From 831785fe9fc4e3fd00889ce59b38c68a6c021a9a Mon Sep 17 00:00:00 2001
From: Ryan Nowak <nowakra@gmail.com>
Date: Wed, 8 Jul 2015 15:29:01 -0700
Subject: [PATCH] Make AddAuthorization() idempotent

Found this issue which looking into making AddMvc() idempotent. You'll end
up with multiple pass-through handlers registered if two components call
AddAuthorization(). This is very possible to happen if used two frameworks
in the same app.
---
 .../ServiceCollectionExtensions.cs                              | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Microsoft.AspNet.Authorization/ServiceCollectionExtensions.cs b/src/Microsoft.AspNet.Authorization/ServiceCollectionExtensions.cs
index 92f93fe1a3..d0a60edf2e 100644
--- a/src/Microsoft.AspNet.Authorization/ServiceCollectionExtensions.cs
+++ b/src/Microsoft.AspNet.Authorization/ServiceCollectionExtensions.cs
@@ -14,7 +14,7 @@ namespace Microsoft.Framework.DependencyInjection
         {
             services.AddOptions();
             services.TryAdd(ServiceDescriptor.Transient<IAuthorizationService, DefaultAuthorizationService>());
-            services.AddTransient<IAuthorizationHandler, PassThroughAuthorizationHandler>();
+            services.TryAddEnumerable(ServiceDescriptor.Transient<IAuthorizationHandler, PassThroughAuthorizationHandler>());
             return services;
         }