From 7e9de494b7ed80550843d294daa5836653149e3e Mon Sep 17 00:00:00 2001
From: Ben Adams <thundercat@illyriad.co.uk>
Date: Fri, 12 Jul 2019 21:47:32 +0200
Subject: [PATCH] Use task.IsCompletedSuccessfully rather than ReferenceEquals
 (#11606)

---
 .../src/Buffers/PagedBufferedTextWriter.cs          | 12 +++---------
 .../Kestrel/Core/src/Internal/Http/HttpProtocol.cs  | 13 +++++--------
 .../Internal/Infrastructure/KestrelConnection.cs    |  2 +-
 3 files changed, 9 insertions(+), 18 deletions(-)

diff --git a/src/Mvc/Mvc.ViewFeatures/src/Buffers/PagedBufferedTextWriter.cs b/src/Mvc/Mvc.ViewFeatures/src/Buffers/PagedBufferedTextWriter.cs
index 9c74598b24..611a03f45c 100644
--- a/src/Mvc/Mvc.ViewFeatures/src/Buffers/PagedBufferedTextWriter.cs
+++ b/src/Mvc/Mvc.ViewFeatures/src/Buffers/PagedBufferedTextWriter.cs
@@ -109,9 +109,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Buffers
         {
             var flushTask = FlushAsyncCore();
 
-            // FlushAsyncCore will return CompletedTask if nothing sync buffered
-            // Fast-path and skip async state-machine if only a single async operation
-            return ReferenceEquals(flushTask, Task.CompletedTask) ? 
+            return flushTask.IsCompletedSuccessfully ? 
                 _inner.WriteAsync(value) :
                 WriteAsyncAwaited(flushTask, value);
         }
@@ -126,9 +124,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Buffers
         {
             var flushTask = FlushAsyncCore();
 
-            // FlushAsyncCore will return CompletedTask if nothing sync buffered
-            // Fast-path and skip async state-machine if only a single async operation
-            return ReferenceEquals(flushTask, Task.CompletedTask) ?
+            return flushTask.IsCompletedSuccessfully ?
                 _inner.WriteAsync(buffer, index, count) :
                 WriteAsyncAwaited(flushTask, buffer, index, count);
         }
@@ -143,9 +139,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Buffers
         {
             var flushTask = FlushAsyncCore();
 
-            // FlushAsyncCore will return CompletedTask if nothing sync buffered
-            // Fast-path and skip async state-machine if only a single async operation
-            return ReferenceEquals(flushTask, Task.CompletedTask) ?
+            return flushTask.IsCompletedSuccessfully ?
                 _inner.WriteAsync(value) :
                 WriteAsyncAwaited(flushTask, value);
         }
diff --git a/src/Servers/Kestrel/Core/src/Internal/Http/HttpProtocol.cs b/src/Servers/Kestrel/Core/src/Internal/Http/HttpProtocol.cs
index ea0948d8e0..3f879207f2 100644
--- a/src/Servers/Kestrel/Core/src/Internal/Http/HttpProtocol.cs
+++ b/src/Servers/Kestrel/Core/src/Internal/Http/HttpProtocol.cs
@@ -767,7 +767,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
                 while (onStarting.TryPop(out var entry))
                 {
                     var task = entry.Key.Invoke(entry.Value);
-                    if (!ReferenceEquals(task, Task.CompletedTask))
+                    if (!task.IsCompletedSuccessfully)
                     {
                         return FireOnStartingAwaited(task, onStarting);
                     }
@@ -817,7 +817,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
                 try
                 {
                     var task = entry.Key.Invoke(entry.Value);
-                    if (!ReferenceEquals(task, Task.CompletedTask))
+                    if (!task.IsCompletedSuccessfully)
                     {
                         return FireOnCompletedAwaited(task, onCompleted);
                     }
@@ -953,8 +953,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         public Task InitializeResponseAsync(int firstWriteByteCount)
         {
             var startingTask = FireOnStarting();
-            // If return is Task.CompletedTask no awaiting is required
-            if (!ReferenceEquals(startingTask, Task.CompletedTask))
+            if (!startingTask.IsCompletedSuccessfully)
             {
                 return InitializeResponseAwaited(startingTask, firstWriteByteCount);
             }
@@ -1397,8 +1396,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             if (!HasResponseStarted)
             {
                 var initializeTask = InitializeResponseAsync(0);
-                // If return is Task.CompletedTask no awaiting is required
-                if (!ReferenceEquals(initializeTask, Task.CompletedTask))
+                if (!initializeTask.IsCompletedSuccessfully)
                 {
                     return FlushAsyncAwaited(initializeTask, cancellationToken);
                 }
@@ -1509,8 +1507,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             Debug.Assert(!HasResponseStarted);
 
             var startingTask = FireOnStarting();
-
-            if (!ReferenceEquals(startingTask, Task.CompletedTask))
+            if (!startingTask.IsCompletedSuccessfully)
             {
                 return FirstWriteAsyncAwaited(startingTask, data, cancellationToken);
             }
diff --git a/src/Servers/Kestrel/Core/src/Internal/Infrastructure/KestrelConnection.cs b/src/Servers/Kestrel/Core/src/Internal/Infrastructure/KestrelConnection.cs
index cfa274558c..9cbf8f12a1 100644
--- a/src/Servers/Kestrel/Core/src/Internal/Infrastructure/KestrelConnection.cs
+++ b/src/Servers/Kestrel/Core/src/Internal/Infrastructure/KestrelConnection.cs
@@ -107,7 +107,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure
                 try
                 {
                     var task = entry.Key.Invoke(entry.Value);
-                    if (!ReferenceEquals(task, Task.CompletedTask))
+                    if (!task.IsCompletedSuccessfully)
                     {
                         return CompleteAsyncAwaited(task, onCompleted);
                     }