[BUG] install-strategy=linked: --workspaces=false and --include-workspace-root fail with invalid filterNode #9614

Part of #9608.

Is there an existing issue for this?

• I have searched the existing issues

This issue exists in the latest npm version

• I am using the latest npm

This is not just a request to bump a dependency for a CVE

• This is not solely a request to bump a dependency for a CVE

Current Behavior

In a workspace project using install-strategy=linked, after a normal install, npm install --workspaces=false and npm install -w <ws> --include-workspace-root both exit 1 with npm error invalid filterNode: outside idealTree/actualTree. npm install -w <ws> (without --include-workspace-root) works. The hoisted strategy handles all three without error.

Expected Behavior

--workspaces=false and -w <ws> --include-workspace-root should succeed under the linked strategy, as they do under hoisted.

Steps To Reproduce

cd "$(mktemp -d)"
echo 'install-strategy=linked' > .npmrc
cat > package.json <<'EOF'
{ "name": "root", "version": "1.0.0", "workspaces": ["packages/*"],
  "dependencies": { "minimatch": "3.0.4" } }
EOF
mkdir -p packages/a
echo '{ "name": "a", "version": "1.0.0", "dependencies": { "rimraf": "3.0.2" } }' > packages/a/package.json
npm install >/dev/null

npm install --workspaces=false              # -> exit 1: invalid filterNode: outside idealTree/actualTree
npm install -w a --include-workspace-root   # -> exit 1: same error
# hoisted: both exit 0

Environment

• npm: 12.0.0-pre.1 (latest)
• Node.js: v24.17.0
• OS Name: macOS (Darwin 25.5.0)
• System Model Name: MacBook (arm64)
• npm config:

install-strategy=linked