Restarting a Debug Adapter doesn't reset the Visual Studio Interface

[willco007]

1. Create a debug adapter which supports restart by specifying supportsRestartRequest.
2. Stop at a breakpoint such that the Variables and Call Stack interfaces are populated
3. Press the Restart button in Visual Studio Code

Expected:
The Visual Studio Code interface is reset when it gets back the empty response from the Restart request message

Actual:
The Visual Studio Code interface remains stale after getting sent a response from the Restart request.

[willco007]

Since this bug was assigned to @weinand, I would note the restart request documentation is missing detail around what it expects the debuggee to do in this case. Currently we're sending the exited and process events when the app is restarted (along with the expected restart response), but they also don't clear the UI in VS Code.

[weinand]

Most likely a terminate event is missing.

Since supporting the restart request is optional, you don't have to implement it. VS Code will implement "Restart" by stopping the existing session and then starting a new session.

[willco007]

Thanks for the reply! I do understand implementing restart isn't required, I was implementing it for completeness since it exists, but am seeing this unexpected behavior with it.

VS Code doesn't send a terminate request as part of the restart request process. Once I reply to the restart request, VS Code sends no more requests. I did try sending the terminated event after the restart request reply with restart set to yes in the body, but VS Code will completely disconnect the session at that point.

Just looking for guidance on what VS Code expects as part of this handshake or if it's an actual bug in VS Code with the restart request behavior.

[weinand]

I can reproduce the issue with Mock Debug (running out of source):

• use Mock Debug with PR support DAP's "restart" request vscode-mock-debug#79
• set capability supportsRestartRequest to true
• start debugging the sample "sampleWorkspace/readme.md"
• set breakpoint in line 28
• continue to breakpoint

Observe: variables are shown in Variables view

• press "Restart" button in debug view

Observe: debugging restarts but Variables view is not cleared