Javascript debugger does not connect to headless instance

Environment (please complete the following information):

• OS: MacOS 12.1 (M1 Mac Mini)
• Extension version: 1.4.5

Describe the bug:

The Javascript debugger does not connect to headless Edge instance.

Repro steps:

• Launch web server with npm in debug shell
• Launch edge devtools in headless mode with screencast
• Debugger does not attach and breakpoints remain disabled

Expected behavior:

Debugger should attach to the instance of Edge running headless with screencast, just like it does with a separate Edge window.

Additional context:

I am attempting to launch my app using a compound configuration in launch.json (see below for specifics). If I launch Edge using type: pwa-msedge then my web server debugger attaches just fine and breakpoints work as expected. I can also attach the Edge DevTools in VSCode to that running instance.

However, I would ideally like a completely unified dev experience, with code, dev tools, and browser embedded within a single VSCode window. I can launch an independent, headless instance of Edge with screencast in my VSCode window, but launching the DevTools directly in this manner does not connect to my app’s debugger/breakpoints.

Snippets from launch.json

"configurations": [
    {
      "name": "Open App",
      "request": "launch",
      "type": "pwa-msedge",
      "url": "http://localhost:3000",
      "webRoot": "${workspaceFolder}",
    },
    {
      "name": "Open App (Headless)",
      "request": "launch",
      "type": "vscode-edge-devtools.debug",
      "url": "http://localhost:3000",
      "webRoot": "${workspaceFolder}",
    },
    {
      "name": "Start App",
      "command": "npm run start",
      "request": "launch",
      "type": "node-terminal"
    }
],
"compounds": [
    {
      "name": "Debug App (Works)",
      "configurations": ["Start App", "Open App"]
    },
    {
      "name": "Debug App (Does not work)",
      "configurations": ["Start App", "Open App (Headless)"]
    }
]

[codepo8]

You can add the headless option to your launch.json and it works (at least here right now). Notice the runtimeArgs.

{
    "version": "0.2.0",
    "configurations": [
        {
            "type": "pwa-msedge",
            "request": "launch",
            "name": "webdebug",
            "url": "http://localhost:8080",
            "webRoot": "${workspaceFolder}",
            "runtimeExecutable": "stable",
            "runtimeArgs": ["--headless"]
        }
    ]
}

[5hee75]

You can add the headless option to your launch.json and it works (at least here right now). Notice the runtimeArgs.

This is nice workaround for the time being. If I include both the headless pwa-msedge as well as the vscode-edge-devtools.debug then it effectively behaves as desired. Thanks!