Yarn PnP: `require.cache` and `require.extensions` are undefined in dependencies (regression in v22.22.3)

Version

v22.22.3 through v22.23.1

Platform

Darwin LMJ6QJLXY 25.5.0 Darwin Kernel Version 25.5.0: Mon Apr 27 20:41:12 PDT 2026; root:xnu-12377.121.6~2/RELEASE_ARM64_T6050 arm64

Subsystem

No response

What steps will reproduce the bug?

#!/usr/bin/env bash
#
# Save this script to a file named `repro.sh`, then run it:
#
#   bash repro.sh
#
# Without an argument, the script creates `node-yarn-pnp-repro` in the
# directory from which the script is run.
#
# Or choose the directory where the test project will be created:
#
#   bash repro.sh ./my-pnp-repro

set -euo pipefail

repro_dir="${1:-node-yarn-pnp-repro}"

if [[ -e "$repro_dir" ]]; then
  echo "Directory already exists: $repro_dir" >&2
  exit 1
fi

mkdir "$repro_dir"
cd "$repro_dir"

echo "Reproduction directory: $PWD"

cat > package.json <<'EOF'
{
  "name": "node-yarn-pnp-repro",
  "private": true,
  "packageManager": "yarn@4.16.0",
  "dependencies": {
    "autoprefixer": "10.4.2",
    "css-loader": "7.1.4",
    "postcss": "8.4.49",
    "postcss-loader": "8.2.1",
    "style-loader": "4.0.0",
    "tailwindcss": "3.4.15",
    "webpack": "5.108.1",
    "webpack-cli": "5.1.4"
  }
}
EOF

cat > .yarnrc.yml <<'EOF'
nodeLinker: pnp
enableGlobalCache: false
EOF

cat > tailwind.config.js <<'EOF'
module.exports = {
  content: ['./src/**/*.html'],
  theme: { extend: {} },
  plugins: [],
};
EOF

cat > postcss.config.js <<'EOF'
module.exports = {
  plugins: {
    tailwindcss: {},
    autoprefixer: {},
  },
};
EOF

mkdir src

cat > src/style.css <<'EOF'
@tailwind base;
@tailwind components;
@tailwind utilities;
EOF

cat > src/index.html <<'EOF'
<div class="text-red-500">hi</div>
EOF

cat > webpack.config.js <<'EOF'
const path = require('path');

module.exports = {
  mode: 'production',
  entry: './src/style.css',
  output: {
    path: path.resolve(__dirname, 'dist'),
    filename: 'bundle.js',
  },
  module: {
    rules: [
      {
        test: /\.css$/,
        use: ['style-loader', 'css-loader', 'postcss-loader'],
      },
    ],
  },
};
EOF

corepack yarn install
corepack yarn webpack

How often does it reproduce? Is there a required condition?

Every time with nodeLinker: pnp.

The same project succeeds with nodeLinker: node-modules on the same affected Node.js version.

What is the expected behavior? Why is that the expected behavior?

The build should succeed, as it does on Node.js v22.22.2 and earlier, and on Node.js v24.16.0 and later.

require.cache is documented as an object containing cached CommonJS modules.

Packages using Yarn PnP should continue to receive a require function with the standard CommonJS properties, including require.cache and require.extensions.

What do you see instead?

The build fails while webpack-cli loads webpack.config.js:

[webpack-cli] TypeError: Cannot convert undefined or null to object at Function.keys (<anonymous>) at exports.prepare (.../rechoir/index.js:21:14) at loadConfigByPath (.../webpack-cli/lib/webpack-cli.js:...) ...

rechoir calls Object.keys(require.extensions) at that location. Under Yarn PnP on affected Node.js versions, require.extensions is undefined.

The same underlying issue affects packages that access require.cache; for example, code such as delete require.cache[filePath] fails because require.cache is undefined.

Additional information

No response

Commencez par exécuter repro.sh avec Yarn Plug'n'Play sur les versions de Node.js concernées et comparez-le avec nodeLinker: node-modules ainsi qu’avec les versions non concernées indiquées. Examinez comment la fonction require est créée pour les dépendances, en prenant rechoir/index.js comme point d’entrée observé. La tâche est considérée comme terminée lorsque le build webpack réussit et que les fonctions require des dépendances exposent require.cache et require.extensions.