Clean up if an exception is thrown in the middle of ServerFactory.Start

src/Microsoft.AspNet.Server.Kestrel/ServerFactory.cs

@@ -36,13 +36,27 @@ namespace Microsoft.AspNet.Server.Kestrel
 
         public IDisposable Start(IFeatureCollection serverFeatures, Func<IFeatureCollection, Task> application)
         {
-            var disposables = new List<IDisposable>();
+            var disposables = new Stack<IDisposable>();
+            var disposer = new Disposable(() =>
+            {
+                foreach (var disposable in disposables)
+                {
+                    disposable.Dispose();
+                }
+            });
+
+            try
+            {
                 var information = (KestrelServerInformation)serverFeatures.Get<IKestrelServerInformation>();
                 var engine = new KestrelEngine(_libraryManager, _appShutdownService);
+
+                disposables.Push(engine);
+
                 engine.Start(information.ThreadCount == 0 ? 1 : information.ThreadCount);
+
                 foreach (var address in information.Addresses)
                 {
-                disposables.Add(engine.CreateServer(
+                    disposables.Push(engine.CreateServer(
                         address.Scheme,
                         address.Host,
                         address.Port,
@@ -52,14 +66,14 @@ namespace Microsoft.AspNet.Server.Kestrel
                             await application.Invoke(request.Features).ConfigureAwait(false);
                         }));
                 }
-            disposables.Add(engine);
+
-            return new Disposable(() =>
+                return disposer;
+            }
+            catch
             {
-                foreach (var disposable in disposables)
+                disposer.Dispose();
-                {
+                throw;
-                    disposable.Dispose();
+            }
-                }
-            });
         }
     }
 }