[CLIENT-3894] Setting user-agent allows a closed connection to return for tend

Also retracts the client versions with that bug.

Author: khaf

go.mod

@@ -24,3 +24,7 @@ require (
 	golang.org/x/tools v0.31.0 // indirect
 	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 )
+
+retract (
+	[v8.3.0, v8.4.1] // Problem with User Agent code returning a closed connection without an error.
+)

node.go

@@ -527,12 +527,11 @@ func (nd *Node) newTendConnection() (*Connection, Error) {
 		return nil, err
 	}
 
-	serverMinVersion, _ := version.Parse("8.1.0.0")
+	serverMinVersion := &version.Version{Major: 8, Minor: 1, Patch: 0, Build: 0}
 	if nd.version.IsGreaterOrEqual(serverMinVersion) {
 		if err := nd.sendUserAgentId(conn); err != nil {
-			// If setting user agent failed, we still return the connection
-			// as it is already authenticated and usable.
 			logger.Logger.Warn("Error setting user agent for node %s: %s", nd.String(), err.Error())
+			return nil, err
 		}
 	}