From 50ac454d8d8a1915188b2a4bb3fff3b81bf6c0cf Mon Sep 17 00:00:00 2001
From: Geoff Kizer <geoffrek@microsoft.com>
Date: Thu, 8 Oct 2020 08:59:08 -0700
Subject: [PATCH] fix issue with duplicate completion in MultipleConnectAsync
 (#43112)

Co-authored-by: Geoffrey Kizer <geoffrek@windows.microsoft.com>
---
 .../Net/Sockets/MultipleConnectAsync.cs       | 28 ++++++++++++-------
 .../Net/Sockets/SocketAsyncEventArgs.cs       | 11 ++++++--
 2 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/src/libraries/System.Net.Sockets/src/System/Net/Sockets/MultipleConnectAsync.cs b/src/libraries/System.Net.Sockets/src/System/Net/Sockets/MultipleConnectAsync.cs
index 33a54eb950a..ff10fb26745 100644
--- a/src/libraries/System.Net.Sockets/src/System/Net/Sockets/MultipleConnectAsync.cs
+++ b/src/libraries/System.Net.Sockets/src/System/Net/Sockets/MultipleConnectAsync.cs
@@ -151,7 +151,7 @@ private bool DoDnsCallback(IAsyncResult result, bool sync)
             }
             else if (!pending)
             {
-                return DoConnectCallback(_internalArgs!);
+                return DoConnectCallback(_internalArgs!, sync);
             }
             else
             {
@@ -161,13 +161,13 @@ private bool DoDnsCallback(IAsyncResult result, bool sync)
 
         private void InternalConnectCallback(object? sender, SocketAsyncEventArgs args)
         {
-            DoConnectCallback(args);
+            DoConnectCallback(args, false);
         }
 
         // Callback which fires when an internal connection attempt completes.
         // If it failed and there are more addresses to try, do it.
         // Returns true if the operation is pending, false if it completed synchronously.
-        private bool DoConnectCallback(SocketAsyncEventArgs args)
+        private bool DoConnectCallback(SocketAsyncEventArgs args, bool sync)
         {
             Exception? exception = null;
 
@@ -243,16 +243,14 @@ private bool DoConnectCallback(SocketAsyncEventArgs args)
                 }
             }
 
-            if (exception == null)
+            if (exception != null)
             {
-                Succeed();
+                return Fail(sync, exception);
             }
             else
             {
-                AsyncFail(exception);
+                return Succeed(sync);
             }
-
-            return false;
         }
 
         // Called to initiate a connection attempt to the next address in the list.
@@ -287,11 +285,21 @@ private bool DoConnectCallback(SocketAsyncEventArgs args)
 
         protected abstract void OnSucceed();
 
-        private void Succeed()
+        private bool Succeed(bool sync)
         {
             OnSucceed();
-            _userArgs!.FinishWrapperConnectSuccess(_internalArgs!.ConnectSocket, _internalArgs.BytesTransferred, _internalArgs.SocketFlags);
+
+            if (sync)
+            {
+                _userArgs!.FinishWrapperConnectSyncSuccess(_internalArgs!.ConnectSocket, _internalArgs.BytesTransferred, _internalArgs.SocketFlags);
+            }
+            else
+            {
+                _userArgs!.FinishWrapperConnectAsyncSuccess(_internalArgs!.ConnectSocket, _internalArgs.BytesTransferred, _internalArgs.SocketFlags);
+            }
+
             _internalArgs.Dispose();
+            return !sync;
         }
 
         protected abstract void OnFail(bool abortive);
diff --git a/src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketAsyncEventArgs.cs b/src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketAsyncEventArgs.cs
index c6e77b34601..e85bb70d701 100644
--- a/src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketAsyncEventArgs.cs
+++ b/src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketAsyncEventArgs.cs
@@ -676,7 +676,7 @@ internal void FinishConnectByNameAsyncFailure(Exception exception, int bytesTran
             }
         }
 
-        internal void FinishWrapperConnectSuccess(Socket? connectSocket, int bytesTransferred, SocketFlags flags)
+        internal void FinishWrapperConnectSyncSuccess(Socket? connectSocket, int bytesTransferred, SocketFlags flags)
         {
             SetResults(SocketError.Success, bytesTransferred, flags);
             _currentSocket = connectSocket;
@@ -685,8 +685,15 @@ internal void FinishWrapperConnectSuccess(Socket? connectSocket, int bytesTransf
             if (SocketsTelemetry.Log.IsEnabled()) LogBytesTransferEvents(connectSocket?.SocketType, SocketAsyncOperation.Connect, bytesTransferred);
 
             // Complete the operation and raise the event.
-            ExecutionContext? context = _context; // store context before it's cleared as part of completing the operation
             Complete();
+        }
+
+        internal void FinishWrapperConnectAsyncSuccess(Socket? connectSocket, int bytesTransferred, SocketFlags flags)
+        {
+            ExecutionContext? context = _context; // store context before it's cleared as part of completing the operation
+
+            FinishWrapperConnectSyncSuccess(connectSocket, bytesTransferred, flags);
+
             if (context == null)
             {
                 OnCompletedInternal();
-- 
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