Node 23.2 fs lost the ability to enumerate named pipes on Windows

[connor4312]

Version

23.2.0

Platform

Microsoft Windows NT 10.0.22631.0 x64

Subsystem

fs

What steps will reproduce the bug?

This regressed in 23.2:

PS C:\Users\conno> fnm use 23.1
Using Node v23.1.0
PS C:\Users\conno> node
Welcome to Node.js v23.1.0.
Type ".help" for more information.
> fs.readdirSync('\\\\.\\pipe').length
510

PS C:\Users\conno> fnm use 23.2
Using Node v23.2.0
PS C:\Users\conno> node
Welcome to Node.js v23.2.0.
Type ".help" for more information.
> fs.readdirSync('\\\\.\\pipe').length
Uncaught Error: ENOTDIR: not a directory, scandir '\\.\pipe'
    at Object.readdirSync (node:fs:1499:26) {
  errno: -4052,
  code: 'ENOTDIR',
  syscall: 'scandir',
  path: '\\\\.\\pipe'
}

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

100%

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

The contents of \\.\pipe should be able to be read as a directory.

What do you see instead?

ENOTDIR when enumerating \\.\pipe

Additional information

This causes js-debug's debugger to break #55948. There is not really a good workaround.

Windows lacks any kind of API aside from this for checking the existence of a named pipe--as exists / stat actually connects to the pipe--so listing \\.\pipe is a common pattern for Windows applications who need to check (e.g. https://berserkerdotnet.github.io/blog/detecting-namedpipe-exists/)

[Flarna]

bisect a bit on 23 branch and found that commit 038ac01 seems to cause this.
The corresponding commit on main is 7f68e54 from PR #55623.

The diff introduced with above commit is that node:ToNamespacedPath() appended \ before, after the commit it doesn't.
\\\\.\\pipe\\ - works
\\\\.\\pipe - fails

@huseyinacacak-janea any hints how to fix this.