Error: invariant: dynamic responses cannot be unchunked

[todorpopov93]

Verify canary release

• I verified that the issue exists in the latest Next.js canary release

Provide environment information

A next 13 production build hosted on GCP Kubernetes

Which area(s) of Next.js are affected? (leave empty if unsure)

No response

Link to the code that reproduces this issue

it's a private repository and I cannot share the code. I think it should be easily reproducible

To Reproduce

Just run the latest Nextjs 13 on production

Describe the Bug

Hello,

I have recently installed the latest next 13 ("next": "13.1.4"), and ran it on production (despite being experimental yet) and started receiving occasional error logs on the server side. However, the web app itself loads properly and everything works normally so far (2 days up time on production).

Here is the error:

Error: invariant: dynamic responses cannot be unchunked. This is a bug in Next.js at RenderResult.toUnchunkedString (/usr/src/app/node_modules/next/dist/server/render-result.js:16:19) at /usr/src/app/node_modules/next/dist/server/response-cache/index.js:103:57 at processTicksAndRejections (node:internal/process/task_queues:96:5)

Expected Behavior

Not to have this bug log in Next 13 I suppose

Which browser are you using? (if relevant)

No response

How are you deploying your application? (if relevant)

No response

[itsuki0927]

+1

[Arctomachine]

Encountered this issue at 13.0.6. Other than getting it seemingly randomly, one situation where it was triggered is running online schema validator

[github-actions]

We cannot recreate the issue with the provided information. Please add a reproduction in order for us to be able to investigate.

Why was this issue marked with the please add a complete reproduction label?

To be able to investigate, we need access to a reproduction to identify what triggered the issue. We prefer a link to a public GitHub repository (template), but you can also use a tool like CodeSandbox or StackBlitz.

To make sure the issue is resolved as quickly as possible, please make sure that the reproduction is as minimal as possible. This means that you should remove unnecessary code, files, and dependencies that do not contribute to the issue.

Please test your reproduction against the latest version of Next.js (next@canary) to make sure your issue has not already been fixed.

I added a link, why was it still marked?

Ensure the link is pointing to a codebase that is accessible (e.g. not a private repository). "example.com", "n/a", "will add later", etc. are not acceptable links -- we need to see a public codebase. See the above section for accepted links.

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Useful Resources

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[Clarity-89]

Happened to me as well, with app directory enabled. Seems like it was caused by another error, in this case I was desctructuring const post = allPosts.find((p) => p.id === id), where post was occasionally undefined. Fixing that error also removed the dynamic responses cannot be unchunked error, so I'd suggest to check if you have any other errors in your app that may cause this.

Edit: Nevermind, seems like error still appears randomly on production. Started happening after upgrading to Next.js 13.2.3 and switching to app directory.

[thevuong]

Screen.Recording.2023-03-13.at.10.32.23.PM.mov

I also get the same error when I upgrade to version 13.2.4, in version 13.2.3 I don't get that error.

I confirm that the error occurs when the User-Agent is a bot like Google Bot Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; Googlebot/2.1; +http://www.google.com/bot.html) Chrome/110.0.5481.177 Safari/537.36 and the page must have not been visited before.

[Arctomachine]

Since you figured out how it is triggered, did you perhaps find severity of this bug? Does it make something work worse or does it just leave error in log without breaking anything (requesting bot included)?

[todorpopov93]

Happened to me as well, with app directory enabled. Seems like it was caused by another error, in this case I was desctructuring const post = allPosts.find((p) => p.id === id), where post was occasionally undefined. Fixing that error also removed the dynamic responses cannot be unchunked error, so I'd suggest to check if you have any other errors in your app that may cause this.

Edit: Nevermind, seems like error still appears randomly on production. Started happening after upgrading to Next.js 13.2.3 and switching to app directory.

the problem is that for me it's happening since 13.1.4, but that was the first version that I did try and also ran on prodution, so it might be occurring from even earlier versions. And the worst is that I cannot give any steps to reproduce it, as I haven't done anything special.. having 1 page, 1 fetch and react components loaded is something that I don't think has anything special on it..
I think the issue lies somewhere within nextjs package itself, but it's not specific/not detailed and can't understand how to have it fixed (if possible at all).

[todorpopov93]

I also get the same error when I upgrade to version 13.2.4, in version 13.2.3 I don't get that error.

I would try this out with increasing my version to 13.2.3 and will leave feedback here if it worked for me. Thank you!

[davidbnk]

I'm experiencing this in production as well, next v13.2.4
Have no clue how to reproduce it because I never saw it during dev and there is no useful information in the error message

[Arctomachine]

Still happens in 13.3. This error makes up most of production logs, being outputed regularly.
Is there relation to hosting type? In my case server is self hosted on vps.

[PassTheMayo]

This error is still happening on NextJS 13.4.1. I'm currently using the app directory without Turbo if that helps at all.

[somersby10ml]

next 13.4.1 AppRouter is in use and

yarn build->yarn start `

After a few hours or days, you will see an error and the
server is not working.

Error: invariant: dynamic responses cannot be unchunked. This is a bug in Next.js
node_modules\next\dist\server\response-cache\index.js:119:57
node_modules\next\dist\server\render-result.js:28:19

[nithin-murali-arch]

I was using a custom server implementation, where I use app.renderToHTML. This causes the issue for me.

[cloetensbrecht]

We're getting the same issue in v 13.4.4 with AppRouter.
The website works fine, but the error log is full of these types of errors.
The server is a Windows server running PM2.

Error: invariant: dynamic responses cannot be unchunked. This is a bug in Next.js
	at RenderResult.toUnchunkedString (C:\wwwNodeJs\*****\node_modules\next\dist\server\render-result.js:28:19)
	at C:\wwwNodeJs\*****\node_modules\next\dist\server\response-cache\index.js:119:57

In node_modules\next\dist\server\render-result.js:

toUnchunkedString() {
	if (typeof this._result !== "string") {
		throw new Error("invariant: dynamic responses cannot be unchunked. This is a bug in Next.js");
	}
	return this._result;
}

next.js/packages/next/src/server/render-result.ts

Line 49 in e4b2306

'invariant: dynamic responses cannot be unchunked. This is a bug in Next.js'

[AGalbe]

We're getting the same issue in v 13.4.4 with AppRouter. The website works fine, but the error log is full of these types of errors. The server is a Windows server running PM2.

Error: invariant: dynamic responses cannot be unchunked. This is a bug in Next.js
	at RenderResult.toUnchunkedString (C:\wwwNodeJs\*****\node_modules\next\dist\server\render-result.js:28:19)
	at C:\wwwNodeJs\*****\node_modules\next\dist\server\response-cache\index.js:119:57

In node_modules\next\dist\server\render-result.js:

toUnchunkedString() {
	if (typeof this._result !== "string") {
		throw new Error("invariant: dynamic responses cannot be unchunked. This is a bug in Next.js");
	}
	return this._result;
}

next.js/packages/next/src/server/render-result.ts

Line 49 in e4b2306

'invariant: dynamic responses cannot be unchunked. This is a bug in Next.js'

I'm getting the same error v 13.4.4. Did you solve it? Thanks!

[charnog]

Was resolved in #52581

[balazsorban44]

Closing as per the above comment. Feel free to reopen with a new reproduction if you are still seeing this!

[github-actions]

This closed issue has been automatically locked because it had no new activity for 2 weeks. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.