next.js: Error: invariant: dynamic responses cannot be unchunked

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

About this issue

Original URL
State: closed
Created a year ago
Reactions: 10
Comments: 18 (3 by maintainers)

Most upvoted comments

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

nithin-murali-arch on May 17, 2023

Was resolved in https://github.com/vercel/next.js/pull/52581

charnog on Jul 13, 2023

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;
}
https://github.com/vercel/next.js/blob/e4b230677c24744ff2a2253a475d271c38d1443f/packages/next/src/server/render-result.ts#L49

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

AGalbe on Jun 23, 2023

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;
}

https://github.com/vercel/next.js/blob/e4b230677c24744ff2a2253a475d271c38d1443f/packages/next/src/server/render-result.ts#L49

cloetensbrecht on Jun 7, 2023