Regression in 12.0.8 for jest: TypeError: require.resolveWeak is not a function

[zmarty]

Run next info (available from version 12.0.8 and up)

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 10 Enterprise
Binaries:
  Node: 16.8.0
  npm: 7.21.0
  Yarn: 1.22.10
  pnpm: N/A
Relevant packages:
  next: 12.0.8
  react: 17.0.2
  react-dom: 17.0.2

What version of Next.js are you using?

12.0.8

What version of Node.js are you using?

16.8.0

What browser are you using?

Edge (Chromium)

What operating system are you using?

Windows 11 Enterprise (by the way, why does next info say I am using Windows 10??)

How are you deploying your application?

On Azure App Service as docker container

Describe the Bug

We have a Next.js website where the unit tests are using Jest. When I try to upgrade the website from Next.js 12.0.7 to 12.0.8 the unit tests which test code that uses dynamic code loading start failing.

It looks to me this is related to this previously closed bug, which would make this a regression for Next.js 12.0.8: TypeError: require.resolveWeak is not a function (jest test) #19862

Example output

  ● Test suite failed to run

    TypeError: require.resolveWeak is not a function

    > 29 | const HeaderSearchBoxMobile = dynamic(() => import('../HeaderSearchBox/HeaderSearchBoxMobile/HeaderSearchBoxMobile'));

Expected Behavior

Tests should pass even if the code they test uses dynamic()

To Reproduce

Run a Jest test where the test code tests some code that uses dynamic() to load some other code.

[balazsorban44]

Based on your reproduction, I could not reproduce this issue. Could you create one that I can have a look at?

On next info: OS version is reported by the native os.version() Node.js API, so it's not much we can do about that. Probably related to the Node.js version you are using, maybe you have to update Node.js.

[Parnswir]

We see the same issue in our code base (closed source, sorry): with next@12.0.8 tests fail when running jest; with next@12.0.7 everything is fine. Strangely, running jest --coverage works fine on both versions.

[balazsorban44]

Hi, @Parnswir, thanks! Please create a small public reproduction then 🙏 I cannot see the issue, so it might be related to your project specifically. Try reducing the number of pages/components/code until a point it can be shared and the issue still reproduces.

Here is a good resource on this topic.

[Parnswir]

https://codesandbox.io/s/next-dynamic-22ejz

if you fork it on codesandbox, you can run npm test in the terminal on the right (click the + icon). On next@12.0.8 (which is installed in this sandbox), the test will fail. If you downgrade to next@12.0.7 (select the version in the dependecies list on the left), the test will pass.

Often, when the codesandbox container hangs; you can restart the next server from the menu on the left:

[balazsorban44]

Hmm. Thanks for the CodeSandbox, it is helpful! I recognized you did not follow the test setup from https://nextjs.org/docs/testing

Applying those seems to solve the problem. Could you try it?

@zmarty are you using a custom/Babel setup for your test environment? Could you share it?

[duc-gp]

Hmm. Thanks for the CodeSandbox, it is helpful! I recognized you did not follow the test setup from https://nextjs.org/docs/testing

Applying those seems to solve the problem. Could you try it?

@zmarty are you using a custom/Babel setup for your test environment? Could you share it?

What exactly are you referring to or what exactly did you changed in the codesandbox to make the test run? Can you provide a link?

[zmarty]

@zmarty are you using a custom/Babel setup for your test environment? Could you share it?

So far we have tried to repro this on an empty Next.js instance and we can't.

We stopped using a custom babel setup for the website entirely a few versions ago.

I do see we use some custom webpack config in next.config.js, so we'll be looking at that as well. Inside the unit tests folder I only see that we set up some mocks.

[duc-gp]

We also tried on an the https://github.com/vercel/next.js/tree/canary/examples/with-jest example and there it works.

Unfortunately we still need babel, otherwise we cannot use jest's automock functionality. I've forked and provided an example here:
https://github.com/vercel/next.js/compare/canary...duc-gp:example-jest-automock-not-working?expand=1

• run npm run test example.test.js to start the test
• when you outcomment the transform in jest.config.js + delete the .babelrc so babel is not used, the test does not work anymore

[balazsorban44]

@duc-gp Do note we provide a babel setup as well:

• https://github.com/vercel/next.js/tree/canary/examples/with-jest-babel
• https://nextjs.org/docs/testing#setting-up-jest-with-babel

[duc-gp]

@duc-gp Do note we provide a babel setup as well:

• https://github.com/vercel/next.js/tree/canary/examples/with-jest-babel
• https://nextjs.org/docs/testing#setting-up-jest-with-babel

@balazsorban44 thanks, ive just checked out the setup you mentioned and added a simple test:
https://github.com/vercel/next.js/compare/canary...duc-gp:example-jest-automock-not-working-with-nextjs-babel-setup?expand=1

when you run npm run test DummyA.test.js you can see the error TypeError: require.resolveWeak is not a function

[balazsorban44]

Interesting, I could not reproduce still:

Could you add an actual repository link so I can verify this?

[duc-gp]

Interesting, I could not reproduce still:

Could you add an actual repository link so I can verify this?

what exactly did you do to try to reproduce this? from what setup is your screenshot from?
the link to the repository is: https://github.com/duc-gp/next.js/tree/example-jest-automock-not-working-with-nextjs-babel-setup

• switch to the branch example-jest-automock-not-working-with-nextjs-babel-setup !
• go into examples/with-jest-babel
• npm i
• npm run test DummyA.test.js

edit: I just tried the same steps on another machine and could reproduce this as well

node versions I've tried:

• v14.16.0
• v16.13.0

[balazsorban44]

I tried a totally clean project again with yarn create next-app -e with-babel-jest, added your modifications, and finally reproduced it. 👍

[PsyGik]

Thank you for reporting this. I was upgrading a project to Next.js 12 and the CI just barfed all over with the error TypeError: require.resolveWeak is not a function.

On another note, the Upgrade Guide does not specify the changes that need to be done to setup Jest with the Rust compiler when upgrading to Next 12. It'd be nice to have the docs updated please.

[timneutkens]

Found the problem, opening a PR with a new test that covers this case.

[timneutkens]

This is released on canary 🎉 Please try it out: npm install next@canary.

[ryparker]

This is released on canary 🎉 Please try it out: npm install next@canary.

Works for me 👍🏻 Thanks!

[timneutkens]

Great 👍 This is out on stable in 12.1

[github-actions]

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