[Feature] Shell Implementation should accept NUL (nul) as null device for redirection

[jeffrson]

• I'd be willing to implement this feature (contributing guide)
• This feature is important to have in this repository; a contrib plugin wouldn't do

Describe the user story

yarn has a "bash like" internal shell for scripts in package.json. This shell tries to be "cross platform". As such it handles "/dev/null" to ignore standard output of commands. However, on Windows, /dev/null does not exist.
There is a need of Windows only scripts: Since there's no external or builtin cp command, "xcopy" or "cmd /c copy" must be used on Windows. It looks weird to redirect its output to /dev/null in such circumstances. Also there's no benefit (in terms of crossplatform), since the script will not work on Linux or Mac anyway.

Describe the solution you'd like

The integrated shell should use "NUL" (case independent) as an alias to /dev/null, and treat it alike.

Describe the drawbacks of your solution

There would be no way to redirect standard output/error to a file called "nul" on Linux/Mac.

Describe alternatives you've considered

None.

[arcanis]

Not sure I see the benefit? Instead of having an unexpected syntax for one system, this would just make an unexpected syntax for all systems. Additionally, we already implement the : builtin which kinda does this already, if really needed.

[jeffrson]

There's no unexpected syntax on other systems - they may use /dev/null as before.

Additionally, the trouble with NUL (as Windows users would normally use) is, that yarn (via node) creates a file called "NUL", which is cumbersome to get rid of (especially after yarn workspace foreach). I assumed this to be a bug in node, but it seems it aint: nodejs/node#33829

I'm not sure, how ":" would help here.

[yarnbot]

Hi! 👋

It seems like this issue as been marked as probably resolved, or missing important information blocking its progression. As a result, it'll be closed in a few days unless a maintainer explicitly vouches for it.

[jeffrson]

It's not resolved - and feedback has been sent.

I still find it helpful to get an alias (not a platform specific replacement): this is more readable for Windows people (they might not understand why there should be /dev/null) and it would prevent creating a file NUL, which is somewhat hard to handle.

[arcanis]

I'll close this as wontfix, I'm still not sure why | : or > /dev/null are unsuitable.

The NUL problem you're referencing on Windows seems like it'd only happen if you do > NUL in the first place, which I'm not sure why it'd happen given that we don't support that as a special syntax.

Finally, new syntaxes wouldn't be compatible with other package managers so, while it'd be safe to use in most scripts, they wouldn't be safe to use in postinstall scripts. Coupled with the lack of clarity in the use case, that doesn't strike me as a good idea.