Improve detection and error message when bad auth; still need to see why it...

Improve detection and error message when bad auth; still need to see why it takes 5s to timeout in my shell, though

StackExchange.Redis.Tests/Secure.cs

@@ -88,7 +88,7 @@ public async Task ConnectWithWrongPassword(string password)
                 }
             }).ConfigureAwait(false);
             Output.WriteLine("Exception: " + ex.Message);
-            Assert.Equal("It was not possible to connect to the redis server(s); to create a disconnected multiplexer, disable AbortOnConnectFail. AuthenticationFailure on PING", ex.Message);
+            Assert.Equal("It was not possible to connect to the redis server(s). There was an authentication failure; check that passwords (or client certificates) are configured correctly.", ex.Message);
         }
     }
 }

StackExchange.Redis/StackExchange/Redis/ConnectionMultiplexer.cs

@@ -571,6 +571,9 @@ private static bool WaitAllIgnoreErrors(Task[] tasks, int timeout)
             return false;
         }
 
+        internal bool AuthSuspect { get; private set; }
+        internal void SetAuthSuspect() => AuthSuspect = true;
+
         private void LogLockedWithThreadPoolStats(TextWriter log, string message, out int busyWorkerCount)
         {
             busyWorkerCount = 0;
@@ -735,7 +738,7 @@ public static async Task<ConnectionMultiplexer> ConnectAsync(string configuratio
                 bool configured = await muxer.ReconfigureAsync(true, false, log, null, "connect").ObserveErrors().ForAwait();
                 if (!configured)
                 {
-                    throw ExceptionFactory.UnableToConnect(muxer.RawConfig.AbortOnConnectFail, muxer.failureMessage);
+                    throw ExceptionFactory.UnableToConnect(muxer, muxer.failureMessage);
                 }
                 killMe = null;
                 return muxer;
@@ -761,7 +764,7 @@ public static async Task<ConnectionMultiplexer> ConnectAsync(ConfigurationOption
                 bool configured = await muxer.ReconfigureAsync(true, false, log, null, "connect").ObserveErrors().ForAwait();
                 if (!configured)
                 {
-                    throw ExceptionFactory.UnableToConnect(muxer.RawConfig.AbortOnConnectFail, muxer.failureMessage);
+                    throw ExceptionFactory.UnableToConnect(muxer, muxer.failureMessage);
                 }
                 killMe = null;
                 return muxer;
@@ -828,14 +831,14 @@ private static ConnectionMultiplexer ConnectImpl(Func<ConnectionMultiplexer> mul
                     task.ObserveErrors();
                     if (muxer.RawConfig.AbortOnConnectFail)
                     {
-                        throw ExceptionFactory.UnableToConnect(muxer.RawConfig.AbortOnConnectFail, "ConnectTimeout");
+                        throw ExceptionFactory.UnableToConnect(muxer, "ConnectTimeout");
                     }
                     else
                     {
-                        muxer.LastException = ExceptionFactory.UnableToConnect(muxer.RawConfig.AbortOnConnectFail, "ConnectTimeout");
+                        muxer.LastException = ExceptionFactory.UnableToConnect(muxer, "ConnectTimeout");
                     }
                 }
-                if (!task.Result) throw ExceptionFactory.UnableToConnect(muxer.RawConfig.AbortOnConnectFail, muxer.failureMessage);
+                if (!task.Result) throw ExceptionFactory.UnableToConnect(muxer, muxer.failureMessage);
                 killMe = null;
                 return muxer;
             }

StackExchange.Redis/StackExchange/Redis/ExceptionFactory.cs

@@ -216,12 +216,17 @@ private static string GetLabel(bool includeDetail, string command, Message messa
         {
             return message == null ? command : (includeDetail ? message.CommandAndKey : message.Command.ToString());
         }
-
-        internal static Exception UnableToConnect(bool abortOnConnect, string failureMessage=null)
+        internal static Exception UnableToConnect(ConnectionMultiplexer muxer, string failureMessage=null)
+        {
+            var sb = new StringBuilder("It was not possible to connect to the redis server(s).");
+            if (muxer != null)
             {
-            var abortOnConnectionFailure = abortOnConnect ? "to create a disconnected multiplexer, disable AbortOnConnectFail. " : "";
-            return new RedisConnectionException(ConnectionFailureType.UnableToConnect,
-                string.Format("It was not possible to connect to the redis server(s); {0}{1}", abortOnConnectionFailure, failureMessage));
+                if (muxer.AuthSuspect) sb.Append(" There was an authentication failure; check that passwords (or client certificates) are configured correctly.");
+                else if (!muxer.RawConfig.AbortOnConnectFail) sb.Append(" To create a disconnected multiplexer, disable AbortOnConnectFail.");
+            }
+            if (!string.IsNullOrWhiteSpace(failureMessage)) sb.Append(" ").Append(failureMessage.Trim());
+
+            return new RedisConnectionException(ConnectionFailureType.UnableToConnect, sb.ToString());
         }
 
         internal static Exception BeganProfilingWithDuplicateContext(object forContext)

StackExchange.Redis/StackExchange/Redis/Message.cs

@@ -574,9 +574,9 @@ internal static CommandFlags SetMasterSlaveFlags(CommandFlags everything, Comman
                             | masterSlave;
         }
 
-        internal void Cancel()
+        internal void Cancel(Exception ex = null)
         {
-            resultProcessor?.SetException(this, new TaskCanceledException());
+            resultProcessor?.SetException(this, ex ?? new TaskCanceledException());
         }
 
         // true if ready to be completed (i.e. false if re-issued to another server)

StackExchange.Redis/StackExchange/Redis/PhysicalBridge.cs

@@ -45,7 +45,9 @@ internal sealed partial class PhysicalBridge : IDisposable
 
         private long profileLastLog;
         private int profileLogIndex;
+
         private volatile bool reportNextFailure = true, reconfigureNextFailure = false;
+        
         private volatile int state = (int)State.Disconnected;
 
         public PhysicalBridge(ServerEndPoint serverEndPoint, ConnectionType type)
@@ -275,6 +277,7 @@ internal void ResetNonConnected()
 
         internal void OnConnectionFailed(PhysicalConnection connection, ConnectionFailureType failureType, Exception innerException)
         {
+            AbandonPendingBacklog(innerException);
             if (reportNextFailure)
             {
                 LastException = innerException;
@@ -329,6 +332,15 @@ void WritePendingBacklog(PhysicalConnection connection)
                 } while (next != null);
             }
         }
+        void AbandonPendingBacklog(Exception ex)
+        {
+            Message next;
+            do
+            {
+                next = DequeueNextPendingBacklog();
+                next.Cancel(ex);
+            } while (next != null);
+        }
         internal void OnFullyEstablished(PhysicalConnection connection)
         {
             Trace("OnFullyEstablished");
@@ -372,7 +384,7 @@ internal void OnHeartbeat(bool ifConnectedOnly)
                         if (shouldRetry)
                         {
                             Interlocked.Increment(ref connectTimeoutRetryCount);
-                            LastException = ExceptionFactory.UnableToConnect(Multiplexer.RawConfig.AbortOnConnectFail, "ConnectTimeout");
+                            LastException = ExceptionFactory.UnableToConnect(Multiplexer, "ConnectTimeout");
                             Trace("Aborting connect");
                             // abort and reconnect
                             var snapshot = physical;

StackExchange.Redis/StackExchange/Redis/ResultProcessor.cs

@@ -107,7 +107,10 @@ public static readonly TimeSpanProcessor
             TimeSpanFromSeconds = new TimeSpanProcessor(false);
         public static readonly HashEntryArrayProcessor
             HashEntryArray = new HashEntryArrayProcessor();
-        private static readonly byte[] MOVED = Encoding.UTF8.GetBytes("MOVED "), ASK = Encoding.UTF8.GetBytes("ASK ");
+        private static readonly byte[]
+            MOVED = Encoding.UTF8.GetBytes("MOVED "),
+            ASK = Encoding.UTF8.GetBytes("ASK "),
+            NOAUTH = Encoding.UTF8.GetBytes("NOAUTH ");
 
         public void ConnectionFail(Message message, ConnectionFailureType fail, Exception innerException)
         {
@@ -147,6 +150,7 @@ public virtual bool SetResult(PhysicalConnection connection, Message message, Ra
             }
             if (result.IsError)
             {
+                if (result.AssertStarts(NOAUTH)) connection?.Multiplexer?.SetAuthSuspect();
                 var bridge = connection.Bridge;
                 var server = bridge.ServerEndPoint;
                 bool log = !message.IsInternalCall;
@@ -891,6 +895,7 @@ protected override bool SetResultCore(PhysicalConnection connection, Message mes
                     SetResult(message, true);
                     return true;
                 }
+                if(message.Command == RedisCommand.AUTH) connection?.Multiplexer?.SetAuthSuspect();
                 return false;
             }
         }

TestConsole/Program.cs

 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.IO;
 using System.IO.Pipelines;
 using System.Linq;
@@ -9,7 +10,8 @@ class Program
 {
     static int Main()
     {
-        //var s = new StringWriter();
+        var s = new StringWriter();
+        var watch = Stopwatch.StartNew();
         try
         {
 #if DEBUG
@@ -18,10 +20,11 @@ static int Main()
             
             var config = new ConfigurationOptions
             {
+                ConnectRetry = 0,
                 EndPoints = { "127.0.0.1:6381" },
                 Password = "abc",                
             };
-            using (var conn = ConnectionMultiplexer.Connect(config, log: Console.Out))
+            using (var conn = ConnectionMultiplexer.Connect(config, log: s))
             {
                 Execute(conn);
             }
@@ -35,9 +38,14 @@ static int Main()
         }
         finally
         {
+            watch.Stop();
             Console.WriteLine();
+            Console.WriteLine($"{watch.ElapsedMilliseconds}ms");
+            Console.WriteLine();
+
             //Console.WriteLine(s);
             Console.ReadKey();
+            
         }
     }