Bug: Missing stdio pipes with node:child_process

[marvinhagemeister]

Tried the current state of running playwright in Deno (see #16899) and ran into an issue regarding the pipes set up for node:child_process.spawn(). The launcher code can be found here https://github.com/microsoft/playwright/blob/main/packages/playwright-core/src/utils/processLauncher.ts#L133

They expect to receive 5 streams to be set up, but we only set up the first three. I created a minimal reproduction out of that:

Steps to reproduce

1. Create file main.mjs with these contents

import cp from "node:child_process";
import process from "node:process";

if (import.meta.url.endsWith("main.mjs")) {
  const child = cp.spawn(process.execPath, [import.meta.url], {
    stdio: ["ignore", "pipe", "pipe", "pipe", "pipe"],
  });

  console.assert(
    child.stdio.length === 5,
    `Expected stdio length to equal 5 but got ${child.stdio.length}`
  );
}

2. Run DENO_FUTURE=1 deno run -A main.mjs

Can also be run in Node for comparison node main.mjs

Version: Deno 1.42.4 (git 5294885 2024-04-24)

[cowboyd]

@marvinhagemeister The docs only very briefly mention the ability to open other file descriptors https://nodejs.org/api/child_process.html#optionsstdio Is there any explainer anywhere on how they should behave?

[marvinhagemeister]

I'm not aware of any explainer. I don't know how they're supposed to work either. One would probably look at the Node source code to get an answer to that.