DebugSession setBreakPointsRequest Regression

[GordonSmith]

• VSCode Version: 1.44.2
• OS Version: Windows 10 (2004)

Steps to Reproduce:

1. Implement a DebugSession with a setBreakPointsRequest method
2. Add some breakpoints to your code before submitting
3. In DebugSession.setBreakPointsRequest return the "response" without adding a "breakpoints" array.

Does this issue occur when all extensions are disabled?: NA

My debug sessions are hanging (not proceeding to the "ConfigurationDoneRequest") with the following code:

    protected setBreakPointsRequest(response: DebugProtocol.SetBreakpointsResponse, args: DebugProtocol.SetBreakpointsArguments): void {
        this.sendResponse(response);
    }

But proceed as expected with the following:

    protected setBreakPointsRequest(response: DebugProtocol.SetBreakpointsResponse, args: DebugProtocol.SetBreakpointsArguments): void {
        response.body = {
            breakpoints: []
        };
        this.sendResponse(response);
    }

The above code is quite old, so suspect this is a regression in VS Code

[isidorn]

Please change https://github.com/microsoft/vscode-mock-debug such that this issue is reproducable. So I can clone and see the issue.

[GordonSmith]

@isidorn - microsoft/vscode-mock-debug#42

[GordonSmith]

Previous behaviour:

• The program would have completed without any breaks and "configurationDoneRequest" would have been called..

New behaviour:

• The program appears to be "stuck" and "configurationDoneRequest" is never called.

[weinand]

@GordonSmith the spec says that the body and the breakpoints array are mandatory, so if you are sending a response without a breakpoints array you are violating the spec (and your extension might fail in other clients).

@isidorn Since VS Code was handling this situation gracefully before, we should continue to do so. Since this new behavior was already in 1.44 it is not a regression in Insiders. So there is no pressure to fix this for Insiders. But most likely the fix is so small and low-risk that we could easily ship it in 1.45.

[GordonSmith]

@weinand thanks for the update. 100% agree about the specification.

But this issue is with the vscode-debugadapter -> DebugSession , either its dispatchEvent logic or an invalid declaration?

The setBreakpointsRequest declaration is:

protected setBreakPointsRequest(response: DebugProtocol.SetBreakpointsResponse, args: DebugProtocol.SetBreakpointsArguments, request?: DebugProtocol.Request): void;

Where SetBreakpointsResponse is declared as:

interface SetBreakpointsResponse extends Response {
    body: {
        breakpoints: Breakpoint[];
    };
}

Isn't the onus on the caller of setBreakPointsRequest to honour the declaration?

I would suggest that its this cast that prevented TypeScript from catching this specific issue at compile time...: https://github.com/microsoft/vscode-debugadapter-node/blob/master/adapter/src/debugSession.ts#L506