When attempting to register a startable component that depends on a service whose implementation “decorates” the same service interface, Castle fails to resolve the startable component, claiming that the dependency cannot be resolved. Curiously enough, explicitly resolving the startable component works as expected. I have seen this behavior in both Castle Windsor 2.5 and 2.5.1. Please see the below NUnit test case:
UPDATE
I’ve discovered that I can get the startable mechanism to work, but I need to separate the registrations of the IFoo implementers into a separate container.Register() call from the registration of the startable component. The IFoo registrations must happen first. Even more interestingly, this does not work if I use an IWindsorInstaller to install the components. Please see additional test cases below:
UPDATE
Installing the IFoo implementers in a separate installer, in a separate call to container.Install() works. Installing the startable component by including its IWindsorInstaller in the params[] list to a single call to container.Install() does not work, but installing it in a separate call to container.Install() does work. I have consolidated all test cases into the below code snippet:
using System;
using Castle.Facilities.Startable;
using Castle.MicroKernel.Registration;
using Castle.MicroKernel.SubSystems.Configuration;
using Castle.Windsor;
using NUnit.Framework;
namespace Tests
{
[TestFixture]
public class TestProblemsWithStartableAndDecorators
{
/// <summary>
/// This test passes with the following output to the console:
///
/// foo decorator
/// typeof decorated : Foo
/// startable constructor
/// typeof foo : FooDecorator
///
/// </summary>
[Test]
public void TestUsingResolve()
{
using (var container = new WindsorContainer())
{
container.AddFacility<StartableFacility>(f => f.DeferredStart());
container.Register(
Component.For<IFoo>().ImplementedBy<FooDecorator>(),
Component.For<IFoo>().ImplementedBy<Foo>(),
Component.For<IGetStarted>().ImplementedBy<GetStarted>()
);
container.Resolve<IGetStarted>();
}
}
/// <summary>
/// This test should pass with the same output as the above test.
/// However, it fails with the following exeption:
///
/// Castle.MicroKernel.Handlers.HandlerException : Can't create component 'Tests.TestProblemsWithStartableAndDecorators+FooDecorator' as it has dependencies to be satisfied.
/// Tests.TestProblemsWithStartableAndDecorators+FooDecorator is waiting for the following dependencies:
///
/// Services:
/// - Tests.TestProblemsWithStartableAndDecorators+IFoo.
/// A dependency cannot be satisfied by itself, did you forget to add a parameter name to differentiate between the two dependencies?
///
/// Tests.TestProblemsWithStartableAndDecorators+foo is registered and is matching the required service, but cannot be resolved.
/// </summary>
[Test]
public void TestUsingStartable()
{
using (var container = new WindsorContainer())
{
container.AddFacility<StartableFacility>(f => f.DeferredStart());
container.Register(
Component.For<IFoo>().ImplementedBy<FooDecorator>(),
Component.For<IFoo>().ImplementedBy<Foo>(),
Component.For<IGetStarted>().ImplementedBy<GetStarted>().Start()
);
}
}
public interface IFoo
{
}
public class Foo : IFoo
{
}
public class FooDecorator : IFoo
{
public FooDecorator(IFoo decorated)
{
Console.WriteLine("foo decorator");
Console.WriteLine(" typeof decorated : " + decorated.GetType().Name);
}
}
public interface IGetStarted
{
}
public class GetStarted : IGetStarted
{
public GetStarted(IFoo foo)
{
Console.WriteLine("startable constructor");
Console.WriteLine(" typeof foo : " + foo.GetType().Name);
}
}
// works
[Test]
public void TestUsingStartableWithSeparateRegistrations()
{
using (var container = new WindsorContainer())
{
container.AddFacility<StartableFacility>(f => f.DeferredStart());
container.Register(Component.For<IFoo>().ImplementedBy<FooDecorator>(),
Component.For<IFoo>().ImplementedBy<Foo>());
container.Register(Component.For<IGetStarted>().ImplementedBy<GetStarted>().Start());
}
}
// fails
[Test]
public void TestUsingStartableWithSeparateRegistrationsRegisteringStartableFirst()
{
using (var container = new WindsorContainer())
{
container.AddFacility<StartableFacility>(f => f.DeferredStart());
container.Register(Component.For<IGetStarted>().ImplementedBy<GetStarted>().Start());
container.Register(Component.For<IFoo>().ImplementedBy<FooDecorator>(),
Component.For<IFoo>().ImplementedBy<Foo>());
}
}
// fails
[Test]
public void TestUsingStartableWithInstaller()
{
using (var container = new WindsorContainer())
{
container.AddFacility<StartableFacility>(f => f.DeferredStart());
container.Install(new TestInstaller());
}
}
public class TestInstaller : IWindsorInstaller
{
public void Install(IWindsorContainer container,
IConfigurationStore store)
{
container.Register(Component.For<IFoo>().ImplementedBy<FooDecorator>(),
Component.For<IFoo>().ImplementedBy<Foo>());
container.Register(Component.For<IGetStarted>().ImplementedBy<GetStarted>().Start());
}
}
// works
[Test]
public void TestUsingStartableWithSeparateFooInstaller()
{
using (var container = new WindsorContainer())
{
container.AddFacility<StartableFacility>(f => f.DeferredStart());
container.Install(new FooInstaller());
container.Register(Component.For<IGetStarted>().ImplementedBy<GetStarted>().Start());
}
}
// fails
[Test]
public void TestUsingStartableWithSeparateInstallers()
{
using (var container = new WindsorContainer())
{
container.AddFacility<StartableFacility>(f => f.DeferredStart());
container.Install(new FooInstaller(), new StartableInstaller());
}
}
// works
[Test]
public void TestUsingStartableWithSeparateCallsToInstall()
{
using (var container = new WindsorContainer())
{
container.AddFacility<StartableFacility>(f => f.DeferredStart());
container.Install(new FooInstaller());
container.Install(new StartableInstaller());
}
}
public class FooInstaller : IWindsorInstaller
{
public void Install(IWindsorContainer container,
IConfigurationStore store)
{
container.Register(Component.For<IFoo>().ImplementedBy<FooDecorator>(),
Component.For<IFoo>().ImplementedBy<Foo>());
}
}
public class StartableInstaller : IWindsorInstaller
{
public void Install(IWindsorContainer container,
IConfigurationStore store)
{
container.Register(Component.For<IGetStarted>().ImplementedBy<GetStarted>().Start());
}
}
}
}
Fixed in HEAD. Will be part of 2.5.2 release. For future reference, here’s the bug report.