yarn start errors out when building '@docusaurus/mdx-loader'

🐛 Bug Report

Prerequisites

• I’m using the latest version of Docusaurus.
• I have tried the npm run clear or yarn clear command.
• * I have tried rm -rf node_modules yarn.lock package-lock.json and re-installing packages. (* Entire project)
• * I have tried creating a repro with https://new.docusaurus.io (*No. Cloned the repository)
• I have read the console error message carefully (if applicable)

Description

Running yarn install and then yarn start, the builder stack traces when building '@docusaurus/mdx-loader'. At first I thought this might be me, so deleted, rinsed and repeated the clone. Same result. I also qualified what I had experienced, in Discord.

Have you read the Contributing Guidelines on issues?

Yup, I read the guidelines and followed the installation process as described, albeit direct from the repo.

I’m happy to raise a PR, as I believe I have found the type error on line 33 in packages/docusaurus-mdx-loader/src/remark/toc/index.ts.

Steps to reproduce

~Use https://new.docusaurus.io to create a CodeSandbox reproducible demo of the bug.~ I believe it is not possible to reproduce in CodeSandbox, as this is a stack trace during the build process.

1. git clone [e-mail]:facebook/docusaurus.git
2. yarn install
3. yarn start

Expected behavior

lerna info run Ran npm script 'build' in '@docusaurus/mdx-loader' in 4.5s:

Actual behavior

lerna ERR! yarn run build exited 2 in '@docusaurus/mdx-loader'
lerna ERR! yarn run build stdout:
src/remark/toc/index.ts(33,12): error TS2345: Argument of type 'File' is not assignable to parameter of type 'Node | Node[] | null | undefined'.
  Type 'import("/openSource/docusaurus/node_modules/@babel/parser/node_modules/@babel/types/lib/index").File' is not assignable to type 'babel.types.File'.
    The types of 'program.body' are incompatible between these types.
      Type 'import("/openSource/docusaurus/node_modules/@babel/parser/node_modules/@babel/types/lib/index").Statement[]' is not assignable to type 'babel.types.Statement[]'.
        Type 'import("/openSource/docusaurus/node_modules/@babel/parser/node_modules/@babel/types/lib/index").Statement' is not assignable to type 'babel.types.Statement'.
          Type 'BlockStatement' is not assignable to type 'Statement'.

lerna ERR! yarn run build exited 2 in '@docusaurus/mdx-loader'

Your environment

The versions of

• yarn version 3.0.1
• node version v14.4.0
• Ubuntu 20.04.3 LTS
• v2.0.0-beta.4

Reproducible demo

Happens with yarn start ~Use https://new.docusaurus.io to create a CodeSandbox reproducible demo of the bug.~

~(Paste the link to an example repo, including a docusaurus.config.js, and exact instructions to reproduce the issue.)~

[slorber]

Technically, this code is correct and is quite similar to the one documented here: https://babeljs.io/docs/en/babel-traverse

File is indeed a Node.

I suspect for some reason you end-up with a mismatch, maybe due to a duplicate dependency or something?

Try to run yarn why @babel/types and see if you have any duplicates.

Also, if you use Yarn 3 PNP linker, it may be worth trying the node-modules linker instead.

But I’d just suggest using Yarn 1 for now.

I’d be happy to move to newer versions someday but we don’t officially support that today.

Going to close because I’m not sure there’s anything to do here. Let me know if you still have problems with Yarn 1, or if you succeed to make it work with Yarn 3.

[slorber]

I guess we’ll never know 🤪 maybe when I’ll upgrade to Yarn 3