#212 Check for duplicate Configure or ConfigureServices methods.

src/Microsoft.AspNet.Hosting/Startup/StartupLoader.cs

@@ -105,8 +105,23 @@ namespace Microsoft.AspNet.Hosting.Startup
         {
             var methodNameWithEnv = string.Format(CultureInfo.InvariantCulture, methodName, environmentName);
             var methodNameWithNoEnv = string.Format(CultureInfo.InvariantCulture, methodName, "");
-            var methodInfo = startupType.GetMethod(methodNameWithEnv, BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static)
+
-                ?? startupType.GetMethod(methodNameWithNoEnv, BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static);
+            var methods = startupType.GetMethods(BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static);
+            var selectedMethods = methods.Where(method => method.Name.Equals(methodNameWithEnv)).ToList();
+            if (selectedMethods.Count > 1)
+            {
+                throw new InvalidOperationException(string.Format("Having multiple overloads of method '{0}' is not supported.", methodNameWithEnv));
+            }
+            if (selectedMethods.Count == 0)
+            {
+                selectedMethods = methods.Where(method => method.Name.Equals(methodNameWithNoEnv)).ToList();
+                if (selectedMethods.Count > 1)
+                {
+                    throw new InvalidOperationException(string.Format("Having multiple overloads of method '{0}' is not supported.", methodNameWithNoEnv));
+                }
+            }
+
+            var methodInfo = selectedMethods.FirstOrDefault();
             if (methodInfo == null)
             {
                 if (required)

test/Microsoft.AspNet.Hosting.Tests/Fakes/StartupTwoConfigureServices.cs

@@ -0,0 +1,30 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNet.Builder;
+using Microsoft.Framework.DependencyInjection;
+
+namespace Microsoft.AspNet.Hosting.Fakes
+{
+    public class StartupTwoConfigureServices
+    {
+        public StartupTwoConfigureServices()
+        {
+        }
+
+        public void ConfigureServices(IServiceCollection services)
+        {
+
+        }
+
+        public void ConfigureServices(IServiceCollection services, object service)
+        {
+
+        }
+
+        public void Configure(IApplicationBuilder builder)
+        {
+
+        }
+    }
+}

test/Microsoft.AspNet.Hosting.Tests/Fakes/StartupTwoConfigures.cs

@@ -0,0 +1,24 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNet.Builder;
+
+namespace Microsoft.AspNet.Hosting.Fakes
+{
+    public class StartupTwoConfigures
+    {
+        public StartupTwoConfigures()
+        {
+        }
+
+        public void Configure(IApplicationBuilder builder)
+        {
+
+        }
+
+        public void Configure(IApplicationBuilder builder, object service)
+        {
+
+        }
+    }
+}

test/Microsoft.AspNet.Hosting.Tests/StartupManagerTests.cs

@@ -83,6 +83,38 @@ namespace Microsoft.AspNet.Hosting.Tests
             Assert.Equal("A method named 'ConfigureBoom' or 'Configure' in the type 'Microsoft.AspNet.Hosting.Fakes.StartupBoom' could not be found.", ex.Message);
         }
 
+        [Fact]
+        public void StartupWithTwoConfiguresThrows()
+        {
+            var serviceCollection = new ServiceCollection();
+            serviceCollection.AddInstance<IFakeStartupCallback>(this);
+            var services = serviceCollection.BuildServiceProvider();
+
+            var diagnosticMessages = new List<string>();
+            var hostingEnv = new HostingEnvironment { EnvironmentName = "TwoConfigures" };
+            var loader = new StartupLoader(services, hostingEnv);
+            var type = loader.FindStartupType("Microsoft.AspNet.Hosting.Tests", diagnosticMessages);
+
+            var ex = Assert.Throws<InvalidOperationException>(() => loader.LoadMethods(type, diagnosticMessages));
+            Assert.Equal("Having multiple overloads of method 'Configure' is not supported.", ex.Message);
+        }
+
+        [Fact]
+        public void StartupWithTwoConfigureServicesThrows()
+        {
+            var serviceCollection = new ServiceCollection();
+            serviceCollection.AddInstance<IFakeStartupCallback>(this);
+            var services = serviceCollection.BuildServiceProvider();
+
+            var diagnosticMessages = new List<string>();
+            var hostingEnv = new HostingEnvironment { EnvironmentName = "TwoConfigureServices" };
+            var loader = new StartupLoader(services, hostingEnv);
+            var type = loader.FindStartupType("Microsoft.AspNet.Hosting.Tests", diagnosticMessages);
+
+            var ex = Assert.Throws<InvalidOperationException>(() => loader.LoadMethods(type, diagnosticMessages));
+            Assert.Equal("Having multiple overloads of method 'ConfigureServices' is not supported.", ex.Message);
+        }
+
         [Fact]
         public void StartupClassCanHandleConfigureServicesThatReturnsNull()
         {