`AutoActivate()` hides a registration's default "self" service

[nblumhardt]

Describe the Bug

A registration like builder.Register<A>() defaults to exposing the typed service A on the component.

Adding AutoActivate() to the registration hides this default. Since the name AutoActivate() doesn't suggest that it has anything to do with exposed services, this seems like a bug or rough edge in the API.

Steps to Reproduce

public class StartableTests
{
    [Fact]
    public void AutoActivate_DoesNotHideDefaultSelfService()
    {
        var builder = new ContainerBuilder();
        builder.RegisterType<MyComponent2>().AutoActivate();
        using var container = builder.Build();
        Assert.True(container.IsRegistered<MyComponent2>());
    }

The test can be made to succeed by adding AsSelf() to the registration.

Expected Behavior

AutoActivate() would not alter the services exposed by the component in a user-visible manner.

Dependency Versions

develop branch.

Additional Info

Happy to try to fix this and send a PR, just opening this first to gauge whether it's a known issue or by design. Not in any way blocked on this :-)

[tillig]

I don't think it's by design, I'm guessing we just don't have a test for the issue mentioned. It'd be awesome to get a PR for it if you're able. Thanks!

[vjred]

Could you please check if #1456 is a breaking change to IComponentContext.ResolveComponent introduced by the change in this PR? Any thoughts on how to fix it?