1.2.6: fix bug when targeting cluster on 4.0+

Directory.build.props

 <Project>
   <PropertyGroup>
-    <VersionPrefix>1.2.5</VersionPrefix>
+    <VersionPrefix>1.2.6</VersionPrefix>
 
     <Copyright>2017 Stack Exchange, Inc.</Copyright>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>

StackExchange.Redis/StackExchange/Redis/ClusterConfiguration.cs

@@ -182,8 +182,8 @@ internal ClusterConfiguration(ServerSelectionStrategy serverSelectionStrategy, s
                     if (string.IsNullOrWhiteSpace(line)) continue;
                     var node = new ClusterNode(this, line, origin);
                     
-                    // Be resilient to ":0 {master,slave},fail,noaddr" nodes
-                    if (node.IsNoAddr)
+                    // Be resilient to ":0 {master,slave},fail,noaddr" nodes, and nodes where the endpoint doesn't parse
+                    if (node.IsNoAddr || node.EndPoint == null)
                         continue;
 
                     // Override the origin value with the endpoint advertised with the target node to
@@ -309,7 +309,12 @@ internal ClusterNode(ClusterConfiguration configuration, string raw, EndPoint or
 
             var flags = parts[2].Split(StringSplits.Comma);
 
-            EndPoint = Format.TryParseEndPoint(parts[1]);
+            // redis 4 changes the format of "cluster nodes" - adds @... to the endpoint
+            var ep = parts[1];
+            int at = ep.IndexOf('@');
+            if (at >= 0) ep = ep.Substring(0, at);
+
+            EndPoint = Format.TryParseEndPoint(ep);
             if (flags.Contains("myself"))
             {
                 IsMyself = true;

docs/ReleaseNotes.md

@@ -2,6 +2,10 @@
 
 # Important: .NET 4.0 support is currently **disabled**; if you need .NET 4.0, please stick with 1.2.1 while we keep investigating
 
+## 1.2.6
+
+- fix change to `cluster nodes` output when using cluster-enabled target and 4.0+ (see [redis #4186]https://github.com/antirez/redis/issues/4186)
+
 ## 1.2.5
 
 - critical fix: "poll mode" was disabled in the build for net45/net60 - impact: IO jams and lack of reader during high load