node/test/parallel/test-vm-module-after-evaluate.js

// Flags: --experimental-vm-modules
'use strict';

// https://github.com/nodejs/node/issues/59541
//
// Promises created in a context using microtaskMode: "aferEvaluate" (meaning it
// has its own microtask queue), when resolved in the surrounding context, will
// schedule a task back onto the inner context queue.

const common = require('../common');
const vm = require('vm');

const microtaskMode = 'afterEvaluate';

(async () => {
  const mustNotCall1 = common.mustNotCall();
  const mustNotCall2 = common.mustNotCall();
  const mustCall1 = common.mustCall();

  const inner = {};

  const context = vm.createContext({ inner }, { microtaskMode });

  const module = new vm.SourceTextModule(
    'inner.promise = Promise.resolve();',
    { context },
  );

  await module.link(mustNotCall1);
  await module.evaluate();

  // Prior to the fix for Issue 59541, the next statement was never executed.
  mustCall1();

  await inner.promise;

  // This is expected: the await statement above enqueues a (thenable job) task
  // onto the inner context microtask queue, but it will not be checkpointed,
  // therefore we never make progress.
  mustNotCall2();
})().then(common.mustNotCall('never settling promise expected'));

(async () => {
  const mustNotCall1 = common.mustNotCall();
  const mustCall1 = common.mustCall();
  const mustCall2 = common.mustCall();
  const mustCall3 = common.mustCall();

  const inner = {};

  const context = vm.createContext({ inner }, { microtaskMode });

  const module = new vm.SourceTextModule(
    'inner.promise = Promise.resolve();',
    { context },
  );

  await module.link(mustNotCall1);
  await module.evaluate();
  mustCall1();

  setImmediate(() => {
    mustCall2();
    // This will checkpoint the inner context microtask queue, and allow the
    // promise from the inner context to be resolved in the outer context.
    module.evaluate();
  });

  await inner.promise;
  mustCall3();
})().then(common.mustCall());