Custom handlers not override built in handlers correctly

Directory.Build.targets

@@ -17,6 +17,9 @@
     <PackageReference Update="Microsoft.Extensions.Logging" Version="2.0.0" />
     <PackageReference Update="Microsoft.Extensions.Logging.Debug" Version="2.0.0" />
     <PackageReference Update="Microsoft.Extensions.Configuration" Version="2.0.0" />
+    <PackageReference Update="Microsoft.Extensions.Configuration.Binder" Version="2.0.0" />
+    <PackageReference Update="Microsoft.Extensions.Options" Version="2.0.0" />
+    <PackageReference Update="Microsoft.Extensions.Options.ConfigurationExtensions" Version="2.0.0" />
     <PackageReference Update="Microsoft.Extensions.DependencyInjection" Version="2.0.0" />
     <PackageReference Update="Newtonsoft.Json" Version="11.0.2" />
     <PackageReference Update="Microsoft.NET.Test.Sdk" Version="16.7.1" />
@@ -45,4 +48,4 @@
     <PackageReference Update="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="3.4.0" />
     <PackageReference Update="DryIoc.Internal" Version="4.5.0" />
   </ItemGroup>
-</Project>
+</Project>

src/Client/LanguageClientOptions.cs

@@ -18,6 +18,7 @@ public LanguageClientOptions()
         {
             WithAssemblies(typeof(LanguageClientOptions).Assembly, typeof(LspRequestRouter).Assembly);
         }
+
         public ClientCapabilities ClientCapabilities { get; set; } = new ClientCapabilities {
             Experimental = new Dictionary<string, JToken>(),
             Window = new WindowClientCapabilities(),
@@ -52,7 +53,8 @@ ILanguageClientRegistry IJsonRpcHandlerRegistry<ILanguageClientRegistry>.AddHand
         ILanguageClientRegistry IJsonRpcHandlerRegistry<ILanguageClientRegistry>.AddHandler(JsonRpcHandlerFactory handlerFunc, JsonRpcHandlerOptions? options) =>
             AddHandler(handlerFunc, options);
 
-        ILanguageClientRegistry IJsonRpcHandlerRegistry<ILanguageClientRegistry>.AddHandler(IJsonRpcHandler handler, JsonRpcHandlerOptions? options) => AddHandler(handler, options);
+        ILanguageClientRegistry IJsonRpcHandlerRegistry<ILanguageClientRegistry>.AddHandler(IJsonRpcHandler handler, JsonRpcHandlerOptions? options) =>
+            AddHandler(handler, options);
 
         ILanguageClientRegistry IJsonRpcHandlerRegistry<ILanguageClientRegistry>.AddHandler<TTHandler>(JsonRpcHandlerOptions? options) => AddHandler<TTHandler>(options);
 

src/Client/LanguageClientServiceCollectionExtensions.cs

@@ -3,6 +3,7 @@
 using System.Linq;
 using System.Reflection;
 using DryIoc;
+using MediatR;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
@@ -28,7 +29,7 @@ internal static IContainer AddLanguageClientInternals(this IContainer container,
                 nonPublicServiceTypes: true,
                 ifAlreadyRegistered: IfAlreadyRegistered.Keep
             );
-            if (!EqualityComparer<OnUnhandledExceptionHandler?>.Default.Equals(  options.OnUnhandledException, default))
+            if (!EqualityComparer<OnUnhandledExceptionHandler?>.Default.Equals(options.OnUnhandledException, default))
             {
                 container.RegisterInstance(options.OnUnhandledException);
             }
@@ -79,7 +80,7 @@ internal static IContainer AddLanguageClientInternals(this IContainer container,
 
                     if (providedConfiguration != null)
                     {
-                        builder.CustomAddConfiguration((providedConfiguration.ImplementationInstance as IConfiguration)!);
+                        builder.CustomAddConfiguration(( providedConfiguration.ImplementationInstance as IConfiguration )!);
                     }
 
                     //var didChangeConfigurationProvider = _.GetRequiredService<DidChangeConfigurationProvider>();

src/JsonRpc.Generators/GenerateHandlerMethodsGenerator.cs

@@ -171,8 +171,9 @@ MemberDeclarationSyntax MakeAction(TypeSyntax syntax)
                 yield return MakeAction(CreateAsyncAction(true, requestType));
                 if (capability != null)
                 {
-                    yield return MakeAction(CreateAction(requestType, capability));
-                    yield return MakeAction(CreateAsyncAction(requestType, capability));
+                    method = method.WithExpressionBody(
+                        GetNotificationCapabilityHandlerExpression(GetMethodName(handlerInterface), requestType, capability)
+                    );
                     yield return MakeAction(CreateAction(requestType, capability));
                     yield return MakeAction(CreateAsyncAction(requestType, capability));
                 }

src/JsonRpc/JsonRpcServerServiceCollectionExtensions.cs

@@ -1,6 +1,8 @@
 using System;
 using System.IO.Pipelines;
 using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
 using DryIoc;
 using MediatR;
 using Microsoft.Extensions.DependencyInjection;
@@ -79,23 +81,51 @@ internal static IContainer AddJsonRpcMediatR(this IContainer container)
             container.RegisterMany(new[] { typeof(IMediator).GetAssembly() }, Registrator.Interfaces, Reuse.ScopedOrSingleton);
             container.RegisterMany<RequestContext>(Reuse.Scoped);
             container.RegisterDelegate<ServiceFactory>(context => context.Resolve, Reuse.ScopedOrSingleton);
+            container.Register(typeof(IRequestHandler<,>), typeof(RequestHandler<,>));
+            container.Register(typeof(IRequestHandler<,>), typeof(RequestHandlerDecorator<,>), setup: Setup.Decorator);
+
+            return container;
+        }
+
+        class RequestHandler<T, R> : IRequestHandler<T, R> where T : IRequest<R>
+        {
+            private readonly IRequestContext _requestContext;
+
+            public RequestHandler(IRequestContext requestContext)
+            {
+                _requestContext = requestContext;
+            }
+            public Task<R> Handle(T request, CancellationToken cancellationToken)
+            {
+                return ((IRequestHandler<T, R>) _requestContext.Descriptor.Handler).Handle(request, cancellationToken);
+            }
+        }
+
+        class RequestHandlerDecorator<T, R> : IRequestHandler<T, R> where T : IRequest<R>
+        {
+            private readonly IRequestHandler<T, R>? _handler;
+            private readonly IRequestContext? _requestContext;
+
+            public RequestHandlerDecorator(IRequestHandler<T, R>? handler = null, IRequestContext? requestContext = null)
+            {
+                _handler = handler;
+                _requestContext = requestContext;
+            }
+            public Task<R> Handle(T request, CancellationToken cancellationToken)
+            {
+                if (_requestContext == null)
+                {
+                    if (_handler == null)
+                    {
+                        throw new NotImplementedException($"No request handler was registered for type {typeof(IRequestHandler<T, R>).FullName}");
 
-            return container.With(
-                rules => rules.WithUnknownServiceResolvers(
-                    request => {
-                        if (request.ServiceType.IsGenericType && typeof(IRequestHandler<,>).IsAssignableFrom(request.ServiceType.GetGenericTypeDefinition()))
-                        {
-                            var context = request.Container.Resolve<IRequestContext?>();
-                            if (context != null)
-                            {
-                                return new RegisteredInstanceFactory(context.Descriptor.Handler);
-                            }
-                        }
-
-                        return null;
                     }
-                )
-            );
+
+                    return _handler.Handle(request, cancellationToken);
+                }
+
+                return ((IRequestHandler<T, R>) _requestContext.Descriptor.Handler).Handle(request, cancellationToken);
+            }
         }
 
         internal static IContainer AddJsonRpcServerInternals(this IContainer container, JsonRpcServerOptions options)

src/Protocol/ConfigureByConfigurationPathExtension.cs

@@ -0,0 +1,176 @@
+#if false
+using System;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Configuration.Binder;
+using Microsoft.Extensions.Primitives;
+
+// ReSharper disable once CheckNamespace
+namespace Microsoft.Extensions.Configuration
+{
+    public static class ConfigureByConfigurationPathExtension
+    {
+        /// <summary>
+        /// Registers a injected configuration service which TOptions will bind against.
+        /// </summary>
+        /// <typeparam name="TOptions">The type of options being configured.</typeparam>
+        /// <param name="services">The <see cref="IServiceCollection"/> to add the services to.</param>
+        /// <returns>The <see cref="IServiceCollection"/> so that additional calls can be chained.</returns>
+        public static IServiceCollection Configure<TOptions>(this IServiceCollection services)
+            where TOptions : class
+        {
+            if (services == null)
+            {
+                throw new ArgumentNullException(nameof(services));
+            }
+
+            return Configure<TOptions>(services, null);
+        }
+
+        /// <summary>
+        /// Registers a injected configuration service which TOptions will bind against.
+        /// </summary>
+        /// <typeparam name="TOptions">The type of options being configured.</typeparam>
+        /// <param name="services">The <see cref="IServiceCollection"/> to add the services to.</param>
+        /// <param name="sectionName">The name of the options instance.</param>
+        /// <returns>The <see cref="IServiceCollection"/> so that additional calls can be chained.</returns>
+        public static IServiceCollection Configure<TOptions>(this IServiceCollection services, string? sectionName)
+            where TOptions : class
+        {
+            if (services == null)
+            {
+                throw new ArgumentNullException(nameof(services));
+            }
+
+            services.AddOptions();
+            services.AddSingleton<IOptionsChangeTokenSource<TOptions>>(
+                _ => new ConfigurationChangeTokenSource<TOptions>(
+                    Options.Options.DefaultName,
+                    sectionName == null ? _.GetRequiredService<IConfiguration>() : _.GetRequiredService<IConfiguration>().GetSection(sectionName)
+                )
+            );
+            return services.AddSingleton<IConfigureOptions<TOptions>>(
+                _ => new NamedConfigureFromConfigurationOptions<TOptions>(
+                    Options.Options.DefaultName,
+                    sectionName == null ? _.GetRequiredService<IConfiguration>() : _.GetRequiredService<IConfiguration>().GetSection(sectionName)
+                )
+            );
+        }
+
+        /// <summary>
+        /// Registers a injected configuration service which TOptions will bind against.
+        /// </summary>
+        /// <typeparam name="TOptions">The type of options being configured.</typeparam>
+        /// <param name="services">The <see cref="IServiceCollection"/> to add the services to.</param>
+        /// <param name="configureBinder">Used to configure the <see cref="BinderOptions"/>.</param>
+        /// <returns>The <see cref="IServiceCollection"/> so that additional calls can be chained.</returns>
+        public static IServiceCollection Configure<TOptions>(this IServiceCollection services, Action<BinderOptions> configureBinder)
+            where TOptions : class
+        {
+            if (services == null)
+            {
+                throw new ArgumentNullException(nameof(services));
+            }
+
+            return Configure<TOptions>(services, Options.Options.DefaultName, configureBinder);
+        }
+
+        /// <summary>
+        /// Registers a injected configuration service which TOptions will bind against.
+        /// </summary>
+        /// <typeparam name="TOptions">The type of options being configured.</typeparam>
+        /// <param name="services">The <see cref="IServiceCollection"/> to add the services to.</param>
+        /// <param name="sectionName">The name of the options instance.</param>
+        /// <param name="configureBinder">Used to configure the <see cref="BinderOptions"/>.</param>
+        /// <returns>The <see cref="IServiceCollection"/> so that additional calls can be chained.</returns>
+        public static IServiceCollection Configure<TOptions>(this IServiceCollection services, string sectionName, Action<BinderOptions> configureBinder)
+            where TOptions : class
+        {
+            if (services == null)
+            {
+                throw new ArgumentNullException(nameof(services));
+            }
+
+            services.AddOptions();
+            services.AddSingleton<IOptionsChangeTokenSource<TOptions>>(_ => new ConfigurationChangeTokenSource<TOptions>(Options.Options.DefaultName, _.GetRequiredService<IConfiguration>().GetSection(sectionName)));
+            return services.AddSingleton<IConfigureOptions<TOptions>>(_ => new NamedConfigureFromConfigurationOptions<TOptions>(Options.Options.DefaultName, _.GetRequiredService<IConfiguration>().GetSection(sectionName), configureBinder));
+        }
+
+        /// <summary>
+        /// Registers a injected configuration service which TOptions will bind against.
+        /// </summary>
+        /// <typeparam name="TOptions">The type of options being configured.</typeparam>
+        /// <param name="builder">The <see cref="OptionsBuilder&lt;TOptions&gt;"/> to configure.</param>
+        /// <returns>The <see cref="IServiceCollection"/> so that additional calls can be chained.</returns>
+        public static OptionsBuilder<TOptions> Configure<TOptions>(this OptionsBuilder<TOptions> builder)
+            where TOptions : class
+        {
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            return Configure(builder, Options.Options.DefaultName);
+        }
+
+        /// <summary>
+        /// Registers a injected configuration service which TOptions will bind against.
+        /// </summary>
+        /// <typeparam name="TOptions">The type of options being configured.</typeparam>
+        /// <param name="builder">The <see cref="OptionsBuilder&lt;TOptions&gt;"/> to configure.</param>
+        /// <param name="sectionName">The name of the options instance.</param>
+        /// <returns>The <see cref="IServiceCollection"/> so that additional calls can be chained.</returns>
+        public static OptionsBuilder<TOptions> Configure<TOptions>(this OptionsBuilder<TOptions> builder, string sectionName)
+            where TOptions : class
+        {
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            Configure<TOptions>(builder.Services, name);
+            return builder;
+        }
+
+        /// <summary>
+        /// Registers a injected configuration service which TOptions will bind against.
+        /// </summary>
+        /// <typeparam name="TOptions">The type of options being configured.</typeparam>
+        /// <param name="builder">The <see cref="OptionsBuilder&lt;TOptions&gt;"/> to configure.</param>
+        /// <param name="configureBinder">Used to configure the <see cref="BinderOptions"/>.</param>
+        /// <returns>The <see cref="IServiceCollection"/> so that additional calls can be chained.</returns>
+        public static OptionsBuilder<TOptions> Configure<TOptions>(this OptionsBuilder<TOptions> builder, Action<BinderOptions> configureBinder)
+            where TOptions : class
+        {
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            return Configure(builder, Options.Options.DefaultName, configureBinder);
+        }
+
+        /// <summary>
+        /// Registers a injected configuration service which TOptions will bind against.
+        /// </summary>
+        /// <typeparam name="TOptions">The type of options being configured.</typeparam>
+        /// <param name="builder">The <see cref="OptionsBuilder&lt;TOptions&gt;"/> to configure.</param>
+        /// <param name="sectionName">The name of the options instance.</param>
+        /// <param name="configureBinder">Used to configure the <see cref="BinderOptions"/>.</param>
+        /// <returns>The <see cref="IServiceCollection"/> so that additional calls can be chained.</returns>
+        public static OptionsBuilder<TOptions> Configure<TOptions>(this OptionsBuilder<TOptions> builder, string sectionName, Action<BinderOptions> configureBinder)
+            where TOptions : class
+        {
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+
+            Configure<TOptions>(builder.Services, name, configureBinder);
+            return builder;
+        }
+    }
+}
+#endif

src/Protocol/LanguageProtocolDelegatingHandlers.cs

@@ -1088,6 +1088,17 @@ public NotificationCapability(Func<TParams, TCapability, Task> handler) :
             {
             }
 
+            public NotificationCapability(Action<TParams, TCapability, CancellationToken> handler) :
+                this(
+                    Guid.Empty, (request, capability, ct) => {
+                        handler(request, capability, ct);
+                        return Task.CompletedTask;
+                    }
+                )
+            {
+            }
+
+
             public NotificationCapability(Func<TParams, TCapability, CancellationToken, Task> handler) :
                 this(Guid.Empty, handler)
             {

src/Protocol/Protocol.csproj

@@ -9,6 +9,11 @@
 
     <ItemGroup>
         <PackageReference Include="Microsoft.Extensions.Configuration" />
+        <!--
+        TODO: Add these in a future version
+        <PackageReference Include="Microsoft.Extensions.Configuration.Binder" />
+        <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" />
+        -->
     </ItemGroup>
 
     <ItemGroup>

src/Protocol/Workspace/IDidChangeConfigurationHandler.cs

@@ -14,15 +14,16 @@ namespace OmniSharp.Extensions.LanguageServer.Protocol.Workspace
     [GenerateHandlerMethods]
     [GenerateRequestMethods(typeof(IWorkspaceLanguageClient), typeof(ILanguageClient))]
     public interface IDidChangeConfigurationHandler : IJsonRpcNotificationHandler<DidChangeConfigurationParams>,
-                                                      IRegistration<object>, ICapability<DidChangeConfigurationCapability>
+                                                      IRegistration<object>, // TODO: Remove this in the future
+                                                      ICapability<DidChangeConfigurationCapability>
     {
     }
 
     public abstract class DidChangeConfigurationHandler : IDidChangeConfigurationHandler
     {
-        public object GetRegistrationOptions() => new object();
         public abstract Task<Unit> Handle(DidChangeConfigurationParams request, CancellationToken cancellationToken);
         public virtual void SetCapability(DidChangeConfigurationCapability capability) => Capability = capability;
         protected DidChangeConfigurationCapability Capability { get; private set; } = null!;
+        public object GetRegistrationOptions() => new object();
     }
 }

src/Protocol/Workspace/IDidChangeWorkspaceFoldersHandler.cs

@@ -12,7 +12,8 @@ namespace OmniSharp.Extensions.LanguageServer.Protocol.Workspace
     [Method(WorkspaceNames.DidChangeWorkspaceFolders, Direction.ClientToServer)]
     [GenerateHandlerMethods]
     [GenerateRequestMethods(typeof(IWorkspaceLanguageClient), typeof(ILanguageClient))]
-    public interface IDidChangeWorkspaceFoldersHandler : IJsonRpcNotificationHandler<DidChangeWorkspaceFoldersParams>, IRegistration<object>
+    public interface IDidChangeWorkspaceFoldersHandler : IJsonRpcNotificationHandler<DidChangeWorkspaceFoldersParams>,
+                                                         IRegistration<object> // TODO: Remove this in the future
     {
     }