address pr comments

internal/auth/streaming/conn_reauth_credentials_listener.go

@@ -27,11 +27,7 @@ type ConnReAuthCredentialsListener struct {
 // It calls the reAuth function with the new credentials.
 // If the reAuth function returns an error, it calls the onErr function with the error.
 func (c *ConnReAuthCredentialsListener) OnNext(credentials auth.Credentials) {
-	if c.conn.IsClosed() {
+	if c.conn == nil || c.conn.IsClosed() || c.manager == nil || c.reAuth == nil {
-		return
-	}
-
-	if c.reAuth == nil {
 		return
 	}
 
@@ -41,17 +37,20 @@ func (c *ConnReAuthCredentialsListener) OnNext(credentials auth.Credentials) {
 	// The connection pool hook will re-authenticate the connection when it is
 	// returned to the pool in a clean, idle state.
 	c.manager.MarkForReAuth(c.conn, func(err error) {
+		// err is from connection acquisition (timeout, etc.)
 		if err != nil {
+			// Log the error
 			c.OnError(err)
 			return
 		}
+		// err is from reauth command execution
 		err = c.reAuth(c.conn, credentials)
 		if err != nil {
+			// Log the error
 			c.OnError(err)
 			return
 		}
 	})
-
 }
 
 // OnError is called when an error occurs.

internal/auth/streaming/manager.go

@@ -15,11 +15,13 @@ type Manager struct {
 }
 
 func NewManager(pl pool.Pooler, reAuthTimeout time.Duration) *Manager {
-	return &Manager{
+	m := &Manager{
 		pool:                 pl,
 		poolHookRef:          NewReAuthPoolHook(pl.Size(), reAuthTimeout),
 		credentialsListeners: NewCredentialsListeners(),
 	}
+	m.poolHookRef.manager = m
+	return m
 }
 
 func (m *Manager) PoolHook() pool.PoolHook {
@@ -35,6 +37,10 @@ func (m *Manager) Listener(
 		return nil, errors.New("poolCn cannot be nil")
 	}
 	connID := poolCn.GetID()
+	// if we reconnect the underlying network connection, the streaming credentials listener will continue to work
+	// so we can get the old listener from the cache and use it.
+
+	// subscribing the same (an already subscribed) listener for a StreamingCredentialsProvider SHOULD be a no-op
 	listener, ok := m.credentialsListeners.Get(connID)
 	if !ok || listener == nil {
 		newCredListener := &ConnReAuthCredentialsListener{
@@ -54,3 +60,7 @@ func (m *Manager) MarkForReAuth(poolCn *pool.Conn, reAuthFn func(error)) {
 	connID := poolCn.GetID()
 	m.poolHookRef.MarkForReAuth(connID, reAuthFn)
 }
+
+func (m *Manager) RemoveListener(connID uint64) {
+	m.credentialsListeners.Remove(connID)
+}

internal/auth/streaming/pool_hook.go

@@ -5,6 +5,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/redis/go-redis/v9/internal"
 	"github.com/redis/go-redis/v9/internal/pool"
 )
 
@@ -17,6 +18,9 @@ type ReAuthPoolHook struct {
 	// conn id -> bool
 	scheduledReAuth map[uint64]bool
 	scheduledLock   sync.RWMutex
+
+	// for cleanup
+	manager *Manager
 }
 
 func NewReAuthPoolHook(poolSize int, reAuthTimeout time.Duration) *ReAuthPoolHook {
@@ -32,7 +36,6 @@ func NewReAuthPoolHook(poolSize int, reAuthTimeout time.Duration) *ReAuthPoolHoo
 		workers:         workers,
 		reAuthTimeout:   reAuthTimeout,
 	}
-
 }
 
 func (r *ReAuthPoolHook) MarkForReAuth(connID uint64, reAuthFn func(error)) {
@@ -41,27 +44,22 @@ func (r *ReAuthPoolHook) MarkForReAuth(connID uint64, reAuthFn func(error)) {
 	r.shouldReAuth[connID] = reAuthFn
 }
 
-func (r *ReAuthPoolHook) ClearReAuthMark(connID uint64) {
-	r.shouldReAuthLock.Lock()
-	defer r.shouldReAuthLock.Unlock()
-	delete(r.shouldReAuth, connID)
-}
-
 func (r *ReAuthPoolHook) OnGet(_ context.Context, conn *pool.Conn, _ bool) (accept bool, err error) {
+	connID := conn.GetID()
 	r.shouldReAuthLock.RLock()
-	_, ok := r.shouldReAuth[conn.GetID()]
+	_, shouldReAuth := r.shouldReAuth[connID]
 	r.shouldReAuthLock.RUnlock()
 	// This connection was marked for reauth while in the pool,
 	// reject the connection
-	if ok {
+	if shouldReAuth {
 		// simply reject the connection, it will be re-authenticated in OnPut
 		return false, nil
 	}
 	r.scheduledLock.RLock()
-	hasScheduled, ok := r.scheduledReAuth[conn.GetID()]
+	_, hasScheduled := r.scheduledReAuth[connID]
 	r.scheduledLock.RUnlock()
 	// has scheduled reauth, reject the connection
-	if ok && hasScheduled {
+	if hasScheduled {
 		// simply reject the connection, it currently has a reauth scheduled
 		// and the worker is waiting for slot to execute the reauth
 		return false, nil
@@ -70,22 +68,38 @@ func (r *ReAuthPoolHook) OnGet(_ context.Context, conn *pool.Conn, _ bool) (acce
 }
 
 func (r *ReAuthPoolHook) OnPut(_ context.Context, conn *pool.Conn) (bool, bool, error) {
+	if conn == nil {
+		// noop
+		return true, false, nil
+	}
+	connID := conn.GetID()
 	// Check if reauth is needed and get the function with proper locking
 	r.shouldReAuthLock.RLock()
-	reAuthFn, ok := r.shouldReAuth[conn.GetID()]
+	r.scheduledLock.RLock()
+	reAuthFn, ok := r.shouldReAuth[connID]
 	r.shouldReAuthLock.RUnlock()
 
 	if ok {
+		r.shouldReAuthLock.Lock()
 		r.scheduledLock.Lock()
-		r.scheduledReAuth[conn.GetID()] = true
+		r.scheduledReAuth[connID] = true
+		delete(r.shouldReAuth, connID)
 		r.scheduledLock.Unlock()
-		// Clear the mark immediately to prevent duplicate reauth attempts
+		r.shouldReAuthLock.Unlock()
-		r.ClearReAuthMark(conn.GetID())
 		go func() {
 			<-r.workers
+			// safety first
+			if conn == nil || (conn != nil && conn.IsClosed()) {
+				r.workers <- struct{}{}
+				return
+			}
 			defer func() {
+				if rec := recover(); rec != nil {
+					// once again - safety first
+					internal.Logger.Printf(context.Background(), "panic in reauth worker: %v", rec)
+				}
 				r.scheduledLock.Lock()
-				delete(r.scheduledReAuth, conn.GetID())
+				delete(r.scheduledReAuth, connID)
 				r.scheduledLock.Unlock()
 				r.workers <- struct{}{}
 			}()
@@ -96,7 +110,7 @@ func (r *ReAuthPoolHook) OnPut(_ context.Context, conn *pool.Conn) (bool, bool,
 			// Try to acquire the connection
 			// We need to ensure the connection is both Usable and not Used
 			// to prevent data races with concurrent operations
-			const baseDelay = time.Microsecond
+			const baseDelay = 10 * time.Microsecond
 			acquired := false
 			attempt := 0
 			for !acquired {
@@ -108,36 +122,33 @@ func (r *ReAuthPoolHook) OnPut(_ context.Context, conn *pool.Conn) (bool, bool,
 					return
 				default:
 					// Try to acquire: set Usable=false, then check Used
-					if conn.Usable.CompareAndSwap(true, false) {
+					if conn.CompareAndSwapUsable(true, false) {
-						if !conn.Used.Load() {
+						if !conn.IsUsed() {
 							acquired = true
 						} else {
 							// Release Usable and retry with exponential backoff
-							conn.Usable.Store(true)
+							// todo(ndyakov): think of a better way to do this without the need
-							if attempt > 0 {
+							// to release the connection, but just wait till it is not used
-								// Exponential backoff: 1, 2, 4, 8... up to 512 microseconds
+							conn.SetUsable(true)
-								delay := baseDelay * time.Duration(1<<uint(attempt%10)) // Cap exponential growth
-								time.Sleep(delay)
-							}
-							attempt++
-						}
-					} else {
-						// Connection not usable, retry with exponential backoff
-						if attempt > 0 {
-							// Exponential backoff: 1, 2, 4, 8... up to 512 microseconds
-							delay := baseDelay * time.Duration(1<<uint(attempt%10)) // Cap exponential growth
-							time.Sleep(delay)
 						}
+					}
+					if !acquired {
+						// Exponential backoff: 10, 20, 40, 80... up to 5120 microseconds
+						delay := baseDelay * time.Duration(1<<uint(attempt%10)) // Cap exponential growth
+						time.Sleep(delay)
 						attempt++
 					}
 				}
 			}
 
-			// Successfully acquired the connection, perform reauth
+			// safety first
-			reAuthFn(nil)
+			if !conn.IsClosed() {
+				// Successfully acquired the connection, perform reauth
+				reAuthFn(nil)
+			}
 
 			// Release the connection
-			conn.Usable.Store(true)
+			conn.SetUsable(true)
 		}()
 	}
 
@@ -147,10 +158,16 @@ func (r *ReAuthPoolHook) OnPut(_ context.Context, conn *pool.Conn) (bool, bool,
 }
 
 func (r *ReAuthPoolHook) OnRemove(_ context.Context, conn *pool.Conn, _ error) {
+	connID := conn.GetID()
+	r.shouldReAuthLock.Lock()
 	r.scheduledLock.Lock()
-	delete(r.scheduledReAuth, conn.GetID())
+	delete(r.scheduledReAuth, connID)
+	delete(r.shouldReAuth, connID)
 	r.scheduledLock.Unlock()
-	r.ClearReAuthMark(conn.GetID())
+	r.shouldReAuthLock.Unlock()
+	if r.manager != nil {
+		r.manager.RemoveListener(connID)
+	}
 }
 
 var _ pool.PoolHook = (*ReAuthPoolHook)(nil)

internal/pool/conn.go

@@ -68,15 +68,15 @@ type Conn struct {
 	// is not in use. That way, the connection won't be used to send multiple commands at the same time and
 	// potentially corrupt the command stream.
 
-	// Usable flag to mark connection as safe for use
+	// usable flag to mark connection as safe for use
 	// It is false before initialization and after a handoff is marked
 	// It will be false during other background operations like re-authentication
-	Usable atomic.Bool
+	usable atomic.Bool
 
-	// Used flag to mark connection as used when a command is going to be
+	// used flag to mark connection as used when a command is going to be
 	// processed on that connection. This is used to prevent a race condition with
 	// background operations that may execute commands, like re-authentication.
-	Used atomic.Bool
+	used atomic.Bool
 
 	// Inited flag to mark connection as initialized, this is almost the same as usable
 	// but it is used to make sure we don't initialize a network connection twice
@@ -142,7 +142,7 @@ func NewConnWithBufferSize(netConn net.Conn, readBufSize, writeBufSize int) *Con
 	cn.netConnAtomic.Store(&atomicNetConn{conn: netConn})
 
 	// Initialize atomic state
-	cn.Usable.Store(false)           // false initially, set to true after initialization
+	cn.usable.Store(false)           // false initially, set to true after initialization
 	cn.handoffRetriesAtomic.Store(0) // 0 initially
 
 	// Initialize handoff state atomically
@@ -167,6 +167,42 @@ func (cn *Conn) SetUsedAt(tm time.Time) {
 	atomic.StoreInt64(&cn.usedAt, tm.Unix())
 }
 
+// Usable
+
+// CompareAndSwapUsable atomically compares and swaps the usable flag (lock-free).
+func (cn *Conn) CompareAndSwapUsable(old, new bool) bool {
+	return cn.usable.CompareAndSwap(old, new)
+}
+
+// IsUsable returns true if the connection is safe to use for new commands (lock-free).
+func (cn *Conn) IsUsable() bool {
+	return cn.usable.Load()
+}
+
+// SetUsable sets the usable flag for the connection (lock-free).
+// prefer CompareAndSwapUsable() when possible
+func (cn *Conn) SetUsable(usable bool) {
+	cn.usable.Store(usable)
+}
+
+// Used
+
+// CompareAndSwapUsed atomically compares and swaps the used flag (lock-free).
+func (cn *Conn) CompareAndSwapUsed(old, new bool) bool {
+	return cn.used.CompareAndSwap(old, new)
+}
+
+// IsUsed returns true if the connection is currently in use (lock-free).
+func (cn *Conn) IsUsed() bool {
+	return cn.used.Load()
+}
+
+// SetUsed sets the used flag for the connection (lock-free).
+// prefer CompareAndSwapUsed() when possible
+func (cn *Conn) SetUsed(val bool) {
+	cn.used.Store(val)
+}
+
 // getNetConn returns the current network connection using atomic load (lock-free).
 // This is the fast path for accessing netConn without mutex overhead.
 func (cn *Conn) getNetConn() net.Conn {
@@ -184,18 +220,6 @@ func (cn *Conn) setNetConn(netConn net.Conn) {
 	cn.netConnAtomic.Store(&atomicNetConn{conn: netConn})
 }
 
-// Lock-free helper methods for handoff state management
-
-// isUsable returns true if the connection is safe to use (lock-free).
-func (cn *Conn) isUsable() bool {
-	return cn.Usable.Load()
-}
-
-// setUsable sets the usable flag atomically (lock-free).
-func (cn *Conn) setUsable(usable bool) {
-	cn.Usable.Store(usable)
-}
-
 // getHandoffState returns the current handoff state atomically (lock-free).
 func (cn *Conn) getHandoffState() *HandoffState {
 	state := cn.handoffStateAtomic.Load()
@@ -240,11 +264,6 @@ func (cn *Conn) incrementHandoffRetries(delta int) int {
 	return int(cn.handoffRetriesAtomic.Add(uint32(delta)))
 }
 
-// IsUsable returns true if the connection is safe to use for new commands (lock-free).
-func (cn *Conn) IsUsable() bool {
-	return cn.isUsable()
-}
-
 // IsPooled returns true if the connection is managed by a pool and will be pooled on Put.
 func (cn *Conn) IsPooled() bool {
 	return cn.pooled
@@ -259,11 +278,6 @@ func (cn *Conn) IsInited() bool {
 	return cn.Inited.Load()
 }
 
-// SetUsable sets the usable flag for the connection (lock-free).
-func (cn *Conn) SetUsable(usable bool) {
-	cn.setUsable(usable)
-}
-
 // SetRelaxedTimeout sets relaxed timeouts for this connection during maintenanceNotifications upgrades.
 // These timeouts will be used for all subsequent commands until the deadline expires.
 // Uses atomic operations for lock-free access.
@@ -494,11 +508,10 @@ func (cn *Conn) MarkQueuedForHandoff() error {
 		// first we need to mark the connection as not usable
 		// to prevent the pool from returning it to the caller
 		if !connAcquired {
-			if cn.Usable.CompareAndSwap(true, false) {
+			if !cn.usable.CompareAndSwap(true, false) {
-				connAcquired = true
-			} else {
 				continue
 			}
+			connAcquired = true
 		}
 
 		currentState := cn.getHandoffState()
@@ -568,7 +581,7 @@ func (cn *Conn) ClearHandoffState() {
 	cn.setHandoffState(cleanState)
 	cn.setHandoffRetries(0)
 	// Clearing handoff state also means the connection is usable again
-	cn.setUsable(true)
+	cn.SetUsable(true)
 }
 
 // IncrementAndGetHandoffRetries atomically increments and returns handoff retries (lock-free).

internal/pool/hooks.go

@@ -22,7 +22,13 @@ type PoolHook interface {
 	OnPut(ctx context.Context, conn *Conn) (shouldPool bool, shouldRemove bool, err error)
 
 	// OnRemove is called when a connection is removed from the pool.
-	// It can be used for cleanup or logging purposes.
+	// This happens when:
+	// - Connection fails health check
+	// - Connection exceeds max lifetime
+	// - Pool is being closed
+	// - Connection encounters an error
+	// Implementations should clean up any per-connection state.
+	// The reason parameter indicates why the connection was removed.
 	OnRemove(ctx context.Context, conn *Conn, reason error)
 }
 

internal/pool/pool.go

@@ -435,7 +435,8 @@ func (p *ConnPool) getConn(ctx context.Context) (*Conn, error) {
 	now := time.Now()
 	attempts := 0
 
-	// get hooks manager
+	// Get hooks manager once for this getConn call for performance.
+	// Note: Hooks added/removed during this call won't be reflected.
 	p.hookManagerMu.RLock()
 	hookManager := p.hookManager
 	p.hookManagerMu.RUnlock()
@@ -580,11 +581,12 @@ func (p *ConnPool) popIdle() (*Conn, error) {
 		}
 		attempts++
 
-		if cn.IsUsable() {
+		if cn.CompareAndSwapUsed(false, true) {
-			if cn.Used.CompareAndSwap(false, true) {
+			if cn.IsUsable() {
 				p.idleConnsLen.Add(-1)
 				break
 			}
+			cn.SetUsed(false)
 		}
 
 		// Connection is not usable, put it back in the pool
@@ -679,10 +681,9 @@ func (p *ConnPool) Put(ctx context.Context, cn *Conn) {
 		shouldCloseConn = true
 	}
 
-	// Mark connection as not used only
+	// if the connection is not going to be closed, mark it as not used
-	// if it's not being closed
 	if !shouldCloseConn {
-		cn.Used.Store(false)
+		cn.SetUsed(false)
 	}
 
 	p.freeTurn()

internal/pool/pool_single.go

@@ -28,30 +28,30 @@ func (p *SingleConnPool) CloseConn(cn *Conn) error {
 	return p.pool.CloseConn(cn)
 }
 
-func (p *SingleConnPool) Get(ctx context.Context) (*Conn, error) {
+func (p *SingleConnPool) Get(_ context.Context) (*Conn, error) {
 	if p.stickyErr != nil {
 		return nil, p.stickyErr
 	}
 	if p.cn == nil {
 		return nil, ErrClosed
 	}
-	p.cn.Used.Store(true)
+	p.cn.SetUsed(true)
 	p.cn.SetUsedAt(time.Now())
 	return p.cn, nil
 }
 
-func (p *SingleConnPool) Put(ctx context.Context, cn *Conn) {
+func (p *SingleConnPool) Put(_ context.Context, cn *Conn) {
 	if p.cn == nil {
 		return
 	}
 	if p.cn != cn {
 		return
 	}
-	p.cn.Used.Store(false)
+	p.cn.SetUsed(false)
 }
 
-func (p *SingleConnPool) Remove(ctx context.Context, cn *Conn, reason error) {
+func (p *SingleConnPool) Remove(_ context.Context, cn *Conn, reason error) {
-	cn.Used.Store(false)
+	cn.SetUsed(false)
 	p.cn = nil
 	p.stickyErr = reason
 }
@@ -76,6 +76,6 @@ func (p *SingleConnPool) Stats() *Stats {
 	return &Stats{}
 }
 
-func (p *SingleConnPool) AddPoolHook(hook PoolHook) {}
+func (p *SingleConnPool) AddPoolHook(_ PoolHook) {}
 
-func (p *SingleConnPool) RemovePoolHook(hook PoolHook) {}
+func (p *SingleConnPool) RemovePoolHook(_ PoolHook) {}

maintnotifications/handoff_worker.go

@@ -481,7 +481,10 @@ func (hwm *handoffWorkerManager) closeConnFromRequest(ctx context.Context, reque
 			internal.Logger.Printf(ctx, logs.RemovingConnectionFromPool(conn.GetID(), err))
 		}
 	} else {
-		conn.Close()
+		err := conn.Close() // Close the connection if no pool provided
+		if err != nil {
+			internal.Logger.Printf(ctx, "redis: failed to close connection: %v", err)
+		}
 		if internal.LogLevel.WarnOrAbove() {
 			internal.Logger.Printf(ctx, logs.NoPoolProvidedCannotRemove(conn.GetID(), err))
 		}

redis.go

@@ -513,7 +513,7 @@ func (c *baseClient) initConn(ctx context.Context, cn *pool.Conn) error {
 	// mark the connection as usable and inited
 	// once returned to the pool as idle, this connection can be used by other clients
 	cn.SetUsable(true)
-	cn.Used.Store(false)
+	cn.SetUsed(false)
 	cn.Inited.Store(true)
 
 	// Set the connection initialization function for potential reconnections