Why is Swinject model class registered without ".inObjectScope( .Container )" producing a singleton?

Question

This question is for people with a lot of experience of Swinject for Swift.

I will show the problematic code, and my question is at the bottom.

There's quite a lot of code, sorry about that.

This is MySwinjectStoryboard.swift registration:

import Swinject

extension SwinjectStoryboard
{
    class func setup ()
    {
        defaultContainer.register( Stopwatch.self )
        {
            responder in Stopwatch( 
                signals: responder.resolve( SignalsService.self )! 
            )
        }

        defaultContainer.register( SignalsService.self ) 
        { 
            _ in SignalsService() 
        }.inObjectScope( .Container )

        defaultContainer.register( ImageService.self )
        {
            responder in ImageService(
                signals: responder.resolve( SignalsService.self )!
                , stopwatch: responder.resolve( Stopwatch.self )!
            )
        }.inObjectScope( .Container )

        defaultContainer.registerForStoryboard( StartUpViewController.self )
        {
            resolvable, viewController in
            viewController.stopwatch = resolvable.resolve( Stopwatch.self )!
            viewController.image = resolvable.resolve( ImageService.self )!
        }
    }
}

This is Stopwatch.swift, which simply pauses a while before firing an onComplete handler:

import Foundation

class Stopwatch: StopwatchProtocol
{
    var key: String { return "Stopwatch_\( _key ).Complete" }

    private var
    _signals: SignalsProtocol
    , _key: UInt16
    , _timer: NSTimer?
    , _data: AnyObject?

    func startWith ( 
        Delay delay: Double
        , ForListener closure: ( String, Any? ) -> Void 
    ){
        _data = nil
        _startWith( Delay: delay, ForListener: closure )
    }

    func stop ()
    {
        guard let timer = _timer else { return }
        timer.invalidate()
        _timer = nil
        _data = nil
    }

    private func _startWith ( 
        Delay delay: Double
        , ForListener closure: ( String, Any? ) -> Void 
    ){
        stop()

        _timer = NSTimer.scheduledTimerWithTimeInterval(
            NSTimeInterval( delay )
            , target: self
            , selector: #selector( _onTimerComplete )
            , userInfo: nil
            , repeats: false
        )
    }

    @objc private func _onTimerComplete ()
    {
        stop()
        print( "stopwatch with key `\( key )` complete." )
    }

    required init ( signals: SignalsProtocol )
    {
        _signals = signals
        _key = getPrimaryKey()
        print( "primary key: \( _key )" )
    }
}

ImageService.swift presently simply accepts a signals and a stopwatch property via an init function:

protocol ImageProtocol {}

class ImageService: ImageProtocol
{
    private let
  _signals: SignalsProtocol
    , _stopwatch: StopwatchProtocol

    required init ( 
    signals: SignalsProtocol
    , stopwatch: StopwatchProtocol 
  ){
        _signals = signals
        _stopwatch = stopwatch

        lo( "ImageService key: \( _stopwatch.key )" )
    }
}

SignalsService.swift is currently an empty Model class:

protocol SignalsProtocol {}

class SignalsService: SignalsProtocol {}

Whilst StartUpViewController.swift is a basic UIViewController that currently just accepts its injected properties:

import UIKit

class StartUpViewController: UIViewController
{
    var image: ImageService? { 
        willSet { 
            guard _image == nil else { return }
            _image = newValue
        }
    }

    var signals: SignalsService? { 
        willSet { 
            guard _signals == nil else { return }
            _signals = newValue 
        }
    }

    var stopwatch: StopwatchProtocol? { 
        willSet { 
            guard _stopwatch == nil else { return }
            _stopwatch = newValue
            print( "StartUpViewController key: \( _stopwatch.key )" ) 
        } 
    }

    internal var
    _image: ImageService!
    , _signals: SignalsService!
    , _stopwatch: Stopwatch!    
}

And finally getPrivateKey() is simply a global static, returning unique Ints:

private var _primaryKey = UInt16( 0 )

func getPrimaryKey () -> UInt16
{
    _primaryKey += 1
    return _primaryKey
}

Now as I understand it, the way I have registered Stopwatch.swift in MySwinjectStoryboard.swift means that each time an instance is injected, it will be a new, discrete instance. However, both ImageService.swift and StartUpViewController.swift are being injected with the same instance:

StartUpViewController key: Stopwatch_2.Complete
ImageService key: Stopwatch_2.Complete

ImageService's key ought to be:

ImageService key: Stopwatch_3.Complete

Does anyone know why this is happening, please? Thank you.

Answer 1

Default scope for services is .Graph. From documentation:

With ObjectScope.Graph, an instance is always created, as in ObjectScope.None, if you directly call resolve method of a container, but instances resolved in factory closures are shared during the resolution of the root instance to construct the object graph.

If you want a unique instance to be created for each reference even during object graph resolution, you should use object scope .None, i.e.

defaultContainer.register(Stopwatch.self) { resolver in 
    Stopwatch(signals: resolver.resolve(SignalsService.self)!)
}.inObjectScope(.None)