This demonstrates an issue the DllPlugin/DllReferencePlugin when running Yarn 2 when it uses virtual paths.

Pre-requisites

yarn@~1.22.0 installed globally

Run

dll-lib - build bundle + manifest

cd dll-lib
yarn set version berry # set yarn to v2
yarn # install
yarn webpack

lib-user - build bundle + use manifest from dll-lib

cd lib-user
yarn set version berry # set yarn to v2
yarn # install
yarn webpack

Expected

The bundle in lib-user makes a reference to react-dom in it's bundle by using library-manifest.json in dll-lib.

Actual

react-dom is bundled into lib-user/dist/index.js.

Notes

In library-manifest.json in dll-lib the reference is a yarn 2 virtual package.

{
  "name": "library_1109ed9bec109636950b",
  "content": {
    "./.yarn/$$virtual/react-dom-virtual-4970a0b490/0/cache/react-dom-npm-16.12.0-4ea576dd1a-2.zip/node_modules/react-dom/index.js": {
      "id": 601,
      "buildMeta": {}
    }
  }
}

When the webpack build in dll-user runs, it looks for react-dom but the path it has in .pnp.js is:

"packageLocation": "./.yarn/$$virtual/react-dom-virtual-76a393ef8c/0/cache/react-dom-npm-16.12.0-4ea576dd1a-2.zip/node_modules/react-dom/",

From reading the yarn docs here and here it looks like these virtual paths are unique to disambiguate packages that list peerDependencies. So while they both point to the same package the virtual path will not be the same. This will prevent the reference being be pulled in as the paths won't match.