DAP ContinuedEvent with allThreadsContinued=true causes selected debug session to change

[DanTup]

When sending a ContinuedEvent with allThreadsContinued=true, the selected debug session resets to the first one. This does not happen without allThreadsContinued=true.

To repro:

• Clone MockDebug
• Add response.body.supportsRestartRequest = true; in initializeRequest
• Implement a restartRequest that sends a ContinuedEvent with allThreadsContinued=true:

  protected async restartRequest(response: DebugProtocol.RestartResponse, args: DebugProtocol.RestartArguments) {
  	this.sendResponse(response);
  	this.sendEvent(new ContinuedEvent(0, true));
  }

• Run the project
• Create a second launch config:

  "configurations": [
  	{
  		"type": "mock",
  		"request": "launch",
  		"name": "Debug readme.md 1",
  		"program": "${workspaceFolder}/readme.md",
  		"stopOnEntry": true,
  		"trace": false
  	},
  	{
  		"type": "mock",
  		"request": "launch",
  		"name": "Debug readme.md 2",
  		"program": "${workspaceFolder}/readme.md",
  		"stopOnEntry": true,
  		"trace": false
  	}
  ]

• Start both launch configurations (this can be done one at a time)
• Select the second debug session in the debug toolbar
• Click the Restart button
• Note that the dropdown has reverted to the first session

[isidorn]

@DanTup I pushed a potential fix for this. Can you please try it out with VS Code insiders from tomorrow? thank you very much!

[DanTup]

@isidorn did the Insiders build today get delayed? I still see the issue, but it looks like current insiders is still only 7c25c17 from around 36 hours ago.

[isidorn]

@DanTup I am not sure if that insiders had my fix. If it is not a problem can you try it with today's insiders (which I am sure has my change)?

[DanTup]

@isidorn sorry for the delay, I've been OOO. Unfortunately this still repros in:

Version: 1.60.0-insider
Commit: 44568e5947efa4811419e529e80fb14b7554cf61
Date: 2021-08-23T10:42:53.526Z
Electron: 13.1.8
Chrome: 91.0.4472.164
Node.js: 14.16.0
V8: 9.1.269.39-electron.0
OS: Darwin x64 20.6.0

[isidorn]

No problem, let's reopen and I can investigate

[isidorn]

I can reproduce following your steps. And I actually think this behaviour is fine.
The problem is that Season A sends a continued event and then we pass focus to session B. This is expected, if season A was stopped in the meantime we would not pass focus. Moving out of milestone since we will not change anything here this week, and assigning to @roblourens since he now owns Debug UI.

Code pointer for focus passing https://github.com/microsoft/vscode/blob/main/src/vs/workbench/contrib/debug/browser/debugSession.ts#L1002

[DanTup]

I'm not sure I understand. The behaviour differs between allThreadsContinued=true and allThreadsContinued=false even though that doesn't make any difference to any behaviour here. Also some of the debug toolbar functionality (restart, stop, hot reload) does not require a stopped session, so changing the active session when using them based on whether the session was stopped or not seems odd.