Windows: Execa is leaking processes when used with readline

[Ciantic]

Repro is here: https://github.com/Ciantic/execa-readline-problems

There is also a long spanning discussion because it leads to snowpack leaking processes in Windows: https://www.pika.dev/npm/snowpack/discuss/295

It seems like the cleanup is not working correctly when readline is used. Also I think there is some race condition here, because I have managed to make scripts where the execa cleanup happens sometimes, but sometimes not. So it's not deterministic.

node --version: v12.18.0

[sindresorhus]

Can you check whether the problem is also reproducible on Node.js 14? I don't have a Windows VM right now, so I cannot test.

Can you also try replacing const myProcess = execa('tsc --noEmit --watch', {shell: true, cleanup: true}); with const myProcess = execa.command('tsc --noEmit --watch', {cleanup: true});?

[MatejBransky]

I can't reproduce it with PowerShell (v5.1.19041.1) Node.js v12.14.0 on Windows 10 (version 2004 OS build 19041.264). In this environment it succesfully killed the process.

[Ciantic]

@MatejBransky interesting. Notice that for me it has behaved like this: It worked e.g. 10 times a row and then it stopped working for a while etc.

That is the reason I suspect there is race condition.

[MatejBransky]

@Ciantic Ok and how to reproduce it? I've tried it multiple times and it still worked.

[Ciantic]

@MatejBransky if there is a race condition, it might not be reproducible on all systems and setups. Because something is delayed just enough in my machine, or works faster in yours.

[Ciantic]

@MatejBransky If it works for you, you shouldn't waste more time with this. I have to investigate further if it's reproducible only on my setup for some reason. You can see from here: https://www.pika.dev/npm/snowpack/discuss/295 it's been a painful to debug.

[MatejBransky]

@Ciantic I've come here from your pika discussion and I would like to help but unfortunately I don't know how. 😒

[Ciantic]

I tested this in the VM. The Windows Sandbox with Windows 10 2004. It's still reproducible with this setup, so yes I would conclude it's broken somehow.

Tested node versions:
v12.18.0 32bit
v14.4.0 32bit

I updated my repository with repro, nothing that changes the behavior.

[ManiacDC]

I can also reproduce this, Windows 10 1909
node v12.14.1

Tried from both bash and powershell

[ManiacDC]

Worth noting, I can't reproduce this using the same example code with execa 1.0.0.

[Ciantic]

It's sometimes not reproducible, so if you managed to reproduce it once, it might still be reproducible.

[ehmicky]

More information in #433 (which seems to be a duplicate issue).

Could you try to pass the windowsHide: false option to Execa and see if this solves the problem?

[ManiacDC]

I just tested this specific issue with windowsHide: false and it fixed this one too, so #433 and this issue do appear to be duplicates.

[ehmicky]

Thanks for checking this out @ManiacDC! Closing this issue as duplicate then.