Imported Upstream version 5.4.0.167

Former-commit-id: 5624ac747d633e885131e8349322922b6a59baaa

mcs/class/referencesource/System.ServiceModel.Internals/System/Runtime/AsyncResult.cs

@@ -402,7 +402,7 @@ namespace System.Runtime
             return asyncResult;
         }
 
-        // can be utilized by subclasses to write core completion code for both the [....] and async paths
+        // can be utilized by subclasses to write core completion code for both the sync and async paths
         // in one location, signalling chainable synchronous completion with the boolean result,
         // and leveraging PrepareAsyncCompletion for conversion to an AsyncCallback.
         // NOTE: requires that "this" is passed in as the state object to the asynchronous sub-call being used with a completion routine.

mcs/class/referencesource/System.ServiceModel.Internals/System/Runtime/Diagnostics/DiagnosticTraceBase.cs

@@ -484,7 +484,7 @@ namespace System.Runtime.Diagnostics
                 {
                     OnShutdownTracing();
                 }
-#pragma warning suppress 56500 //[....]; Taken care of by FxCop
+#pragma warning suppress 56500 //Microsoft; Taken care of by FxCop
                 catch (Exception exception)
                 {
                     if (Fx.IsFatal(exception))

mcs/class/referencesource/System.ServiceModel.Internals/System/Runtime/Diagnostics/EtwDiagnosticTrace.cs

@@ -15,6 +15,7 @@ namespace System.Runtime.Diagnostics
     using System.Xml.XPath;
     using System.Diagnostics.CodeAnalysis;
     using System.Security.Permissions;
+    using System.ServiceModel.Internals;
     using System.Collections.Generic;
     using System.Collections.Concurrent;
 
@@ -29,6 +30,7 @@ namespace System.Runtime.Diagnostics
         const string DiagnosticTraceSource = "System.ServiceModel.Diagnostics";
 
         const int XmlBracketsLength = 5; // "<></>".Length;
+        const int XmlBracketsLengthForNullValue = 4; // "< />".Length; (Empty XML Element)
 
         static readonly public Guid ImmutableDefaultEtwProviderId = new Guid("{c651f5f6-1c0d-492e-8ae1-b4efd7c9d503}");
         [Fx.Tag.SecurityNote(Critical = "provider Id to create EtwProvider, which is SecurityCritical")]
@@ -891,7 +893,19 @@ namespace System.Runtime.Diagnostics
 
         static bool WriteXmlElementString(XmlTextWriter xml, string localName, string value, ref int remainingLength)
         {
-            int xmlElementLength = (localName.Length * 2) + EtwDiagnosticTrace.XmlBracketsLength + value.Length;
+            int xmlElementLength;
+
+            // Quirk to fix DevDiv 155469: All previous versions of that platform (up-to 4.6.2) will get the old behavior (throw null ref when Exception Message property is null) 
+            if (string.IsNullOrEmpty(value) && !LocalAppContextSwitches.IncludeNullExceptionMessageInETWTrace)
+            {
+                xmlElementLength = localName.Length + EtwDiagnosticTrace.XmlBracketsLengthForNullValue;
+            }
+
+            else
+            {
+                xmlElementLength = (localName.Length * 2) + EtwDiagnosticTrace.XmlBracketsLength + value.Length;
+            }
+                
             if (xmlElementLength <= remainingLength)
             {
                 xml.WriteElementString(localName, value);

mcs/class/referencesource/System.ServiceModel.Internals/System/Runtime/MruCache.cs

@@ -60,7 +60,7 @@ namespace System.Runtime
             Fx.Assert(null != key, "");
 
             // if anything goes wrong (duplicate entry, etc) we should 
-            // clear our caches so that we don't get out of [....]
+            // clear our caches so that we don't get out of sync
             bool success = false;
             try
             {

mcs/class/referencesource/System.ServiceModel.Internals/System/Runtime/ThreadNeutralSemaphore.cs

@@ -105,7 +105,7 @@ namespace System.Runtime
             {
                 if (!thisPtr.RemoveWaiter(data.Waiter))
                 {
-                    // The timeout ----d with Exit and exit won.
+                    // The timeout raced with Exit and exit won.
                     // We've successfully entered.
                     exceptionToPropagate = null;
                 }
@@ -160,7 +160,7 @@ namespace System.Runtime
 
                 if (timedOut && !RemoveWaiter(waiter))
                 {
-                    // The timeout ----d with Exit and exit won.
+                    // The timeout raced with Exit and exit won.
                     // We've successfully entered.
 
                     timedOut = false;

mcs/class/referencesource/System.ServiceModel.Internals/System/Runtime/TraceLevelHelper.cs

@@ -10,7 +10,7 @@ namespace System.Runtime
     using System.Diagnostics;
 
     /// <remarks>
-    /// [....] (11/15/10, CSDMain 194940) - Previously, this code first checked that the opcode was set to informational.  If not, it would check
+    /// Microsoft (11/15/10, CSDMain 194940) - Previously, this code first checked that the opcode was set to informational.  If not, it would check
     /// the opcode name for start, stop, suspend, or resume and use that or return Information otherwise.  This does not work well with the latest 
     /// ETW changes where almost every event has a task and opcode.  With the old logic, if an opcode is set on the event with a level such as 
     /// warning or error, the level would be incorrectly reported in diagnostic tracing as informational.  Also, start/stop/suspend/resume events