Umbraco-CMS: LightInject Registering by convention is not possible as you have replaced the default AssemblyScanner.

I can’t register dependencies by convention.

container.RegisterAssembly() is completely unusable as the AssemblyScanner has been replaced with a NOP stub.

See https://github.com/umbraco/Umbraco-CMS/blob/v8/contrib/src/Umbraco.Core/Composing/LightInject/LightInjectContainer.cs

Line 61 Line 254

Umbraco version

I am seeing this issue on Umbraco version: 8.5.2

Reproduction

Specifics

Steps to reproduce

Spin up umbraco 8.5.2 site

Add the following to a c# file

    public class Composer : IUserComposer
    {
        public void Compose(Composition composition)
        {
            var container = composition.Concrete as ServiceContainer;
            Debug.Assert(container != null, nameof(container) + " != null");
            container.RegisterAssembly(typeof(IFoo).Assembly);

            // The following throws
            container.GetInstance<IFoo>();
        }
    }

    public interface IFoo
    {
        string Ping();
    }

    public class Foo : IFoo
    {
        public string Ping()
        {
            return "Pong";
        }
    }

Expected result

I expect to be able to resolve an instance implementing IFoo

Actual result

It doesn’t work.

However if I blast over the NOP scanner with the following it works as one would expect.

        public void Compose(Composition composition)
        {
            var container = composition.Concrete as ServiceContainer;
            Debug.Assert(container != null, nameof(container) + " != null");

            // Replace NOP scanner
            container.AssemblyScanner = new ServiceContainer().AssemblyScanner;

            container.RegisterAssembly(typeof(IFoo).Assembly);
            // The following does not throw
            container.GetInstance<IFoo>();
        }