Node.js v23.2.0: Breakpoints not binding in VS Code debugger

[carlmattsimpao]

Version

v23.2.0

Platform

Microsoft Windows NT 10.0.19045.0 x64

Subsystem

Node.js Debugger (V8 Inspector)

What steps will reproduce the bug?

Install Node.js v23.2.0

Create a simple JavaScript file:

test() {
    console.log("test");
    console.log("test2");
}
test();

• Set breakpoints in VS Code
• Start debugging session using VS Code's built-in JavaScript debugger
• Observe that breakpoints are not hit

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

Reproduces 100% of the time with Node.js v23.2.0. Issue does not occur with v23.1.0.

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

Debugger should pause execution at set breakpoints, allowing inspection of program state.

What do you see instead?

Program runs without stopping at breakpoints. Breakpoints appear hollow/unfilled in VS Code, indicating they are not binding to the code.

Additional information

• Downgrading to Node.js v23.1.0 resolves the issue
• Using standard VS Code debugging configuration:

{
    "type": "node",
    "request": "launch",
    "name": "Debug Program",
    "skipFiles": ["<node_internals>/**"],
    "program": "${workspaceFolder}/test.js"
}

VSCode:

Version: 1.95.3 (user setup)
Commit: f1a4fb101478ce6ec82fe9627c43efbf9e98c813
Date: 2024-11-13T14:50:04.152Z
Electron: 32.2.1
ElectronBuildId: 10427718
Chromium: 128.0.6613.186
Node.js: 20.18.0
V8: 12.8.374.38-electron.0
OS: Windows_NT x64 10.0.19045

[ksn5]

+1

[korodarn]

I experienced the same behavior in 23.3.0 as well.

[connor4312]

Looks like Node 23 no longer can enumerate named pipes on Windows which causes this:

PS C:\Users\conno> fnm use 22
Using Node v22.6.0
PS C:\Users\conno> node
Welcome to Node.js v22.6.0.
Type ".help" for more information.
> fs.readdirSync('\\\\.\\pipe').length
838

PS C:\Users\conno> fnm use 23
Using Node v23.3.0
PS C:\Users\conno> node
Welcome to Node.js v23.3.0.
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'
}

Seems to have happened in 23.2, 23.1 works fine. I don't see any suspicious changelog entries for this, just #55527 from @rvagg. Maybe something went wrong in the revert? 🤔

We use this check to detect if the pipe to connect to the debugger is still available when we're operating in the synchronous debug bootloader; 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.

[purnay]

+1

[connor4312]

Made a more specific issue for the underlying bug: #56002