feat(v2): Use pnp-webpack-plugin to support pnp module resolution

[SamChou19815]

Motivation

According to the discussion in #2795, I think we should add pnp-webpack-plugin directly to docusaurus core to enable a zero-config experience for yarn pnp users. It adds very little space overhead to non-pnp users: adding this to an empty projects only creates a 20kb node_modules.

Note

After testing it on a local project after manually apply my pnp fix changes, including this one, I found that we are still one or two diffs away from fully supporting Yarn pnp mode. Here are some problems I found so far:

• Some code in the docs and blog plugin still uses plain string to refer to plugins. (Fixed in fix(v2): Consistently use require.resolve in official plugins to resolve modules #2797)
• There are some issues of requires with generated code.
  • client-modules.js related issues fixed in fix(v2): Consistently use require.resolve in official plugins to resolve modules #2797
  • @mdx-js/react issue (generated blog code has import { mdx } from '@mdx-js/react'), we might need to recommend pnp users to add @mdx-js/react as a dependency to fix this.
• Some react dependencies of docusaurus doesn't properly declare their dependencies.
  • We might need to instruct users to use pnpMode: loose as a workaround.

Have you read the Contributing Guidelines on pull requests?

Yes

Test Plan

• Check the docs to see the config is correct: https://github.com/arcanis/pnp-webpack-plugin#usage
• Everything still builds.

Related PRs

(If this PR adds or changes functionality, please take some time to update the docs at https://github.com/facebook/docusaurus, and link to your PR here.)

[docusaurus-bot]

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[slorber]

Hi @SamChou19815

Don't exactly know what is happening but I'm unable to build the core project (the module is present in node_modules, I did rm -rf node_modules and yarn install).

Was wondering if yarn2 or a specific version of nodeJS was required to make it work.

I'm on:
node v12.16.1
yatn 1.21.1

Any idea?

[SamChou19815]

@slorber I am unable to reproduce this problem. I'm on latest master, Yarn 1.22.4, node 12.14.1. I guess you need to rm -rf **/node_modules, or manually remove the build folders?

[slorber]

Ah sorry it's working after deleting /lib

I think it has something to do with incremental TS compilation and the .tsbuildinfo file