Awaiting a Promise between creating a stream and consuming a stream causes Node to crash with code 13

[penalosa]

Version

v20.4.0

Platform

Darwin 22.1.0 Darwin Kernel Version 22.1.0: Sun Oct 9 20:15:09 PDT 2022; root:xnu-8792.41.9~2/RELEASE_ARM64_T6000 arm64 arm Darwin

Subsystem

No response

What steps will reproduce the bug?

Run:

import { Blob } from "node:buffer";

const stream = new Blob(["Hello world"]).stream();

await Promise.resolve();

await stream.pipeTo(new WritableStream());
console.log("Done");

with node. The process will exit with code 13

How often does it reproduce? Is there a required condition?

Always reproduces when the line await Promise.resolve(); is included (or awaiting any promise). If that line is commented out the program prints "Done"

What is the expected behavior? Why is that the expected behavior?

I expect the sample program to run to completion and print "Done", as it does in node v20.3.1

What do you see instead?

Node exiting with code 13:

> node sample.mjs

> echo $?
13

Additional information

No response

[bnoordhuis]

It's mentioned in the documentation on node's exit codes:

• 13 Unfinished Top-Level Await: await was used outside of a function
  in the top-level code, but the passed Promise never resolved.

[bnoordhuis]

I expect the sample program to run to completion and print "Done", as it does in node v20.3.1

Sorry, I should have mentioned the old behavior was probably a bug. The new behavior is the expected behavior.

[bnoordhuis]

On second thought, I think this is indeed a bug, or at least an unintentional change in behavior introduced in f9c0d5a, cc @debadree25.

[debadree25]

hello!

hmm this does look like a bug so in my PR fixing hanging promises thing i am enqueing data during the microtask phase maybe thats causing some weird mixup in the event loop, I am investigating this! in the meanwhile do you think i should make a revert? in case this is breaking things?

[bricss]

I have an issue with blobs as well that started with Node v20.4.0, but it's related to blob to stream conversion and http2 client transfer, which is leading to readable stream to never close, hanging connection forever ♾️
I will file a separate issue with reproduction example a bit later ⌚
But atm it's reproducible by simply running tests for this npm package 📦 https://www.npmjs.com/package/rekwest

[bricss]

Here we go -> #48685

[asamuzaK]

Similar bug with fetch.

const file = new Blob(['<svg></svg>'], {
  type: 'image/svg+xml'
});
const url = URL.createObjectURL(file);
const res = await fetch(url);
const blob = await res.blob(); // does not resolve
console.log(blob.size); // nothing logged

It was working fine until v20.3.1.

There is also #48157 for blob related fixes.

[bricss]

ISTM, that #48232 fixed hanging promises, but causing hanging streams right now 🤔
And it might be missing pending.resolve() inside of queueMicrotask() 🔬

[debadree25]

And it might be missing pending.resolve() inside of queueMicrotask() 🔬

But it does call promise resolve and reject inside the readNext fn

Nonetheless sorry for the delay I shall get to investigating it by tomorrow!

[bricss]

It's highly likely that manual backpressure check results in a deadlock after stream drain 🙄

[debadree25]

Okay adding the promise resolve indeed fixes things i am opening a PR, in the process of adding tests

[debadree25]

Okay on testing, it breaks existing tests 🥲 guess would be best to revert it for now i think

[bricss]

Try to revert it and then add queueMicrotask() w/o manual backpressure check 💡

[debadree25]

without the backpressure check memory leak we get memory leak, nonetheless let me try until to night else reverting the full PR