Using "args" in launch.json for an attach request reports an error

Describe the bug

When trying to attach the debugger to a flutter app I get the error message:

There are multiple observatory ports available.
Rerun this command with one of the following passed in as the appId:

  flutter attach --app-id com.example.myApp
  flutter attach --app-id com.example.myApp (2)

However, there is no configuration option available for type dart in the launch.json for me to be able to specify app-id

My launch.json looks like this:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "debug app",
            "request": "attach",
            "type": "dart",
            "deviceId": "51ABDF9C-C54D-4811-BBDA-E733639AEC51",
        },
    ]
}

To Reproduce Steps to reproduce the behavior:

1. Run an app in the terminal with flutter run
2. Run the debug app launch config specified above.

I’ve also tried not launching with flutter run by just tapping on the app in the emulator and then trying to attach but the same problem occurs.

Expected behavior

I expected to be able to attach to the running process.

Versions (please complete the following information):

• VS Code version: 1.57.1
• Dart extension version: 3.23.1
• Dart/Flutter SDK version: Flutter 2.2.1, Dart 2.13.1

[ksilz]

I had the same thing happening when debugging a Flutter app on iOS in IntelliJ. Adding --app-id com.yourhomeingoodhands.mobile.yhigh in the “Additional attach args” field of the “Run/Debug Configuration” of my Flutter app fixed it. That was suggested by somebody in the forum.

[DanTup]

Thanks - I suspected that might be the case as I was updating the title - if I remember correctly they have their own definitions. There’s probably not been much reason to use args in attach before this, so may have been left off intentionally, but this seems like good reason to change it - we shouldn’t report errors on settings that actually change behaviour.

Thanks!