From 513f6ac8164e1b421f0122f9898a55222b71e843 Mon Sep 17 00:00:00 2001
From: Kristian Hellang <kristian@hellang.com>
Date: Fri, 23 Jun 2017 17:48:06 +0200
Subject: [PATCH] Avoid having to return anything in
 StartupBase.ConfigureServices (#957)

* Implement IStartup explicitly so we don't have to return a service provider
* Inherit StartupBase and override CreateServiceProvider
---
 .../SampleStartups/StartupBlockingOnStart.cs  |  3 +-
 .../Startup/StartupBase.cs                    | 32 +++++++++++--------
 2 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/samples/SampleStartups/StartupBlockingOnStart.cs b/samples/SampleStartups/StartupBlockingOnStart.cs
index c46010e18b..65a226f3cd 100644
--- a/samples/SampleStartups/StartupBlockingOnStart.cs
+++ b/samples/SampleStartups/StartupBlockingOnStart.cs
@@ -11,11 +11,10 @@ namespace SampleStartups
 {
     public class StartupBlockingOnStart : StartupBase
     {
-        public override IServiceProvider ConfigureServices(IServiceCollection services)
+        public override void ConfigureServices(IServiceCollection services)
         {
             // This method gets called by the runtime. Use this method to add services to the container.
             // For more information on how to configure your application, visit http://go.microsoft.com/fwlink/?LinkID=398940
-            return base.ConfigureServices(services);
         }
 
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
diff --git a/src/Microsoft.AspNetCore.Hosting/Startup/StartupBase.cs b/src/Microsoft.AspNetCore.Hosting/Startup/StartupBase.cs
index 83e65c8d9e..5a180ba9b4 100644
--- a/src/Microsoft.AspNetCore.Hosting/Startup/StartupBase.cs
+++ b/src/Microsoft.AspNetCore.Hosting/Startup/StartupBase.cs
@@ -11,36 +11,40 @@ namespace Microsoft.AspNetCore.Hosting
     {
         public abstract void Configure(IApplicationBuilder app);
 
-        public virtual IServiceProvider ConfigureServices(IServiceCollection services)
+        IServiceProvider IStartup.ConfigureServices(IServiceCollection services)
+        {
+            ConfigureServices(services);
+            return CreateServiceProvider(services);
+        }
+
+        public virtual void ConfigureServices(IServiceCollection services)
+        {
+        }
+
+        public virtual IServiceProvider CreateServiceProvider(IServiceCollection services)
         {
             return services.BuildServiceProvider();
         }
     }
 
-    public abstract class StartupBase<TContainerBuilder> : IStartup
+    public abstract class StartupBase<TBuilder> : StartupBase
     {
-        private readonly IServiceProviderFactory<TContainerBuilder> _factory;
+        private readonly IServiceProviderFactory<TBuilder> _factory;
 
-        public StartupBase(IServiceProviderFactory<TContainerBuilder> factory)
+        public StartupBase(IServiceProviderFactory<TBuilder> factory)
         {
             _factory = factory;
         }
 
-        public abstract void Configure(IApplicationBuilder app);
-
-        public virtual void ConfigureServices(IServiceCollection services)
+        public override IServiceProvider CreateServiceProvider(IServiceCollection services)
         {
-
-        }
-
-        IServiceProvider IStartup.ConfigureServices(IServiceCollection services)
-        {
-            ConfigureServices(services);
             var builder = _factory.CreateBuilder(services);
             ConfigureContainer(builder);
             return _factory.CreateServiceProvider(builder);
         }
 
-        public virtual void ConfigureContainer(TContainerBuilder containerBuilder) { }
+        public virtual void ConfigureContainer(TBuilder builder)
+        {
+        }
     }
 }
\ No newline at end of file