Repro: rspack NativeWatcher concurrent &mut race crash (<= 2.1.4, macOS FSEvents use-after-free)

repro-native-watcher-crash.js

// Repro for a concurrent `&mut` race in NativeWatcher (rspack <= 2.1.4).
//
// Usage:
//   npm i @rspack/binding@2.1.4
//   node repro-native-watcher-crash.js
//
// On macOS the process dies within a few iterations, typically with:
//   NSInvalidArgumentException: -[OS_os_log addObject:]: unrecognized selector
// (use-after-free on notify's FSEvents watched-paths CFMutableArray).
// Debug builds instead hit tokio's `!curr.is_join_waker_set()` assertion.
const fs = require("node:fs");
const os = require("node:os");
const path = require("node:path");

const binding = require("@rspack/binding");

const ITERATIONS = 30;
const WATCHES_PER_ITERATION = 5;
const FILE_COUNT = 400;

const dir = fs.mkdtempSync(path.join(os.tmpdir(), "rspack-native-watcher-"));
const files = [];
const dirs = [dir];
for (let i = 0; i < FILE_COUNT; i++) {
  const sub = path.join(dir, `sub${i % 20}`);
  fs.mkdirSync(sub, { recursive: true });
  const file = path.join(sub, `f${i}.js`);
  fs.writeFileSync(file, `module.exports = ${i};`);
  files.push(file);
  if (!dirs.includes(sub)) dirs.push(sub);
}

const startWatch = (watcher) => {
  watcher.watch(
    [files, []],
    [dirs, []],
    [[], []],
    BigInt(Date.now()),
    () => {},
    () => {},
  );
};

(async () => {
  console.log(`pid: ${process.pid}`);
  for (let i = 0; i < ITERATIONS; i++) {
    const watcher = new binding.NativeWatcher({ aggregateTimeout: 1 });
    for (let j = 0; j < WATCHES_PER_ITERATION; j++) startWatch(watcher);
    await watcher.close();
    try {
      startWatch(watcher);
    } catch (e) {
      /* expected: has been closed */
    }
    console.log(`iteration ${i + 1}/${ITERATIONS} survived`);
  }
  console.log("ALL ITERATIONS SURVIVED (no crash)");
  fs.rmSync(dir, { recursive: true, force: true });
})();