Fix: Rexpect backoff in the disconnect -> resurrection case as well (#2856)

Additional case handling for #2853, respecting backoff in the disconnected -> resurrecting state case. We need to check backoff in that flow as well to prevent a premature `TryConnect`.

Author: NickCraver

docs/ReleaseNotes.md

@@ -7,7 +7,7 @@ Current package versions:
 | [![StackExchange.Redis](https://img.shields.io/nuget/v/StackExchange.Redis.svg)](https://www.nuget.org/packages/StackExchange.Redis/) | [![StackExchange.Redis](https://img.shields.io/nuget/vpre/StackExchange.Redis.svg)](https://www.nuget.org/packages/StackExchange.Redis/) | [![StackExchange.Redis MyGet](https://img.shields.io/myget/stackoverflow/vpre/StackExchange.Redis.svg)](https://www.myget.org/feed/stackoverflow/package/nuget/StackExchange.Redis) |
 
 ## Unreleased
-- Fix: Respect `IReconnectRetryPolicy` timing in the case that a node that was present disconnects indefinitely ([#2853 by NickCraver](https://github.com/StackExchange/StackExchange.Redis/pull/2853))
+- Fix: Respect `IReconnectRetryPolicy` timing in the case that a node that was present disconnects indefinitely ([#2853](https://github.com/StackExchange/StackExchange.Redis/pull/2853) & [#2856](https://github.com/StackExchange/StackExchange.Redis/pull/2856) by NickCraver)
 - Changes max default retry policy backoff to 60 seconds ([#2853 by NickCraver](https://github.com/StackExchange/StackExchange.Redis/pull/2853))
 - Fix [#2652](https://github.com/StackExchange/StackExchange.Redis/issues/2652): Track client-initiated shutdown for any pipe type ([#2814 by bgrainger](https://github.com/StackExchange/StackExchange.Redis/pull/2814))
 

src/StackExchange.Redis/PhysicalBridge.cs

@@ -550,6 +550,12 @@ internal void OnFullyEstablished(PhysicalConnection connection, string source)
         private int connectStartTicks;
         private long connectTimeoutRetryCount = 0;
 
+        private bool DueForConnectRetry()
+        {
+            int connectTimeMilliseconds = unchecked(Environment.TickCount - Thread.VolatileRead(ref connectStartTicks));
+            return Multiplexer.RawConfig.ReconnectRetryPolicy.ShouldRetry(Interlocked.Read(ref connectTimeoutRetryCount), connectTimeMilliseconds);
+        }
+
         internal void OnHeartbeat(bool ifConnectedOnly)
         {
             bool runThisTime = false;
@@ -575,9 +581,7 @@ internal void OnHeartbeat(bool ifConnectedOnly)
                 switch (state)
                 {
                     case (int)State.Connecting:
-                        int connectTimeMilliseconds = unchecked(Environment.TickCount - Thread.VolatileRead(ref connectStartTicks));
-                        bool shouldRetry = Multiplexer.RawConfig.ReconnectRetryPolicy.ShouldRetry(Interlocked.Read(ref connectTimeoutRetryCount), connectTimeMilliseconds);
-                        if (shouldRetry)
+                        if (DueForConnectRetry())
                         {
                             Interlocked.Increment(ref connectTimeoutRetryCount);
                             var ex = ExceptionFactory.UnableToConnect(Multiplexer, "ConnectTimeout");
@@ -679,7 +683,7 @@ internal void OnHeartbeat(bool ifConnectedOnly)
                             shouldResetConnectionRetryCount = false;
                             Interlocked.Exchange(ref connectTimeoutRetryCount, 0);
                         }
-                        if (!ifConnectedOnly)
+                        if (!ifConnectedOnly && DueForConnectRetry())
                         {
                             Multiplexer.Trace("Resurrecting " + ToString());
                             Multiplexer.OnResurrecting(ServerEndPoint.EndPoint, ConnectionType);

tests/StackExchange.Redis.Tests/ConnectingFailDetectionTests.cs

@@ -18,6 +18,7 @@ public async Task FastNoticesFailOnConnectingSyncCompletion()
         try
         {
             using var conn = Create(keepAlive: 1, connectTimeout: 10000, allowAdmin: true, shared: false);
+            conn.RawConfig.ReconnectRetryPolicy = new LinearRetry(200);
 
             var db = conn.GetDatabase();
             db.Ping();
@@ -57,6 +58,7 @@ public async Task FastNoticesFailOnConnectingAsyncCompletion()
         try
         {
             using var conn = Create(keepAlive: 1, connectTimeout: 10000, allowAdmin: true, shared: false);
+            conn.RawConfig.ReconnectRetryPolicy = new LinearRetry(200);
 
             var db = conn.GetDatabase();
             db.Ping();