794078 - Actors should return a response promise instead of sending reply packets directly

Status: RESOLVED INVALID

(DevTools :: Debugger, defect, P3)

Description

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

An actor shouldn't have to know about |send| to do async, it should only have to deal in packets. If it is going to respond in an async fashion, it should return a promise. If it doesn't return anything, that should be an error.

Comment 1

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

There are currently three request methods in script.js that send responses via |this.conn.send| directly rather than returning a packet/promise(packet):

1. onAttach

2. onInterrupt

3. onExceptionUnwind

The reason they do this is because after they send the response, they push a new event loop.

If we tried to enter the event loop and then return the packet, we would just hang forever, so that's a no go.

Perhaps we can executeSoon-ify the entering of an event loop so it happens on the next tick after returning the packet? I don't think that would give us the guarantee that we won't receive a new packet before entering that nested event loop, though.

I think whatever fix we come up with might have to be integrated with bug 908452

Comment 2

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

Woops, onExceptionUnwind is definitely not a request method. Make that 2 request methods that use |this.conn.send| directly.

Comment 3

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

More request methods responding with |send| directly:

* gcli.js: GcliActor.prototype.execute - looks easy to port over at first glance

* tracer.js: TraceActor.prototype.onDetach - looks easy to port over at first glance

Comment 4

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

I think that is all of them.

Comment 5

[Jason Laster [:jlast]]

this is no longer relevant with the protocol work