alternative API: expose debug error in form of an exception

src/csharp/Grpc.Core.Api/Status.cs

@@ -14,6 +14,8 @@
 // limitations under the License.
 #endregion
 
+using System;
+
 namespace Grpc.Core
 {
     /// <summary>
@@ -47,12 +49,12 @@ namespace Grpc.Core
         /// </summary>
         /// <param name="statusCode">Status code.</param>
         /// <param name="detail">Detail.</param>
-        /// <param name="debugErrorString">Optional internal error string.</param>
+        /// <param name="debugErrorException">Optional internal error details.</param>
-        public Status(StatusCode statusCode, string detail, string debugErrorString)
+        public Status(StatusCode statusCode, string detail, Exception debugErrorException)
         {
             StatusCode = statusCode;
             Detail = detail;
-            DebugErrorString = debugErrorString;
+            DebugErrorException = debugErrorException;
         }
 
         /// <summary>
@@ -70,20 +72,20 @@ namespace Grpc.Core
         /// This field will be only populated on a client and its value is generated locally,
         /// based on the internal state of the gRPC client stack (i.e. the value is never sent over the wire).
         /// Note that this field is available only for debugging purposes, the application logic should
-        /// never rely on values of this field (it should should <c>StatusCode</c> and <c>Detail</c> instead).
+        /// never rely on values of this field (it should use <c>StatusCode</c> and <c>Detail</c> instead).
         /// Example: when a client fails to connect to a server, this field may provide additional details
         /// why the connection to the server has failed.
         /// </summary>
-        public string DebugErrorString { get; }
+        public Exception DebugErrorException { get; }
 
         /// <summary>
         /// Returns a <see cref="System.String"/> that represents the current <see cref="Grpc.Core.Status"/>.
         /// </summary>
         public override string ToString()
         {
-            if (DebugErrorString != null)
+            if (DebugErrorException != null)
             {
-                return $"Status(StatusCode=\"{StatusCode}\", Detail=\"{Detail}\", DebugErrorString=\"{DebugErrorString}\")";
+                return $"Status(StatusCode=\"{StatusCode}\", Detail=\"{Detail}\", DebugErrorException=\"{DebugErrorException}\")";
             }
             return $"Status(StatusCode=\"{StatusCode}\", Detail=\"{Detail}\")";
         }

src/csharp/Grpc.Core.Tests/ClientServerTest.cs

@@ -144,18 +144,18 @@ namespace Grpc.Core.Tests
         {
             helper.UnaryHandler = new UnaryServerMethod<string, string>((request, context) =>
             {
-                context.Status = new Status(StatusCode.Unauthenticated, "", "this DebugErrorString value should not be transmitted to the client");
+                context.Status = new Status(StatusCode.Unauthenticated, "", new DebugErrorException("this DebugErrorString value should not be transmitted to the client"));
                 return Task.FromResult("");
             });
 
             var ex = Assert.Throws<RpcException>(() => Calls.BlockingUnaryCall(helper.CreateUnaryCall(), "abc"));
             Assert.AreEqual(StatusCode.Unauthenticated, ex.Status.StatusCode);
-            StringAssert.Contains("Error received from peer", ex.Status.DebugErrorString, "Is \"Error received from peer\" still a valid substring to search for in the client-generated error message from C-core?");
+            StringAssert.Contains("Error received from peer", ex.Status.DebugErrorException.Message, "Is \"Error received from peer\" still a valid substring to search for in the client-generated error message from C-core?");
             Assert.AreEqual(0, ex.Trailers.Count);
 
             var ex2 = Assert.ThrowsAsync<RpcException>(async () => await Calls.AsyncUnaryCall(helper.CreateUnaryCall(), "abc"));
             Assert.AreEqual(StatusCode.Unauthenticated, ex2.Status.StatusCode);
-            StringAssert.Contains("Error received from peer", ex2.Status.DebugErrorString, "Is \"Error received from peer\" still a valid substring to search for in the client-generated error message from C-core?");
+            StringAssert.Contains("Error received from peer", ex2.Status.DebugErrorException.Message, "Is \"Error received from peer\" still a valid substring to search for in the client-generated error message from C-core?");
             Assert.AreEqual(0, ex2.Trailers.Count);
         }
 

src/csharp/Grpc.Core/Internal/BatchContextSafeHandle.cs

@@ -93,7 +93,7 @@ namespace Grpc.Core.Internal
             IntPtr detailsPtr = Native.grpcsharp_batch_context_recv_status_on_client_details(this, out detailsLength);
             string details = MarshalUtils.PtrToStringUTF8(detailsPtr, (int)detailsLength.ToUInt32());
             string debugErrorString = Marshal.PtrToStringAnsi(Native.grpcsharp_batch_context_recv_status_on_client_error_string(this));
-            var status = new Status(Native.grpcsharp_batch_context_recv_status_on_client_status(this), details, debugErrorString);
+            var status = new Status(Native.grpcsharp_batch_context_recv_status_on_client_status(this), details, debugErrorString != null ? new DebugErrorException(debugErrorString) : null);
 
             IntPtr metadataArrayPtr = Native.grpcsharp_batch_context_recv_status_on_client_trailing_metadata(this);
             var metadata = MetadataArraySafeHandle.ReadMetadataFromPtrUnsafe(metadataArrayPtr);

src/csharp/Grpc.Core/Internal/DebugErrorException.cs

@@ -0,0 +1,35 @@
+#region Copyright notice and license
+
+// Copyright 2019 The gRPC Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#endregion
+
+using System;
+using System.Runtime.InteropServices;
+using System.Threading;
+using Grpc.Core.Utils;
+
+namespace Grpc.Core.Internal
+{
+    /// <summary>
+    /// Represents error details provides by C-core's debug_error_string
+    /// </summary>
+    internal class DebugErrorException : Exception
+    {
+        public DebugErrorException(string message) : base(message)
+        {
+        }
+    }
+}