Calling emit() on an object, only seems to deliver the signal to that object not others connected to the same signal

[pcbeard]

See attached project. Try running swift TestSignals and notice that if SpinningCube._input() is active, and ListenerNode._input() is commented out, that ListenerNode._on_pressed() never gets called. It also seems to be that if you try to use SpinningCube.pressed from ListenerNode._ready(), without also using the #signal() macro in the ListenerNode class, this will fail to find the signal with this error message:

ERROR: In Object of type 'ListenerNode': Attempt to connect nonexistent signal 'pressed' to callable 'ListenerNode::_on_pressed'.
at: connect (core/object/object.cpp:1282)

HelloSwiftGodotKit.zip

[PadraigK]

This is behaving as expected, but its understandable why anyone would see it as a bug :/

Godot's signal mechanism connects an instance emitting the signal to another node. This is unusual for a notification pattern which normally allows another object to globally observe a notification/signal without needing to know about the emitting instance.

From the code in the zip file:

var pressedSignal = SpinningCube.pressed
@Godot
class ListenerNode: Node {
    #signal("pressed", arguments: ["event" : InputEvent.self])
    
    @Callable func _on_pressed(event: InputEvent) {
        print("event = \(event)")
    }
    
    override func _ready() {
        connect(signal: pressedSignal, to: self, method: "_on_pressed")    
    }
    
    override func _input(event: InputEvent) {
        guard event.isPressed() && !event.isEcho() else { return }
        emit(signal: pressedSignal, event)
    }
}

In _ready here, the code is attempting to connect an instance of ListenerNode to a signal which ListenerNode does not emit.

Compared with:

    func addSpinningCube(_ pos: Vector3) {
        let n = SpinningCube()
        n.position = pos
        rootNode.addChild(node: n)
        if !listening {
            n.connect(signal: pressedSignal, to: n, method: "_on_pressed")
            listening = true
        }
    }

This call to connect is correct because it's connecting an instance of SpinningCube.

[pcbeard]

Yes, I see the error of my ways now. Thanks!