctx={ctx} asNotFound={asNotFound} />,
	clientReferenceManifest.clientModules,
	{
	onError: serverComponentsErrorHandler,
	nonce,
	}
	)

My guess is that this issue was introduced here: #64313

But I definitely don't have enough knowledge or context to confirm that or offer a suggestion on how to fix this

[awmottaz]

Another thing I found — after running a build, looking at the .next/app-paths-manifest.json file, I see an entry for "/_not-found/page": "app/_not-found/page.js". I also noticed that for every other entry in there, there is a corresponding <bundlename>-client-reference-manifest.js, but this file is missing for the not-found page.

# notice that a file shows up for every page entry
# but is missing for the not-found page
find .next/ -path '*client-reference-manifest.js'

I'm guessing that this missing file corresponds to an undefined clientReferenceManifest I mentioned in my last comment.

When I downgrade to v14.1.4, I see a couple of differences:

• The not-found page is built to .next/server/app/_not-found.js (instead of .next/server/app/_not-found/page.js in v14.2.3)
• The file .next/server/app/_not-found_client-reference-manifest.js exists

---

I now think this bug was caused by #62679

[awmottaz]

Maybe this if statement evaluates to false when using page extensions?

next.js/packages/next/src/build/webpack/plugins/flight-client-entry-plugin.ts

Lines 349 to 352 in c1f8d93

	if (
	name === `app${UNDERSCORE_NOT_FOUND_ROUTE_ENTRY}` &&
	bundlePath === 'app/not-found'
	) {

[awmottaz]

Here's a minimal reproduction https://github.com/awmottaz/next-typeerror-not-found

[riccardolardi]

I have the same issue, builds fine locally but on Vercel I get this error:

[20:37:58.035] Running build in Washington, D.C., USA (East) – iad1
[20:37:59.058] Cloning github.com/riccardolardi/maybeparis-next (Branch: main, Commit: 2875c34)
[20:37:59.894] Cloning completed: 835.705ms
[20:38:04.646] Restored build cache
[20:38:04.883] Running "vercel build"
[20:38:05.934] Vercel CLI 34.1.10
[20:38:06.673] Installing dependencies...
[20:38:07.448] yarn install v1.22.19
[20:38:07.646] [1/4] Resolving packages...
[20:38:08.138] [2/4] Fetching packages...
[20:38:08.146] warning Pattern ["strip-ansi-cjs@npm:strip-ansi@^6.0.1"] is trying to unpack in the same destination "/vercel/.cache/yarn/v6/npm-strip-ansi-cjs-6.0.1-9e26c63d30f53443e9489495b2105d37b67a85d9-integrity/node_modules/strip-ansi-cjs" as pattern ["strip-ansi@^6.0.1"]. This could result in non-deterministic behavior, skipping.
[20:38:08.146] warning Pattern ["string-width@^4.1.0"] is trying to unpack in the same destination "/vercel/.cache/yarn/v6/npm-string-width-cjs-4.2.3-269c7117d27b05ad2e536830a8ec895ef9c6d010-integrity/node_modules/string-width-cjs" as pattern ["string-width-cjs@npm:string-width@^4.2.0"]. This could result in non-deterministic behavior, skipping.
[20:38:08.146] warning Pattern ["strip-ansi@^6.0.0"] is trying to unpack in the same destination "/vercel/.cache/yarn/v6/npm-strip-ansi-cjs-6.0.1-9e26c63d30f53443e9489495b2105d37b67a85d9-integrity/node_modules/strip-ansi-cjs" as pattern ["strip-ansi@^6.0.1"]. This could result in non-deterministic behavior, skipping.
[20:38:32.651] [3/4] Linking dependencies...
[20:38:32.652] warning " > urql@4.1.0" has unmet peer dependency "@urql/core@^5.0.0".
[20:38:37.594] [4/4] Building fresh packages...
[20:38:37.611] Done in 30.17s.
[20:38:37.660] Detected Next.js version: 14.2.3
[20:38:37.662] Running "yarn run build"
[20:38:37.869] yarn run v1.22.19
[20:38:37.892] $ next build
[20:38:38.676]   ▲ Next.js 14.2.3
[20:38:38.676] 
[20:38:38.751]    Creating an optimized production build ...
[20:38:52.305]  ✓ Compiled successfully
[20:38:52.306]    Linting and checking validity of types ...
[20:38:59.325]    Collecting page data ...
[20:38:59.842] TypeError [ERR_INVALID_URL]: Invalid URL
[20:38:59.842]     at new NodeError (node:internal/errors:405:5)
[20:38:59.842]     at new URL (node:internal/url:676:13)
[20:38:59.843]     at 6192 (/vercel/path0/.next/server/app/_not-found/page.js:1:4320)
[20:38:59.843]     at t (/vercel/path0/.next/server/webpack-runtime.js:1:128)
[20:38:59.843]     at 338 (/vercel/path0/.next/server/app/_not-found/page.js:1:954)
[20:38:59.843]     at t (/vercel/path0/.next/server/webpack-runtime.js:1:128)
[20:38:59.844]     at n (/vercel/path0/.next/server/app/_not-found/page.js:43:75)
[20:38:59.848]     at /vercel/path0/.next/server/app/_not-found/page.js:43:106
[20:38:59.848]     at t.X (/vercel/path0/.next/server/webpack-runtime.js:1:1206)
[20:38:59.848]     at /vercel/path0/.next/server/app/_not-found/page.js:43:88 {
[20:38:59.848]   input: 'undefined',
[20:38:59.848]   code: 'ERR_INVALID_URL'
[20:38:59.849] }
[20:38:59.849] 
[20:38:59.849] > Build error occurred
[20:38:59.849] Error: Failed to collect page data for /_not-found
[20:38:59.849]     at /vercel/path0/node_modules/next/dist/build/utils.js:1268:15
[20:38:59.849]     at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
[20:38:59.849]   type: 'Error'
[20:38:59.849] }
[20:38:59.887] error Command failed with exit code 1.
[20:38:59.888] info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
[20:38:59.927] Error: Command "yarn run build" exited with 1
[20:39:00.377] 

[riccardolardi]

Since today the build suddenly succeeds... must've been something related to Vercel?

[quantafire]

Since today the build suddenly succeeds... must've been something related to Vercel?

Not Vercel. I'm struggling with local builds and our AWS server is spitting out the same error too

[jon-dez]

Another thing I found — after running a build, looking at the .next/app-paths-manifest.json file, I see an entry for "/_not-found/page": "app/_not-found/page.js". I also noticed that for every other entry in there, there is a corresponding <bundlename>-client-reference-manifest.js, but this file is missing for the not-found page.

# notice that a file shows up for every page entry
# but is missing for the not-found page
find .next/ -path '*client-reference-manifest.js'

I'm guessing that this missing file corresponds to an undefined clientReferenceManifest I mentioned in my last comment.

When I downgrade to v14.1.4, I see a couple of differences:

* The not-found page is built to `.next/server/app/_not-found.js` (instead of `.next/server/app/_not-found/page.js` in v14.2.3)

* The file `.next/server/app/_not-found_client-reference-manifest.js` exists

I now think this bug was caused by #62679

Downgraded to 14.1.4 from my package.json, and I can confirm I no longer see the following error:

> Export encountered errors on following paths:
	/_not-found/page: /_not-found

[yanv1991]

experiencing same issue after upgrade to 15-rc

[petrosmm]

Since today the build suddenly succeeds... must've been something related to Vercel?

What version is working for you?

[riccardolardi]

Since today the build suddenly succeeds... must've been something related to Vercel?

What version is working for you?

I think my problem was that I was having page.tsx inside an (index) folder. Taking it out there solved the issue if I remember correctly

[petrosmm]

Since today the build suddenly succeeds... must've been something related to Vercel?

What version is working for you?

I think my problem was that I was having page.tsx inside an (index) folder. Taking it out there solved the issue if I remember correctly

thank you for the quick reply. I don't have my index page inside a folder. But again would help to know what version you're using of 14 or if it's a canary of 15?

[riccardolardi]

Since today the build suddenly succeeds... must've been something related to Vercel?

What version is working for you?

I think my problem was that I was having page.tsx inside an (index) folder. Taking it out there solved the issue if I remember correctly

thank you for the quick reply. I don't have my index page inside a folder. But again would help to know what version you're using of 14 or if it's a canary of 15?

I'm using latest 14