Promise returned from sync `dispose` method should not be awaited when disposing an asyc-disposable

[JLHwung]

🔎 Search Terms

using

🕗 Version & Regression Information

I assume it is in every version that using has been implemented

⏯ Playground Link

https://www.typescriptlang.org/play?ts=5.5.0-dev.20240404#code/BQQwzgngdgxgBMAlHAvAPjgbwFAwPZRgAucANngOapwDaAugNzbZxz6EkAOATngLYBLMAFMAIkM54R1KMIDucAAq9BI4MG7CweUgDdhAGjgB9ZOiwtWcEUQAqAvsLwBXIurMYcVq+QoA6TmcwAAtgACIIOAATCSlhOB5+IXiAIzwoiDDEJm9WTW09YSQcqwBfIwAGbMtS6ssvKxA5EAESIIEoKgAPagbvcGh4GgBlCD400j8B2HEwSWkUOFHxnT8AMzxucOWJqcgZ2JEsuiQLXJ9KAKDQsJ7pmFn51PTM6vPyy1ZSktYmlrawB0qJFFn0rCMxrsYnM4tQdqsNlswvDJtCnsdTmDvL4riFwpE0bC0hksj9cpoiM5uFAEipko84mSvgZPnBvjVmKwcYE8WFia8mJY-q1aUkRAyRILWOwCsI-L5gL5qrVikA

💻 Code

(async () => {
  const log = [];

  const promiseDispose = new Promise((resolve, _) => {
    setTimeout(() => {
      log.push("y dispose promise body");
      resolve();
    }, 0);
  });

  {
    await using x = {
      async [Symbol.asyncDispose = Symbol.for("Symbol.asyncDispose")]() {
        log.push("x asyncDispose body");
      },
    };
    await using y = {
      [Symbol.dispose = Symbol.for("Symbol.dispose")]() {
        log.push("y dispose body");
        return promiseDispose;
      },
    };
  }

  log.push("body");

  await promiseDispose;

  console.log(log);
})();

🙁 Actual behavior

It logs ["y dispose body", "y dispose promise body", "x asyncDispose body", "body"]

🙂 Expected behavior

It should log ["y dispose body", "x asyncDispose body", "body", "y dispose promise body"].

The "y dispose promise body" should be printed in the next event cycle, however it is printed before x asyncDispose body because the promise is awaited when disposing y.

Additional information about the issue

Per 7.5.6 GetDisposeMethod

NOTE: This function is not observable to user code. It is used to ensure that a Promise returned from a synchronous dispose method will not be awaited.

cc @rbuckton

[rbuckton]

Thanks, I plan to fix this shortly along with several other small normative changes up for discussion at next week's TC39 plenary.