Fix Issue#963: Partially decorating service implementing multiple interfaces throws

src/Autofac/Core/ISharingLifetimeScope.cs

@@ -50,5 +50,20 @@ public interface ISharingLifetimeScope : ILifetimeScope
         /// <param name="creator">Creation function.</param>
         /// <returns>An instance.</returns>
         object GetOrCreateAndShare(Guid id, Func<object> creator);
+
+        /// <summary>
+        /// Try to retrieve an instance based on a GUID key.
+        /// </summary>
+        /// <param name="id">Key to look up.</param>
+        /// <returns>An instance.</returns>
+        object Get(Guid id);
+
+        /// <summary>
+        /// Try to create an instance with a GUID key.
+        /// </summary>
+        /// <param name="id">Key.</param>
+        /// <param name="creator">Creation function.</param>
+        /// <returns>An instance.</returns>
+        object Create(Guid id, Func<object> creator);
     }
 }

src/Autofac/Core/Lifetime/LifetimeScope.cs

@@ -316,6 +316,41 @@ public object GetOrCreateAndShare(Guid id, Func<object> creator)
             return result;
         }
 
+        /// <summary>
+        /// Try to create an instance with a GUID key.
+        /// </summary>
+        /// <param name="id">Key.</param>
+        /// <param name="creator">Creation function.</param>
+        /// <returns>An instance.</returns>
+        public object Create(Guid id, Func<object> creator)
+        {
+            if (creator == null) throw new ArgumentNullException(nameof(creator));
+
+            lock (_synchRoot)
+            {
+                if (_sharedInstances.TryGetValue(id, out var result)) return result;
+
+                result = creator();
+                if (_sharedInstances.ContainsKey(id))
+                    throw new DependencyResolutionException(string.Format(CultureInfo.CurrentCulture, LifetimeScopeResources.SelfConstructingDependencyDetected, result.GetType().FullName));
+
+                _sharedInstances.TryAdd(id, result);
+
+                return result;
+            }
+        }
+
+        /// <summary>
+        /// Try to retrieve an instance based on a GUID key.
+        /// </summary>
+        /// <param name="id">Key to look up.</param>
+        /// <returns>An instance.</returns>
+        public object Get(Guid id)
+        {
+            _sharedInstances.TryGetValue(id, out var result);
+            return result;
+        }
+
         /// <summary>
         /// Gets the disposer associated with this container. Instances can be associated
         /// with it manually if required.

src/Autofac/Core/Resolving/InstanceLookup.cs

@@ -40,6 +40,7 @@ internal class InstanceLookup : IComponentContext, IInstanceLookup
     {
         private readonly IResolveOperation _context;
         private readonly ISharingLifetimeScope _activationScope;
+        private readonly IComponentRegistration? _decoratorTargetComponent;
         private readonly Service _service;
         private object? _newInstance;
         private bool _executed;
@@ -52,6 +53,7 @@ internal class InstanceLookup : IComponentContext, IInstanceLookup
         {
             _context = context;
             _service = request.Service;
+            _decoratorTargetComponent = request.DecoratorTarget;
             ComponentRegistration = request.Registration;
             Parameters = request.Parameters;
 
@@ -81,19 +83,43 @@ public object Execute()
             _executed = true;
 
             object? decoratorTarget = null;
-            object instance = ComponentRegistration.Sharing == InstanceSharing.None
-                ? Activate(Parameters, out decoratorTarget)
-                : _activationScope.GetOrCreateAndShare(ComponentRegistration.Id, () => Activate(Parameters, out decoratorTarget));
+
+            var sharing = _decoratorTargetComponent != null
+                ? _decoratorTargetComponent.Sharing
+                : ComponentRegistration.Sharing;
+
+            var resolveParameters = Parameters as Parameter[] ?? Parameters.ToArray();
+
+            _newInstance = _activationScope.Get(ComponentRegistration.Id);
+
+            if (_newInstance == null)
+            {
+                _newInstance = sharing == InstanceSharing.Shared
+                    ? _activationScope.Create(ComponentRegistration.Id, () => CreateInstance(Parameters))
+                    : CreateInstance(Parameters);
+            }
+
+            decoratorTarget = _newInstance;
+
+            _newInstance = InstanceDecorator.TryDecorateRegistration(
+                _service,
+                ComponentRegistration,
+                _newInstance,
+                _activationScope,
+                resolveParameters);
+
+            if (_newInstance != decoratorTarget)
+                ComponentRegistration.RaiseActivating(this, resolveParameters, ref _newInstance);
 
             var handler = InstanceLookupEnding;
             handler?.Invoke(this, new InstanceLookupEndingEventArgs(this, NewInstanceActivated));
 
             StartStartableComponent(decoratorTarget);
 
-            return instance;
+            return _newInstance;
         }
 
-        private void StartStartableComponent(object? instance)
+        private void StartStartableComponent(object instance)
         {
             if (instance is IStartable startable
                 && ComponentRegistration.Services.Any(s => (s is TypedService typed) && typed.ServiceType == typeof(IStartable))
@@ -111,24 +137,17 @@ private void StartStartableComponent(object? instance)
         private bool NewInstanceActivated => _newInstance != null;
 
         [SuppressMessage("CA1031", "CA1031", Justification = "General exception gets rethrown in a PropagateActivationException.")]
-        private object Activate(IEnumerable<Parameter> parameters, out object decoratorTarget)
+        private object CreateInstance(IEnumerable<Parameter> parameters)
         {
             ComponentRegistration.RaisePreparing(this, ref parameters);
 
             var resolveParameters = parameters as Parameter[] ?? parameters.ToArray();
 
             try
             {
-                decoratorTarget = _newInstance = ComponentRegistration.Activator.ActivateInstance(this, resolveParameters);
+                _newInstance = ComponentRegistration.Activator.ActivateInstance(this, resolveParameters);
 
                 ComponentRegistration.RaiseActivating(this, resolveParameters, ref _newInstance);
-
-                _newInstance = InstanceDecorator.TryDecorateRegistration(
-                    _service,
-                    ComponentRegistration,
-                    _newInstance,
-                    _activationScope,
-                    resolveParameters);
             }
             catch (ObjectDisposedException)
             {
@@ -145,19 +164,16 @@ private object Activate(IEnumerable<Parameter> parameters, out object decoratorT
                 // important. The ProvidedInstanceActivator will NOT dispose of the provided
                 // instance once the instance has been activated - assuming that it will be
                 // done during the lifetime scope's Disposer executing.
-                if (decoratorTarget is IDisposable instanceAsDisposable)
+                if (_newInstance is IDisposable instanceAsDisposable)
                 {
                     _activationScope.Disposer.AddInstanceForDisposal(instanceAsDisposable);
                 }
-                else if (decoratorTarget is IAsyncDisposable asyncDisposableInstance)
+                else if (_newInstance is IAsyncDisposable asyncDisposableInstance)
                 {
                     _activationScope.Disposer.AddInstanceForAsyncDisposal(asyncDisposableInstance);
                 }
             }
 
-            if (_newInstance != decoratorTarget)
-                ComponentRegistration.RaiseActivating(this, resolveParameters, ref _newInstance);
-
             return _newInstance;
         }
 
@@ -185,8 +201,6 @@ public void Complete()
             var beginningHandler = CompletionBeginning;
             beginningHandler?.Invoke(this, new InstanceLookupCompletionBeginningEventArgs(this));
 
-            // _newInstance will definitely have been instantiated by the time
-            // this is called.
             ComponentRegistration.RaiseActivated(this, Parameters, _newInstance!);
 
             var endingHandler = CompletionEnding;

src/Autofac/Features/Decorators/InstanceDecorator.cs

@@ -69,7 +69,7 @@ internal static class InstanceDecorator
                 invokeParameters[invokeParameters.Length - 2] = serviceParameter;
                 invokeParameters[invokeParameters.Length - 1] = contextParameter;
 
-                var resolveRequest = new ResolveRequest(decoratorService, decoratorRegistration, invokeParameters);
+                var resolveRequest = new ResolveRequest(decoratorService, decoratorRegistration, invokeParameters, registration);
                 instance = context.ResolveComponent(resolveRequest);
 
                 if (index < decoratorCount - 1)

src/Autofac/ResolveRequest.cs

@@ -15,10 +15,23 @@ public class ResolveRequest
         /// <param name="registration">The component registration for the service.</param>
         /// <param name="parameters">The parameters used when resolving the service.</param>
         public ResolveRequest(Service service, IComponentRegistration registration, IEnumerable<Parameter> parameters)
+            : this(service, registration, parameters, null)
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ResolveRequest"/> class.
+        /// </summary>
+        /// <param name="service">The service being resolved.</param>
+        /// <param name="registration">The component registration for the service.</param>
+        /// <param name="parameters">The parameters used when resolving the service.</param>
+        /// <param name="decoratorTarget">The target component to be decorated.</param>
+        public ResolveRequest(Service service, IComponentRegistration registration, IEnumerable<Parameter> parameters, IComponentRegistration? decoratorTarget = null)
         {
             Service = service;
             Registration = registration;
             Parameters = parameters;
+            DecoratorTarget = decoratorTarget;
         }
 
         /// <summary>
@@ -35,5 +48,7 @@ public ResolveRequest(Service service, IComponentRegistration registration, IEnu
         /// Gets the parameters used when resolving the service.
         /// </summary>
         public IEnumerable<Parameter> Parameters { get; }
+
+        public IComponentRegistration? DecoratorTarget { get; }
     }
 }

test/Autofac.Test/Features/Decorators/DecoratorTests.cs

@@ -104,7 +104,7 @@ public void DecoratedInstancePerDependencyRegistrationCanIncludeOtherServices()
             Assert.NotSame(serviceInstance, decoratedServiceInstance);
         }
 
-        [Fact(Skip = "Issue #963")]
+        [Fact]
         public void DecoratedInstancePerLifetimeScopeRegistrationCanIncludeOtherServices()
         {
             var builder = new ContainerBuilder();
@@ -128,10 +128,10 @@ public void DecoratedInstancePerLifetimeScopeRegistrationCanIncludeOtherServices
             var decoratedServiceInstance = container.Resolve<IDecoratedService>();
             Assert.IsType<DecoratorA>(decoratedServiceInstance);
 
-            Assert.Same(serviceInstance, decoratedServiceInstance);
+            Assert.Same(serviceInstance, decoratedServiceInstance.Decorated);
         }
 
-        [Fact(Skip = "Issue #963")]
+        [Fact]
         public void DecoratedSingleInstanceRegistrationCanIncludeOtherServices()
         {
             var builder = new ContainerBuilder();
@@ -149,8 +149,13 @@ public void DecoratedSingleInstanceRegistrationCanIncludeOtherServices()
             Assert.NotNull(decoratedServiceRegistration);
             Assert.Same(serviceRegistration, decoratedServiceRegistration);
 
-            Assert.IsType<ImplementorA>(container.Resolve<IService>());
-            Assert.IsType<DecoratorA>(container.Resolve<IDecoratedService>());
+            var serviceInstance = container.Resolve<IService>();
+            Assert.IsType<ImplementorA>(serviceInstance);
+
+            var decoratedServiceInstance = container.Resolve<IDecoratedService>();
+            Assert.IsType<DecoratorA>(decoratedServiceInstance);
+
+            Assert.Same(serviceInstance, decoratedServiceInstance.Decorated);
         }
 
         [Fact]

test/Autofac.Test/Features/Decorators/OpenGenericDecoratorTests.cs

@@ -222,7 +222,7 @@ public void DecoratedInstancePerDependencyRegistrationCanIncludeOtherServices()
             Assert.NotSame(serviceInstance, decoratedServiceInstance);
         }
 
-        [Fact(Skip = "Issue #963")]
+        [Fact]
         public void DecoratedInstancePerLifetimeScopeRegistrationCanIncludeOtherServices()
         {
             var builder = new ContainerBuilder();
@@ -241,15 +241,15 @@ public void DecoratedInstancePerLifetimeScopeRegistrationCanIncludeOtherServices
             Assert.Same(serviceRegistration, decoratedServiceRegistration);
 
             var serviceInstance = container.Resolve<IService<int>>();
-            Assert.IsType<DecoratorA<int>>(serviceInstance);
+            Assert.IsType<ImplementorA<int>>(serviceInstance);
 
             var decoratedServiceInstance = container.Resolve<IDecoratedService<int>>();
             Assert.IsType<DecoratorA<int>>(decoratedServiceInstance);
 
-            Assert.Same(serviceInstance, decoratedServiceInstance);
+            Assert.Same(serviceInstance, decoratedServiceInstance.Decorated);
         }
 
-        [Fact(Skip = "Issue #963")]
+        [Fact]
         public void DecoratedSingleInstanceRegistrationCanIncludeOtherServices()
         {
             var builder = new ContainerBuilder();
@@ -268,12 +268,12 @@ public void DecoratedSingleInstanceRegistrationCanIncludeOtherServices()
             Assert.Same(serviceRegistration, decoratedServiceRegistration);
 
             var serviceInstance = container.Resolve<IService<int>>();
-            Assert.IsType<DecoratorA<int>>(serviceInstance);
+            Assert.IsType<ImplementorA<int>>(serviceInstance);
 
             var decoratedServiceInstance = container.Resolve<IDecoratedService<int>>();
             Assert.IsType<DecoratorA<int>>(decoratedServiceInstance);
 
-            Assert.Same(serviceInstance, decoratedServiceInstance);
+            Assert.Same(serviceInstance, decoratedServiceInstance.Decorated);
         }
 
         [Fact]