few small improvements

auth/conn_reauth_credentials_listener.go

@@ -1,6 +1,7 @@
 package auth
 
 import (
+	"runtime"
 	"time"
 
 	"github.com/redis/go-redis/v9/internal/pool"
@@ -47,12 +48,14 @@ func (c *ConnReAuthCredentialsListener) OnNext(credentials Credentials) {
 	// this is important because the connection pool may be in the process of reconnecting the connection
 	// and we don't want to interfere with that process
 	// but we also don't want to block for too long, so incorporate a timeout
+compandswap:
 	for !c.conn.Usable.CompareAndSwap(true, false) {
 		select {
 		case <-timeout:
 			err = pool.ErrConnUnusableTimeout
-			break
+			break compandswap
 		default:
+			runtime.Gosched()
 		}
 	}
 	if err != nil {
@@ -61,9 +64,7 @@ func (c *ConnReAuthCredentialsListener) OnNext(credentials Credentials) {
 	}
 	// we set the usable flag, so restore it back to usable after we're done
 	defer c.conn.SetUsable(true)
-
-	err = c.reAuth(c.conn, credentials)
-	if err != nil {
+	if err = c.reAuth(c.conn, credentials); err != nil {
 		c.OnError(err)
 	}
 }
@@ -94,6 +95,5 @@ func NewConnReAuthCredentialsListener(conn *pool.Conn, reAuth func(conn *pool.Co
 	}
 }
 
-
 // Ensure ConnReAuthCredentialsListener implements the CredentialsListener interface.
 var _ CredentialsListener = (*ConnReAuthCredentialsListener)(nil)

internal/pool/conn.go

@@ -456,15 +456,16 @@ func (cn *Conn) MarkQueuedForHandoff() error {
 	const maxRetries = 50
 	const baseDelay = time.Microsecond
 
+	connAquired := false
 	for attempt := 0; attempt < maxRetries; attempt++ {
 		// first we need to mark the connection as not usable
 		// to prevent the pool from returning it to the caller
-		if !cn.Usable.CompareAndSwap(true, false) {
+		if !connAquired && !cn.Usable.CompareAndSwap(true, false) {
 			continue
 		}
+		connAquired = true
 
 		currentState := cn.getHandoffState()
-
 		// Check if marked for handoff
 		if !currentState.ShouldHandoff {
 			return errors.New("connection was not marked for handoff")
@@ -479,6 +480,9 @@ func (cn *Conn) MarkQueuedForHandoff() error {
 
 		// Atomic compare-and-swap to update state
 		if cn.handoffStateAtomic.CompareAndSwap(currentState, newState) {
+			if connAquired {
+				cn.Usable.Store(true)
+			}
 			return nil
 		}
 

redis.go

@@ -322,7 +322,7 @@ func (c *baseClient) connReAuthCredentialsListener(poolCn *pool.Conn) (auth.Cred
 	// Design decision: The main case we expect the connection to be in a non-usable state is when it is being reconnected
 	// during a handoff from maintnotifications.
 	// Setting the checkUsableTimeout to the handoff timeout if maintnotifications are enabled
-	// the default timeout if no maintnotifications are disabled is going to be 1 second.
+	// the default timeout if no maintnotifications are disabled is going to PoolTimeout.
 	//
 	// Note: Due to the auto by default mode of MaintNotificationsConfig
 	// the timeout for the first connection will probably be the value of MaintNotificationsConfig.HandoffTimeout
@@ -330,6 +330,8 @@ func (c *baseClient) connReAuthCredentialsListener(poolCn *pool.Conn) (auth.Cred
 	// of enabling maintnotifications later.
 	if c.opt.MaintNotificationsConfig != nil && c.opt.MaintNotificationsConfig.Mode != maintnotifications.ModeDisabled {
 		newCredListener.SetCheckUsableTimeout(c.opt.MaintNotificationsConfig.HandoffTimeout)
+	} else {
+		newCredListener.SetCheckUsableTimeout(c.opt.PoolTimeout)
 	}
 	c.credListeners[poolCn] = newCredListener
 	return newCredListener, func() {