nodejs/deps/v8/test/mjsunit/harmony/weakrefs/cleanup-proxy-from-different-realm.js

// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Flags: --expose-gc --noincremental-marking

(async function () {

  let r = Realm.create();

  let cleanup = Realm.eval(r, "var stored_global; let cleanup = new Proxy(function() { stored_global = globalThis;}, {}); cleanup");
  let realm_global_this = Realm.eval(r, "globalThis");

  let fg = new FinalizationRegistry(cleanup);

  // Create an object and register it in the FinalizationRegistry. The object needs
  // to be inside a closure so that we can reliably kill them!
  let weak_cell;

  (function () {
    let object = {};
    fg.register(object, "holdings");

    // object goes out of scope.
  })();

  // We need to invoke GC asynchronously and wait for it to finish, so that
  // it doesn't need to scan the stack. Otherwise, the objects may not be
  // reclaimed because of conservative stack scanning and the test may not
  // work as intended.
  await gc({ type: 'major', execution: 'async' });

  // Assert that the cleanup function was called in its Realm.
  let timeout_func = function () {
    let stored_global = Realm.eval(r, "stored_global;");
    assertNotEquals(stored_global, globalThis);
    assertEquals(stored_global, realm_global_this);
  }

  setTimeout(timeout_func, 0);

})();