[BUG] `npx` always re-reifies directory/`file:` specs even when already cached

[manzoorwanijk]

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

Current Behavior

Every invocation of npx <cmd> that resolves to a local directory (file: spec) triggers a full reify() cycle, even when the package is already installed in the npx cache. Registry packages correctly skip the reify on subsequent runs.

This happens regardless of install-strategy — both hoisted and linked are affected.

Expected Behavior

npx should detect that a directory spec is already installed in the npx cache and skip the reify step when the package is unchanged, just as it does for registry packages.

Steps To Reproduce

rm -rf /tmp/host-app ~/.npm/_npx
mkdir -p /tmp/host-app/dist

cat > /tmp/host-app/package.json << 'EOF'
{
  "name": "host-app",
  "version": "1.0.0",
  "bin": { "my-tool": "dist/main.js" }
}
EOF

cat > /tmp/host-app/dist/main.js << 'EOF'
#!/usr/bin/env node
console.log('my-tool ran')
EOF
chmod +x /tmp/host-app/dist/main.js

cd /tmp/host-app
npm install
npx my-tool        # run 1 — reifies (expected, cold cache)
npx my-tool        # run 2 — reifies again (unexpected)
npx my-tool        # run 3 — reifies again (unexpected)

Contrast with a registry package:

rm -rf ~/.npm/_npx
npx cowsay@1.6.0 hello   # run 1 — reifies (expected)
npx cowsay@1.6.0 hello   # run 2 — skips reify (cache hit)

Confirmed with debug logging

Adding console.error('DEBUG add:', JSON.stringify(add)) before the if (add.length) check in libnpmexec/lib/index.js:

# directory spec — add is always non-empty
Run 1: DEBUG add: ["file:/private/tmp/host-app"]
Run 2: DEBUG add: ["file:/private/tmp/host-app"]  ← should be []

# registry spec — add is empty on cache hit
Run 1: DEBUG add: ["cowsay@1.6.0"]
Run 2: DEBUG add: []                              ← correctly cached

Environment

• npm: 11.12.1
• Node.js: v24.14.0
• OS Name: macOS (Darwin 25.4.0)

Root Cause Analysis

In libnpmexec/lib/index.js, missingFromTree() has an early return for directory specs that bypasses the cache check:

if (spec.type === 'directory') {
  return { manifest }
}

Returning { manifest } (without a node) signals "not in tree — needs install." This causes the caller to unconditionally push the package onto the add list and call npxArb.reify().

For registry specs, the function instead walks the tree looking for a matching resolved:

for (const node of nodesByManifest) {
  if (node.package.resolved === manifest._resolved) {
    return { node }  // found in cache — no install needed
  }
}

Directory specs skip this check entirely, so the npx cache is never consulted.

Surfaced while investigating #9210.