VSCode executes files opened from processes debugged by cppvsdbg in node.js

[sadan4]

Environment

• OS and version: Windows 22H2 (OS Build 19045.2006)
• VS Code: 1.100.2
• C/C++ extension: 1.25.3
• OS and version of remote machine (if applicable): N/A
• GDB / LLDB version: N/A

Bug Summary and Steps to Reproduce

Bug Summary:
If a process debugged by cppvsdbg attempts to launch a file in its default application, and said application is vscode, vscode will execute the file in Node.js

Steps to reproduce:

1. Using this repo https://github.com/sadan4/vscppdbg-repro
2. Make sure VS Code is your default application for opening text files
3. Change the path in main.c for your environment
4. Compile main.c. I've reproduced this with gcc main.c and clang main.c -lShell32.
5. Start the debugging session
6. Observe in the external console that the file is executed as JavaScript and not opened in VS Code

Video (taken in a VM):

2025-05-27.19-55-33.mov

Notes:

• I cannot reproduce this with gdb at all
• When I attempted to reproduce this in a VM, I was not able to get the output from Node.js 100% of the time, however it never opened the file properly
• I have reproduced this bug with many types of files (c, txt, js, css, ...)
• The contents of the opened file do not matter; it will throw a syntax error if it's not valid JavaScript
• If the file has no default association and Windows prompts for one to be selected, it will work properly
• any form of opening the file results in this error eg: calling out powershell to open the file

Debugger Configurations

https://github.com/sadan4/vscppdbg-repro/blob/master/.vscode/launch.json

Debugger Logs

Hello World
for some reason, vscode runs this as a js file in node only when lanuched from a process being debugged by cppvsdbg
some info:
ARGV:  [
  'C:\\Users\\user\\AppData\\Local\\Programs\\Microsoft VS Code\\Code.exe',
  'C:\\repro\\file.txt'
]
require.main:  {
  id: '.',
  path: 'C:\\repro',
  exports: {},
  filename: 'C:\\repro\\file.txt',
  loaded: false,
  children: [],
  paths: [ 'C:\\repro\\node_modules' ],
  [Symbol(kIsMainSymbol)]: true,
  [Symbol(kIsCachedByESMLoader)]: false,
  [Symbol(kIsExecuting)]: true
}
 
C:\repro\file.txt:3
throw new Error();
^
 
Error
    at Object.<anonymous> (C:\repro\file.txt:3:7)
    at Module._compile (node:internal/modules/cjs/loader:1544:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1629:10)
    at Module.load (node:internal/modules/cjs/loader:1282:32)
    at Module._load (node:internal/modules/cjs/loader:1103:12)
    at c._load (node:electron/js2c/node_init:2:16955)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:179:12)
    at node:internal/main/run_main_module:28:49
 
Node.js v20.19.0

Other Extensions

I only have C/C++ and C/C++ Themes installed

Additional Information

No response

[sean-mcmanus]

@sadan4 Our debugger contact says this is not a debugger bug and "is due to the behavior of the terminal that is being used when ShellExecuteW is called which causes VS Code to run the file".

[gregg-miskelly]

In case a longer explanation is helpful -- What your code is trying to do is launch an instance of VS Code (Code.exe) from within the context of the internal or external terminal. There is something in code.exe that detects this scenario and thinks it is being launched to run node code. If your goal is to show VS Code in this scenario, I am not totally sure what VS Code's logic is here, so you might need to debug it. One possibility is that there are detecting an environment variable, if so, you could clear it before calling ShellExecute.

[sadan4]

For anyone coming across this, I was able to get around this by removing ELECTRON_RUN_AS_NODE from the environment