Support for debugging tasks

[davidanthoff]

As far as I can tell there is currently no support to debug tasks that are started by code that is running in JuliaInterpreter, correct?

I think (but am not sure) that from the VS Code extension point of view the following would be a good design: we add another argument to debug_command called create_task_callback. Whenever JuliaInterpreter is about to run the (low level) statement that would create a new task it would then just call that callback instead and that callback is then in charge of actually creating the new task.

The call that JuliaInterpreter.jl would need to detect here is probably Core.Task.

The signature for the callback would be (f, reserved_stack::Int=0).

In the VS Code debugger, our implementation for that callback function would look like this in pseudo-code:

function task_create_callback(f, reserved_stack)
    new_f = () -> begin
        frame = construct_juliainterpreter_frame(...)
        setup_comm_with_debugger_msg_processing_task()
        while # our main normal debugger loop
            # get next command from debugger msg processing task
            debug_command(....)
        end
    end

    return Core.Task(new_f, reserved_stack)
end

For the UI we could then just treat each task as a thread, and thus expose tasks as primary objects in the debugger UI.

[MJLHThomassen-Sorama]

Any updatse on this?

[jjd35]

Is this still going to be added at some point?

[timholy]

Anyone can submit a PR. It's not on my agenda, but perhaps it's on yours?

[davidanthoff]

@timholy could I just add another branch to this if statement

JuliaInterpreter.jl/src/interpret.jl

Line 260 in 443d672

if fargs[1] === Core.invoke # invoke needs special handling

that handles the case fargs[1] == Core.Task for this?