Is there an existing issue for this?

• I have searched the existing issues
• I am using the latest npm

Current Behavior

Running npm install --omit=dev in a workspace monorepo with install-strategy=linked crashes:

npm warn reify The "linked" install strategy is EXPERIMENTAL and may contain bugs.
npm error Cannot read properties of undefined (reading 'isProjectRoot')

Without --omit=dev, install works fine.

Expected Behavior

Should install only production dependencies without crashing.

Steps To Reproduce

mkdir -p /tmp/repro/packages/my-lib && cd /tmp/repro

cat > package.json << 'EOF'
{
  "name": "my-monorepo",
  "private": true,
  "workspaces": ["packages/*"],
  "dependencies": {
    "abbrev": "^2.0.0"
  },
  "devDependencies": {
    "semver": "^7.6.0"
  }
}
EOF

cat > packages/my-lib/package.json << 'EOF'
{
  "name": "my-lib",
  "version": "1.0.0",
  "dependencies": {
    "abbrev": "^2.0.0"
  },
  "devDependencies": {
    "lru-cache": "^10.0.0"
  }
}
EOF

echo "install-strategy=linked" > .npmrc

npm install --omit=dev   # crashes
npm install              # works fine

Root Cause

addOmitsToTrashList in reify.js iterates idealTree.inventory and reads node.top.isProjectRoot. With linked strategy, createIsolatedTree() in isolated-reifier.js builds proxy node objects — but the workspace and workspace link proxies are missing the top property entirely, so accessing top.isProjectRoot throws.

Note: this is v10-only. npm 11 removed addOmitsToTrashList and moved omit handling into the diff calculation.

Environment

• npm: 10.9.5
• Node.js: 22.20.0
• OS Name: macOS (Darwin 25.3.0)
• npm config:

  install-strategy=linked