Decorated Instances do not get properties injected if they are marked with AllowCircularDependencies

[alistairjevans]

Related to #1200, but this is definitely just a v6 issue that wasn't in v5.

If you have a decorated instance, with property injection, and circular dependencies allowed on said property injection, the properties won't be injected.

The instance used for property injection in that event is the decorator, rather than the instance.

This (new) test fails:

private interface IMyService
{
    void AssertProp();
}

private sealed class DecoratedService : IMyService
{
    public string Prop { get; set; }

    public void AssertProp()
    {
        if (Prop is null)
        {
            throw new NullReferenceException();
        }
    }
}

private sealed class ServiceDecorator : IMyService
{
    private readonly IMyService _decorating;

    public ServiceDecorator(IMyService decorating)
    {
        _decorating = decorating;
    }

    public void AssertProp()
    {
        _decorating.AssertProp();
    }
}

[Fact]
public void DecoratedInstanceWithPropertyInjectionAllowingCircularReferencesStillInjects()
{
    var val = "Value";

    var builder = new ContainerBuilder();
    builder.RegisterInstance(val);
    builder.RegisterType<DecoratedService>().As<IMyService>().PropertiesAutowired(PropertyWiringOptions.AllowCircularDependencies);
    builder.RegisterDecorator<ServiceDecorator, IMyService>();

    var container = builder.Build();
    var instance = container.Resolve<IMyService>();

    instance.AssertProp();
}

Luckily, unlike #1200, this one should be an easy fix. I just need to ensure I capture the new instance and pass that into the event handler.

[tillig]

this is definitely just a v6 issue that wasn't in v6

I think you mean "a v6 issue that wasn't in v5." 😆 But, yeah, good find. I'm glad we're catching this stuff.

[alistairjevans]

Fixing this one may actually be the thing that unblocks the dynamic proxy issue as well (autofac/Autofac.Extras.DynamicProxy#40)