[webpack 5] Yarn v2 can't resolve file loader in docs plugin

[RDIL]

🐛 Bug Report

On webpack 5, Yarn 2 can't resolve file-loader when building docs.

Have you read the Contributing Guidelines on issues?

Yes

To Reproduce

Clone https://github.com/rdilweb/rdil.rocks and update the Docusaurus version in the /docs project - then yarn && yarn build.

Expected behavior

Build passes.

Actual Behavior

file-loader not found error.

Your Environment

• Public source code: https://github.com/rdilweb/rdil.rocks
• Public site url: https://rdil.rocks/docs
• Docusaurus version used: alpha 75
• Environment name and version: Debian LTS, Node 14.16.1
• Operating system and version (desktop or mobile): Debian LTS

Reproducible Demo

https://github.com/rdilweb/rdil.rocks

[slorber]

It's something I noticed during the Webpack 5 PR.

Our Yarn2 e2e test did not use the latest version of Docusaurus.
After I fixed it, Yarn2 failed due to this missing file-loader.
As a temporary solution, added the file-loader to the init template sites so it can build on Yarn2.

This should be fixed once we migrate to the new assets system: #4708

[HazyFish]

Any update on this? The PR has been inactive for 2 months now. The temporary solution doesn't work although I have file-loader and url-loader as dependencies.

Module not found: Error: Can't resolve 'url' in '.yarn\$$virtual\@docusaurus-core-virtual-ee257a6165\0\cache\@docusaurus-core-npm-2.0.0-beta.3-e31061f4c9-86b35725e9.zip\node_modules\@docusaurus\core\lib\webpack\react-dev-utils-webpack5'
BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.
This is no longer the case. Verify if you need this module and configure a polyfill for it.

If you want to include a polyfill, you need to:
        - add a fallback 'resolve.fallback: { "url": require.resolve("url/") }'
        - install 'url'
If you don't want to include a polyfill, you can use an empty module like this:
        resolve.fallback: { "url": false }

[slorber]

@HazyFish this PR is stuck until I figure out a proper way to solve this problem: webpack/webpack#12900 (comment)
(any help welcome)

Your issue does not look related to Yarn2/file-loader/url-loader but more about Webpack not polyfilling nodejs modules anymore.
https://blog.sindresorhus.com/webpack-5-headache-b6ac24973bf1

You can add the missing polyfills yourself if you need to: create a local docusaurus plugin that modify the existing Webpack configuration to add that polyfill

[hhaoao]

oh, Is there any progress on this issue?
I installed these two missing packages and it works fine.

testing-library/testing-library-docs#928

pnpm add url-loader @mdx-js/react