Node 22 broke `readdir` on Windows UNC paths

[felipecrs]

Version

22.15.0

Platform

Microsoft Windows NT 10.0.26100.0 x64

Subsystem

fs

What steps will reproduce the bug?

~\repos\clipboard-sync v0.16.2 ❯ volta run --node 20 node --eval 'console.log(require("fs").readdirSync("S:\\\\"))'  20:09:08 
[ 'FELIPE-DESKTOP.is-receiving.txt' ]

~\repos\clipboard-sync v0.16.2 ❯ volta run --node 22 node --eval 'console.log(require("fs").readdirSync("S:\\\\"))'  20:09:58 
node:fs:1584
  const result = binding.readdir(
                         ^

Error: ENOENT: no such file or directory, scandir 'S:\\'
    at Object.readdirSync (node:fs:1584:26)
    at [eval]:1:27
    at runScriptInThisContext (node:internal/vm:209:10)
    at node:internal/process/execution:449:12
    at [eval]-wrapper:6:24
    at runScriptInContext (node:internal/process/execution:447:60)
    at evalFunction (node:internal/process/execution:87:30)
    at evalScript (node:internal/process/execution:99:3)
    at node:internal/main/eval_string:74:3 {
  errno: -4058,
  code: 'ENOENT',
  syscall: 'scandir',
  path: 'S:\\\\'
}

Node.js v22.15.0

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

Always.

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

To work, like it always used to.

What do you see instead?

ENOENT.

Additional information

I noticed this when upgraded my application from Electron 34 to 35, which also upgraded Node from 20 to 22. Maybe this is related to:

• try catch not work if path include unicode #51802

Whatever was done there may have broken other cases.

[joyeecheung]

I think it might have been another regression from #52135 cc @nodejs/platform-windows @anonrig

[felipecrs]

Just FYI this issue continues to happen with Node 22.17.1 and 24.4.1.

[felipecrs]

@anonrig, would you please look at this? It seems to be a regression caused by your PR.

[anonrig]

@anonrig, would you please look at this? It seems to be a regression caused by your PR.

I don't use Windows on a daily basis. Can you share a repro with no dependencies?

I can probably look next week but this is an open project. All contributions are welcome, including yours.

[felipecrs]

Can you share a repro with no dependencies?

You need a network drive mounted to reproduce the issue. The easiest way I found to reproduce it is:

1. PowerShell: winget install rclone.rclone

2. Restart Terminal/PowerShell

3. PowerShell: rclone mount :memory: N: --network-mode

4. Leave it running and open another PowerShell

5. PowerShell: New-Item -Type File N:\file.txt

6. Confirm it works with Node.js 20:

   $ node --version
   v20.19.4
   
   $ node --eval 'console.log(require("fs").readdirSync("N:\\"))'
   [ 'file.txt' ]

7. Confirm the bug with newer Node.js versions:

   $ node --version
   v20.19.4
   
   $ node --eval 'console.log(require("fs").readdirSync("N:\\"))'
   node:fs:1583
     const result = binding.readdir(
                            ^
   
   Error: ENOENT: no such file or directory, scandir 'N:\\'
       at Object.readdirSync (node:fs:1583:26)
       at [eval]:1:27
       at runScriptInThisContext (node:internal/vm:209:10)
       at node:internal/process/execution:446:12
       at [eval]-wrapper:6:24
       at runScriptInContext (node:internal/process/execution:444:60)
       at evalFunction (node:internal/process/execution:279:30)
       at evalTypeScript (node:internal/process/execution:291:3)
       at node:internal/main/eval_string:74:3 {
     errno: -4058,
     code: 'ENOENT',
     syscall: 'scandir',
     path: 'N:\\\\'
   }
   
   Node.js v22.19.

[felipecrs]

I can probably look next week but this is an open project. All contributions are welcome, including yours.

I know, but there's no one better to investigate the issue than who caused it (assuming it was really you). 😅

PS: I already tried months ago.