InSingletonScope bug (?) when requesting an instance in OnActivation callback

[Anlo2846]

A slightly contrived example exhibiting a strange behaviour of InSingletonScope() in Ninject v3.2.2. Our actual code involves several more classes but we get the same problem, a singleton scope class in created twice.

        [Test]
        public void NinjectShouldCreateOnlyOneHandlerInstance()
        {
            IKernel kernel = new StandardKernel();
            kernel.Bind<Handler>().ToSelf().InSingletonScope();
            kernel.Bind<Module>().ToSelf().InSingletonScope().OnActivation(_ => kernel.Get<Handler>());
            kernel.Get<Handler>();
        }

        public class Handler
        {
            public Handler(Module module)
            {
                Debug.WriteLine("Handler ctor");
            }
        }

        public class Module
        {
            public Module()
            {
                Debug.WriteLine("Module ctor");
            }
        }

Debug output:

Module ctor
Handler ctor
Handler ctor

I think the problem is that a Handler is requested while it is being created. But I would expect the original request (called from the test method) to return the instance created by the OnActivation callback. Or if it isn't possible, to throw an exception rather than creating the singleton scope class twice.

[scott-xu]

Fixed by 8de2b02