Permission Inheritance (`--allow-worker` inherits parent permissions)

What is the problem this feature will solve?

Today, --allow-worker is an all-or-nothing escape hatch. The docs state this explicitly as a constraint: "The model does not inherit to a worker thread." This means any code running inside a worker can access the filesystem, spawn child processes, and do anything else without restriction, regardless of what the main thread was allowed to do.

This defeats the purpose of the permission model for any application that uses workers, which is most CPU-intensive Node.js applications.

What is the feature you are proposing to solve the problem?

When the main thread creates a Worker, the worker inherits a snapshot of the parent thread's permission state at the time of creation. The worker starts with exactly the same permissions as its parent — no more, no less.

// Main thread: started with --permission --allow-fs-read=/app --allow-worker
const { Worker } = require('node:worker_threads');
 
const worker = new Worker('./task.js');
// task.js runs with fs.read granted for /app only
// task.js cannot spawn child processes (parent couldn't either)
// task.js cannot read /etc, /home, or anything outside /app

This might be a breaking change. We could then add a --allow-inherit-worker to achieve the same.

What alternatives have you considered?

No response

まず、現在の --allow-worker の動作、権限モデルのドキュメント、Worker の作成セマンティクスを確認します。提案されている breaking change または --allow-inherit-worker の代替案を含め、Worker が親の権限スナップショットをどのように継承すべきかを定義して検証します。動作と互換性に関する選択が文書化され、テストでカバーされていれば完了です。