Port #1434 to main

Fixes #1441

Reference:
* #1434
* #1438

Port changes from #1443

Author: lukebakken

projects/RabbitMQ.Client/client/api/ShutdownEventArgs.cs

@@ -41,11 +41,14 @@ namespace RabbitMQ.Client
     /// </remarks>
     public class ShutdownEventArgs : EventArgs
     {
+        private readonly Exception _exception;
+
         /// <summary>
         /// Construct a <see cref="ShutdownEventArgs"/> with the given parameters and
         ///  0 for <see cref="ClassId"/> and <see cref="MethodId"/>.
         /// </summary>
-        public ShutdownEventArgs(ShutdownInitiator initiator, ushort replyCode, string replyText, object cause = null)
+        public ShutdownEventArgs(ShutdownInitiator initiator, ushort replyCode, string replyText,
+            object cause = null)
             : this(initiator, replyCode, replyText, 0, 0, cause)
         {
         }
@@ -64,6 +67,26 @@ public ShutdownEventArgs(ShutdownInitiator initiator, ushort replyCode, string r
             Cause = cause;
         }
 
+        /// <summary>
+        /// Construct a <see cref="ShutdownEventArgs"/> with the given parameters.
+        /// </summary>
+        public ShutdownEventArgs(ShutdownInitiator initiator, ushort replyCode, string replyText, Exception exception)
+            : this(initiator, replyCode, replyText, 0, 0)
+        {
+            _exception = exception ?? throw new ArgumentNullException(nameof(exception));
+        }
+
+        /// <summary>
+        /// Exception causing the shutdown, or null if none.
+        /// </summary>
+        public Exception Exception
+        {
+            get
+            {
+                return _exception;
+            }
+        }
+
         /// <summary>
         /// Object causing the shutdown, or null if none.
         /// </summary>
@@ -104,7 +127,8 @@ public override string ToString()
                 + (ReplyText != null ? $", text='{ReplyText}'" : string.Empty)
                 + $", classId={ClassId}"
                 + $", methodId={MethodId}"
-                + (Cause != null ? $", cause={Cause}" : string.Empty);
+                + (Cause != null ? $", cause={Cause}" : string.Empty)
+                + (_exception != null ? $", exception={_exception}" : string.Empty);
         }
     }
 }

projects/RabbitMQ.Client/client/impl/ChannelBase.cs

@@ -50,6 +50,7 @@ internal abstract class ChannelBase : IChannel, IRecoverable
         ///<summary>Only used to kick-start a connection open
         ///sequence. See <see cref="Connection.OpenAsync"/> </summary>
         internal TaskCompletionSource<ConnectionStartDetails> m_connectionStartCell;
+        private Exception m_connectionStartException = null;
 
         // AMQP only allows one RPC operation to be active at a time. 
         protected readonly SemaphoreSlim _rpcSemaphore = new SemaphoreSlim(1, 1);
@@ -171,6 +172,16 @@ public IBasicConsumer DefaultConsumer
 
         public ISession Session { get; private set; }
 
+        public Exception ConnectionStartException => m_connectionStartException;
+
+        public void MaybeSetConnectionStartException(Exception ex)
+        {
+            if (m_connectionStartCell != null)
+            {
+                m_connectionStartException = ex;
+            }
+        }
+
         protected void TakeOver(ChannelBase other)
         {
             _basicAcksWrapper.Takeover(other._basicAcksWrapper);

projects/RabbitMQ.Client/client/impl/Connection.Commands.cs

@@ -81,7 +81,8 @@ await _frameHandler.SendProtocolHeaderAsync()
 
             if (connectionStart is null)
             {
-                throw new IOException("connection.start was never received, likely due to a network timeout");
+                const string msg = "connection.start was never received, likely due to a network timeout";
+                throw new IOException(msg, _channel0.ConnectionStartException);
             }
 
             ServerProperties = connectionStart.m_serverProperties;

projects/RabbitMQ.Client/client/impl/Connection.Receive.cs

@@ -53,16 +53,34 @@ await ReceiveLoop()
             catch (EndOfStreamException eose)
             {
                 // Possible heartbeat exception
-                HandleMainLoopException(new ShutdownEventArgs(ShutdownInitiator.Library, 0, "End of stream", eose));
+                var ea = new ShutdownEventArgs(ShutdownInitiator.Library,
+                    0, "End of stream",
+                    exception: eose);
+                HandleMainLoopException(ea);
             }
             catch (HardProtocolException hpe)
             {
                 await HardProtocolExceptionHandler(hpe)
                     .ConfigureAwait(false);
             }
+            catch (FileLoadException fileLoadException)
+            {
+                /*
+                 * https://github.com/rabbitmq/rabbitmq-dotnet-client/issues/1434
+                 * Ensure that these exceptions eventually make it to application code
+                 */
+                var ea = new ShutdownEventArgs(ShutdownInitiator.Library,
+                    Constants.InternalError, fileLoadException.Message,
+                    exception: fileLoadException);
+                HandleMainLoopException(ea);
+            }
             catch (Exception ex)
             {
-                HandleMainLoopException(new ShutdownEventArgs(ShutdownInitiator.Library, Constants.InternalError, "Unexpected Exception", ex));
+                var ea = new ShutdownEventArgs(ShutdownInitiator.Library,
+                    Constants.InternalError,
+                    $"Unexpected Exception: {ex.Message}",
+                    exception: ex);
+                HandleMainLoopException(ea);
             }
 
             FinishClose();
@@ -146,15 +164,17 @@ private void HandleMainLoopException(ShutdownEventArgs reason)
         {
             if (!SetCloseReason(reason))
             {
-                // TODO reason.Cause could be an Exception, should we use that?
-                LogCloseError("Unexpected Main Loop Exception while closing: " + reason, new Exception(reason.ToString()));
+                LogCloseError($"Unexpected Main Loop Exception while closing: {reason}", reason.Exception);
                 return;
             }
 
+            _channel0.MaybeSetConnectionStartException(reason.Exception);
+
             OnShutdown(reason);
-            LogCloseError($"Unexpected connection closure: {reason}", new Exception(reason.ToString()));
+            LogCloseError($"Unexpected connection closure: {reason}", reason.Exception);
         }
 
+        // TODO rename Async, add cancellation token?
         private async Task HardProtocolExceptionHandler(HardProtocolException hpe)
         {
             if (SetCloseReason(hpe.ShutdownReason))

projects/Test/Unit/APIApproval.Approve.verified.txt

@@ -787,10 +787,12 @@ namespace RabbitMQ.Client
     }
     public class ShutdownEventArgs : System.EventArgs
     {
+        public ShutdownEventArgs(RabbitMQ.Client.ShutdownInitiator initiator, ushort replyCode, string replyText, System.Exception exception) { }
         public ShutdownEventArgs(RabbitMQ.Client.ShutdownInitiator initiator, ushort replyCode, string replyText, object cause = null) { }
         public ShutdownEventArgs(RabbitMQ.Client.ShutdownInitiator initiator, ushort replyCode, string replyText, ushort classId, ushort methodId, object cause = null) { }
         public object Cause { get; }
         public ushort ClassId { get; }
+        public System.Exception Exception { get; }
         public RabbitMQ.Client.ShutdownInitiator Initiator { get; }
         public ushort MethodId { get; }
         public ushort ReplyCode { get; }