[Vendor] Update go-redis to v8.5.0 (#13749)

* Update go-redis to v8.4.0

* github.com/go-redis/redis/v8  v8.4.0 -> v8.5.0

* Apply suggestions from code review

Co-authored-by: zeripath <art27@cantab.net>

* TODO

* Use the Queue termination channel as the default context for pushes

Signed-off-by: Andrew Thornton <art27@cantab.net>

* missed one

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: zeripath <art27@cantab.net>

vendor/github.com/go-redis/redis/v8/internal/pool/conn.go

@@ -0,0 +1,136 @@
+package pool
+
+import (
+	"bufio"
+	"context"
+	"net"
+	"sync/atomic"
+	"time"
+
+	"github.com/go-redis/redis/v8/internal"
+	"github.com/go-redis/redis/v8/internal/proto"
+	"go.opentelemetry.io/otel/trace"
+)
+
+var noDeadline = time.Time{}
+
+type Conn struct {
+	usedAt  int64 // atomic
+	netConn net.Conn
+
+	rd *proto.Reader
+	bw *bufio.Writer
+	wr *proto.Writer
+
+	Inited    bool
+	pooled    bool
+	createdAt time.Time
+}
+
+func NewConn(netConn net.Conn) *Conn {
+	cn := &Conn{
+		netConn:   netConn,
+		createdAt: time.Now(),
+	}
+	cn.rd = proto.NewReader(netConn)
+	cn.bw = bufio.NewWriter(netConn)
+	cn.wr = proto.NewWriter(cn.bw)
+	cn.SetUsedAt(time.Now())
+	return cn
+}
+
+func (cn *Conn) UsedAt() time.Time {
+	unix := atomic.LoadInt64(&cn.usedAt)
+	return time.Unix(unix, 0)
+}
+
+func (cn *Conn) SetUsedAt(tm time.Time) {
+	atomic.StoreInt64(&cn.usedAt, tm.Unix())
+}
+
+func (cn *Conn) SetNetConn(netConn net.Conn) {
+	cn.netConn = netConn
+	cn.rd.Reset(netConn)
+	cn.bw.Reset(netConn)
+}
+
+func (cn *Conn) Write(b []byte) (int, error) {
+	return cn.netConn.Write(b)
+}
+
+func (cn *Conn) RemoteAddr() net.Addr {
+	if cn.netConn != nil {
+		return cn.netConn.RemoteAddr()
+	}
+	return nil
+}
+
+func (cn *Conn) WithReader(ctx context.Context, timeout time.Duration, fn func(rd *proto.Reader) error) error {
+	return internal.WithSpan(ctx, "redis.with_reader", func(ctx context.Context, span trace.Span) error {
+		if err := cn.netConn.SetReadDeadline(cn.deadline(ctx, timeout)); err != nil {
+			return internal.RecordError(ctx, span, err)
+		}
+		if err := fn(cn.rd); err != nil {
+			return internal.RecordError(ctx, span, err)
+		}
+		return nil
+	})
+}
+
+func (cn *Conn) WithWriter(
+	ctx context.Context, timeout time.Duration, fn func(wr *proto.Writer) error,
+) error {
+	return internal.WithSpan(ctx, "redis.with_writer", func(ctx context.Context, span trace.Span) error {
+		if err := cn.netConn.SetWriteDeadline(cn.deadline(ctx, timeout)); err != nil {
+			return internal.RecordError(ctx, span, err)
+		}
+
+		if cn.bw.Buffered() > 0 {
+			cn.bw.Reset(cn.netConn)
+		}
+
+		if err := fn(cn.wr); err != nil {
+			return internal.RecordError(ctx, span, err)
+		}
+
+		if err := cn.bw.Flush(); err != nil {
+			return internal.RecordError(ctx, span, err)
+		}
+
+		internal.WritesCounter.Add(ctx, 1)
+
+		return nil
+	})
+}
+
+func (cn *Conn) Close() error {
+	return cn.netConn.Close()
+}
+
+func (cn *Conn) deadline(ctx context.Context, timeout time.Duration) time.Time {
+	tm := time.Now()
+	cn.SetUsedAt(tm)
+
+	if timeout > 0 {
+		tm = tm.Add(timeout)
+	}
+
+	if ctx != nil {
+		deadline, ok := ctx.Deadline()
+		if ok {
+			if timeout == 0 {
+				return deadline
+			}
+			if deadline.Before(tm) {
+				return deadline
+			}
+			return tm
+		}
+	}
+
+	if timeout > 0 {
+		return tm
+	}
+
+	return noDeadline
+}

vendor/github.com/go-redis/redis/v8/internal/pool/pool.go

@@ -0,0 +1,525 @@
+package pool
+
+import (
+	"context"
+	"errors"
+	"net"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/go-redis/redis/v8/internal"
+)
+
+var (
+	ErrClosed      = errors.New("redis: client is closed")
+	ErrPoolTimeout = errors.New("redis: connection pool timeout")
+)
+
+var timers = sync.Pool{
+	New: func() interface{} {
+		t := time.NewTimer(time.Hour)
+		t.Stop()
+		return t
+	},
+}
+
+// Stats contains pool state information and accumulated stats.
+type Stats struct {
+	Hits     uint32 // number of times free connection was found in the pool
+	Misses   uint32 // number of times free connection was NOT found in the pool
+	Timeouts uint32 // number of times a wait timeout occurred
+
+	TotalConns uint32 // number of total connections in the pool
+	IdleConns  uint32 // number of idle connections in the pool
+	StaleConns uint32 // number of stale connections removed from the pool
+}
+
+type Pooler interface {
+	NewConn(context.Context) (*Conn, error)
+	CloseConn(*Conn) error
+
+	Get(context.Context) (*Conn, error)
+	Put(context.Context, *Conn)
+	Remove(context.Context, *Conn, error)
+
+	Len() int
+	IdleLen() int
+	Stats() *Stats
+
+	Close() error
+}
+
+type Options struct {
+	Dialer  func(context.Context) (net.Conn, error)
+	OnClose func(*Conn) error
+
+	PoolSize           int
+	MinIdleConns       int
+	MaxConnAge         time.Duration
+	PoolTimeout        time.Duration
+	IdleTimeout        time.Duration
+	IdleCheckFrequency time.Duration
+}
+
+type lastDialErrorWrap struct {
+	err error
+}
+
+type ConnPool struct {
+	opt *Options
+
+	dialErrorsNum uint32 // atomic
+
+	lastDialError atomic.Value
+
+	queue chan struct{}
+
+	connsMu      sync.Mutex
+	conns        []*Conn
+	idleConns    []*Conn
+	poolSize     int
+	idleConnsLen int
+
+	stats Stats
+
+	_closed  uint32 // atomic
+	closedCh chan struct{}
+}
+
+var _ Pooler = (*ConnPool)(nil)
+
+func NewConnPool(opt *Options) *ConnPool {
+	p := &ConnPool{
+		opt: opt,
+
+		queue:     make(chan struct{}, opt.PoolSize),
+		conns:     make([]*Conn, 0, opt.PoolSize),
+		idleConns: make([]*Conn, 0, opt.PoolSize),
+		closedCh:  make(chan struct{}),
+	}
+
+	p.connsMu.Lock()
+	p.checkMinIdleConns()
+	p.connsMu.Unlock()
+
+	if opt.IdleTimeout > 0 && opt.IdleCheckFrequency > 0 {
+		go p.reaper(opt.IdleCheckFrequency)
+	}
+
+	return p
+}
+
+func (p *ConnPool) checkMinIdleConns() {
+	if p.opt.MinIdleConns == 0 {
+		return
+	}
+	for p.poolSize < p.opt.PoolSize && p.idleConnsLen < p.opt.MinIdleConns {
+		p.poolSize++
+		p.idleConnsLen++
+		go func() {
+			err := p.addIdleConn()
+			if err != nil {
+				p.connsMu.Lock()
+				p.poolSize--
+				p.idleConnsLen--
+				p.connsMu.Unlock()
+			}
+		}()
+	}
+}
+
+func (p *ConnPool) addIdleConn() error {
+	cn, err := p.dialConn(context.TODO(), true)
+	if err != nil {
+		return err
+	}
+
+	p.connsMu.Lock()
+	p.conns = append(p.conns, cn)
+	p.idleConns = append(p.idleConns, cn)
+	p.connsMu.Unlock()
+	return nil
+}
+
+func (p *ConnPool) NewConn(ctx context.Context) (*Conn, error) {
+	return p.newConn(ctx, false)
+}
+
+func (p *ConnPool) newConn(ctx context.Context, pooled bool) (*Conn, error) {
+	cn, err := p.dialConn(ctx, pooled)
+	if err != nil {
+		return nil, err
+	}
+
+	p.connsMu.Lock()
+	p.conns = append(p.conns, cn)
+	if pooled {
+		// If pool is full remove the cn on next Put.
+		if p.poolSize >= p.opt.PoolSize {
+			cn.pooled = false
+		} else {
+			p.poolSize++
+		}
+	}
+	p.connsMu.Unlock()
+
+	return cn, nil
+}
+
+func (p *ConnPool) dialConn(ctx context.Context, pooled bool) (*Conn, error) {
+	if p.closed() {
+		return nil, ErrClosed
+	}
+
+	if atomic.LoadUint32(&p.dialErrorsNum) >= uint32(p.opt.PoolSize) {
+		return nil, p.getLastDialError()
+	}
+
+	netConn, err := p.opt.Dialer(ctx)
+	if err != nil {
+		p.setLastDialError(err)
+		if atomic.AddUint32(&p.dialErrorsNum, 1) == uint32(p.opt.PoolSize) {
+			go p.tryDial()
+		}
+		return nil, err
+	}
+
+	internal.NewConnectionsCounter.Add(ctx, 1)
+	cn := NewConn(netConn)
+	cn.pooled = pooled
+	return cn, nil
+}
+
+func (p *ConnPool) tryDial() {
+	for {
+		if p.closed() {
+			return
+		}
+
+		conn, err := p.opt.Dialer(context.Background())
+		if err != nil {
+			p.setLastDialError(err)
+			time.Sleep(time.Second)
+			continue
+		}
+
+		atomic.StoreUint32(&p.dialErrorsNum, 0)
+		_ = conn.Close()
+		return
+	}
+}
+
+func (p *ConnPool) setLastDialError(err error) {
+	p.lastDialError.Store(&lastDialErrorWrap{err: err})
+}
+
+func (p *ConnPool) getLastDialError() error {
+	err, _ := p.lastDialError.Load().(*lastDialErrorWrap)
+	if err != nil {
+		return err.err
+	}
+	return nil
+}
+
+// Get returns existed connection from the pool or creates a new one.
+func (p *ConnPool) Get(ctx context.Context) (*Conn, error) {
+	if p.closed() {
+		return nil, ErrClosed
+	}
+
+	err := p.waitTurn(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	for {
+		p.connsMu.Lock()
+		cn := p.popIdle()
+		p.connsMu.Unlock()
+
+		if cn == nil {
+			break
+		}
+
+		if p.isStaleConn(cn) {
+			_ = p.CloseConn(cn)
+			continue
+		}
+
+		atomic.AddUint32(&p.stats.Hits, 1)
+		return cn, nil
+	}
+
+	atomic.AddUint32(&p.stats.Misses, 1)
+
+	newcn, err := p.newConn(ctx, true)
+	if err != nil {
+		p.freeTurn()
+		return nil, err
+	}
+
+	return newcn, nil
+}
+
+func (p *ConnPool) getTurn() {
+	p.queue <- struct{}{}
+}
+
+func (p *ConnPool) waitTurn(ctx context.Context) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+
+	select {
+	case p.queue <- struct{}{}:
+		return nil
+	default:
+	}
+
+	timer := timers.Get().(*time.Timer)
+	timer.Reset(p.opt.PoolTimeout)
+
+	select {
+	case <-ctx.Done():
+		if !timer.Stop() {
+			<-timer.C
+		}
+		timers.Put(timer)
+		return ctx.Err()
+	case p.queue <- struct{}{}:
+		if !timer.Stop() {
+			<-timer.C
+		}
+		timers.Put(timer)
+		return nil
+	case <-timer.C:
+		timers.Put(timer)
+		atomic.AddUint32(&p.stats.Timeouts, 1)
+		return ErrPoolTimeout
+	}
+}
+
+func (p *ConnPool) freeTurn() {
+	<-p.queue
+}
+
+func (p *ConnPool) popIdle() *Conn {
+	if len(p.idleConns) == 0 {
+		return nil
+	}
+
+	idx := len(p.idleConns) - 1
+	cn := p.idleConns[idx]
+	p.idleConns = p.idleConns[:idx]
+	p.idleConnsLen--
+	p.checkMinIdleConns()
+	return cn
+}
+
+func (p *ConnPool) Put(ctx context.Context, cn *Conn) {
+	if cn.rd.Buffered() > 0 {
+		internal.Logger.Printf(ctx, "Conn has unread data")
+		p.Remove(ctx, cn, BadConnError{})
+		return
+	}
+
+	if !cn.pooled {
+		p.Remove(ctx, cn, nil)
+		return
+	}
+
+	p.connsMu.Lock()
+	p.idleConns = append(p.idleConns, cn)
+	p.idleConnsLen++
+	p.connsMu.Unlock()
+	p.freeTurn()
+}
+
+func (p *ConnPool) Remove(ctx context.Context, cn *Conn, reason error) {
+	p.removeConnWithLock(cn)
+	p.freeTurn()
+	_ = p.closeConn(cn)
+}
+
+func (p *ConnPool) CloseConn(cn *Conn) error {
+	p.removeConnWithLock(cn)
+	return p.closeConn(cn)
+}
+
+func (p *ConnPool) removeConnWithLock(cn *Conn) {
+	p.connsMu.Lock()
+	p.removeConn(cn)
+	p.connsMu.Unlock()
+}
+
+func (p *ConnPool) removeConn(cn *Conn) {
+	for i, c := range p.conns {
+		if c == cn {
+			p.conns = append(p.conns[:i], p.conns[i+1:]...)
+			if cn.pooled {
+				p.poolSize--
+				p.checkMinIdleConns()
+			}
+			return
+		}
+	}
+}
+
+func (p *ConnPool) closeConn(cn *Conn) error {
+	if p.opt.OnClose != nil {
+		_ = p.opt.OnClose(cn)
+	}
+	return cn.Close()
+}
+
+// Len returns total number of connections.
+func (p *ConnPool) Len() int {
+	p.connsMu.Lock()
+	n := len(p.conns)
+	p.connsMu.Unlock()
+	return n
+}
+
+// IdleLen returns number of idle connections.
+func (p *ConnPool) IdleLen() int {
+	p.connsMu.Lock()
+	n := p.idleConnsLen
+	p.connsMu.Unlock()
+	return n
+}
+
+func (p *ConnPool) Stats() *Stats {
+	idleLen := p.IdleLen()
+	return &Stats{
+		Hits:     atomic.LoadUint32(&p.stats.Hits),
+		Misses:   atomic.LoadUint32(&p.stats.Misses),
+		Timeouts: atomic.LoadUint32(&p.stats.Timeouts),
+
+		TotalConns: uint32(p.Len()),
+		IdleConns:  uint32(idleLen),
+		StaleConns: atomic.LoadUint32(&p.stats.StaleConns),
+	}
+}
+
+func (p *ConnPool) closed() bool {
+	return atomic.LoadUint32(&p._closed) == 1
+}
+
+func (p *ConnPool) Filter(fn func(*Conn) bool) error {
+	p.connsMu.Lock()
+	defer p.connsMu.Unlock()
+
+	var firstErr error
+	for _, cn := range p.conns {
+		if fn(cn) {
+			if err := p.closeConn(cn); err != nil && firstErr == nil {
+				firstErr = err
+			}
+		}
+	}
+	return firstErr
+}
+
+func (p *ConnPool) Close() error {
+	if !atomic.CompareAndSwapUint32(&p._closed, 0, 1) {
+		return ErrClosed
+	}
+	close(p.closedCh)
+
+	var firstErr error
+	p.connsMu.Lock()
+	for _, cn := range p.conns {
+		if err := p.closeConn(cn); err != nil && firstErr == nil {
+			firstErr = err
+		}
+	}
+	p.conns = nil
+	p.poolSize = 0
+	p.idleConns = nil
+	p.idleConnsLen = 0
+	p.connsMu.Unlock()
+
+	return firstErr
+}
+
+func (p *ConnPool) reaper(frequency time.Duration) {
+	ticker := time.NewTicker(frequency)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ticker.C:
+			// It is possible that ticker and closedCh arrive together,
+			// and select pseudo-randomly pick ticker case, we double
+			// check here to prevent being executed after closed.
+			if p.closed() {
+				return
+			}
+			_, err := p.ReapStaleConns()
+			if err != nil {
+				internal.Logger.Printf(context.Background(), "ReapStaleConns failed: %s", err)
+				continue
+			}
+		case <-p.closedCh:
+			return
+		}
+	}
+}
+
+func (p *ConnPool) ReapStaleConns() (int, error) {
+	var n int
+	for {
+		p.getTurn()
+
+		p.connsMu.Lock()
+		cn := p.reapStaleConn()
+		p.connsMu.Unlock()
+
+		p.freeTurn()
+
+		if cn != nil {
+			_ = p.closeConn(cn)
+			n++
+		} else {
+			break
+		}
+	}
+	atomic.AddUint32(&p.stats.StaleConns, uint32(n))
+	return n, nil
+}
+
+func (p *ConnPool) reapStaleConn() *Conn {
+	if len(p.idleConns) == 0 {
+		return nil
+	}
+
+	cn := p.idleConns[0]
+	if !p.isStaleConn(cn) {
+		return nil
+	}
+
+	p.idleConns = append(p.idleConns[:0], p.idleConns[1:]...)
+	p.idleConnsLen--
+	p.removeConn(cn)
+
+	return cn
+}
+
+func (p *ConnPool) isStaleConn(cn *Conn) bool {
+	if p.opt.IdleTimeout == 0 && p.opt.MaxConnAge == 0 {
+		return false
+	}
+
+	now := time.Now()
+	if p.opt.IdleTimeout > 0 && now.Sub(cn.UsedAt()) >= p.opt.IdleTimeout {
+		return true
+	}
+	if p.opt.MaxConnAge > 0 && now.Sub(cn.createdAt) >= p.opt.MaxConnAge {
+		return true
+	}
+
+	return false
+}

vendor/github.com/go-redis/redis/v8/internal/pool/pool_single.go

@@ -0,0 +1,58 @@
+package pool
+
+import "context"
+
+type SingleConnPool struct {
+	pool      Pooler
+	cn        *Conn
+	stickyErr error
+}
+
+var _ Pooler = (*SingleConnPool)(nil)
+
+func NewSingleConnPool(pool Pooler, cn *Conn) *SingleConnPool {
+	return &SingleConnPool{
+		pool: pool,
+		cn:   cn,
+	}
+}
+
+func (p *SingleConnPool) NewConn(ctx context.Context) (*Conn, error) {
+	return p.pool.NewConn(ctx)
+}
+
+func (p *SingleConnPool) CloseConn(cn *Conn) error {
+	return p.pool.CloseConn(cn)
+}
+
+func (p *SingleConnPool) Get(ctx context.Context) (*Conn, error) {
+	if p.stickyErr != nil {
+		return nil, p.stickyErr
+	}
+	return p.cn, nil
+}
+
+func (p *SingleConnPool) Put(ctx context.Context, cn *Conn) {}
+
+func (p *SingleConnPool) Remove(ctx context.Context, cn *Conn, reason error) {
+	p.cn = nil
+	p.stickyErr = reason
+}
+
+func (p *SingleConnPool) Close() error {
+	p.cn = nil
+	p.stickyErr = ErrClosed
+	return nil
+}
+
+func (p *SingleConnPool) Len() int {
+	return 0
+}
+
+func (p *SingleConnPool) IdleLen() int {
+	return 0
+}
+
+func (p *SingleConnPool) Stats() *Stats {
+	return &Stats{}
+}

vendor/github.com/go-redis/redis/v8/internal/pool/pool_sticky.go

@@ -0,0 +1,202 @@
+package pool
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync/atomic"
+)
+
+const (
+	stateDefault = 0
+	stateInited  = 1
+	stateClosed  = 2
+)
+
+type BadConnError struct {
+	wrapped error
+}
+
+var _ error = (*BadConnError)(nil)
+
+func (e BadConnError) Error() string {
+	s := "redis: Conn is in a bad state"
+	if e.wrapped != nil {
+		s += ": " + e.wrapped.Error()
+	}
+	return s
+}
+
+func (e BadConnError) Unwrap() error {
+	return e.wrapped
+}
+
+//------------------------------------------------------------------------------
+
+type StickyConnPool struct {
+	pool   Pooler
+	shared int32 // atomic
+
+	state uint32 // atomic
+	ch    chan *Conn
+
+	_badConnError atomic.Value
+}
+
+var _ Pooler = (*StickyConnPool)(nil)
+
+func NewStickyConnPool(pool Pooler) *StickyConnPool {
+	p, ok := pool.(*StickyConnPool)
+	if !ok {
+		p = &StickyConnPool{
+			pool: pool,
+			ch:   make(chan *Conn, 1),
+		}
+	}
+	atomic.AddInt32(&p.shared, 1)
+	return p
+}
+
+func (p *StickyConnPool) NewConn(ctx context.Context) (*Conn, error) {
+	return p.pool.NewConn(ctx)
+}
+
+func (p *StickyConnPool) CloseConn(cn *Conn) error {
+	return p.pool.CloseConn(cn)
+}
+
+func (p *StickyConnPool) Get(ctx context.Context) (*Conn, error) {
+	// In worst case this races with Close which is not a very common operation.
+	for i := 0; i < 1000; i++ {
+		switch atomic.LoadUint32(&p.state) {
+		case stateDefault:
+			cn, err := p.pool.Get(ctx)
+			if err != nil {
+				return nil, err
+			}
+			if atomic.CompareAndSwapUint32(&p.state, stateDefault, stateInited) {
+				return cn, nil
+			}
+			p.pool.Remove(ctx, cn, ErrClosed)
+		case stateInited:
+			if err := p.badConnError(); err != nil {
+				return nil, err
+			}
+			cn, ok := <-p.ch
+			if !ok {
+				return nil, ErrClosed
+			}
+			return cn, nil
+		case stateClosed:
+			return nil, ErrClosed
+		default:
+			panic("not reached")
+		}
+	}
+	return nil, fmt.Errorf("redis: StickyConnPool.Get: infinite loop")
+}
+
+func (p *StickyConnPool) Put(ctx context.Context, cn *Conn) {
+	defer func() {
+		if recover() != nil {
+			p.freeConn(ctx, cn)
+		}
+	}()
+	p.ch <- cn
+}
+
+func (p *StickyConnPool) freeConn(ctx context.Context, cn *Conn) {
+	if err := p.badConnError(); err != nil {
+		p.pool.Remove(ctx, cn, err)
+	} else {
+		p.pool.Put(ctx, cn)
+	}
+}
+
+func (p *StickyConnPool) Remove(ctx context.Context, cn *Conn, reason error) {
+	defer func() {
+		if recover() != nil {
+			p.pool.Remove(ctx, cn, ErrClosed)
+		}
+	}()
+	p._badConnError.Store(BadConnError{wrapped: reason})
+	p.ch <- cn
+}
+
+func (p *StickyConnPool) Close() error {
+	if shared := atomic.AddInt32(&p.shared, -1); shared > 0 {
+		return nil
+	}
+
+	for i := 0; i < 1000; i++ {
+		state := atomic.LoadUint32(&p.state)
+		if state == stateClosed {
+			return ErrClosed
+		}
+		if atomic.CompareAndSwapUint32(&p.state, state, stateClosed) {
+			close(p.ch)
+			cn, ok := <-p.ch
+			if ok {
+				p.freeConn(context.TODO(), cn)
+			}
+			return nil
+		}
+	}
+
+	return errors.New("redis: StickyConnPool.Close: infinite loop")
+}
+
+func (p *StickyConnPool) Reset(ctx context.Context) error {
+	if p.badConnError() == nil {
+		return nil
+	}
+
+	select {
+	case cn, ok := <-p.ch:
+		if !ok {
+			return ErrClosed
+		}
+		p.pool.Remove(ctx, cn, ErrClosed)
+		p._badConnError.Store(BadConnError{wrapped: nil})
+	default:
+		return errors.New("redis: StickyConnPool does not have a Conn")
+	}
+
+	if !atomic.CompareAndSwapUint32(&p.state, stateInited, stateDefault) {
+		state := atomic.LoadUint32(&p.state)
+		return fmt.Errorf("redis: invalid StickyConnPool state: %d", state)
+	}
+
+	return nil
+}
+
+func (p *StickyConnPool) badConnError() error {
+	if v := p._badConnError.Load(); v != nil {
+		err := v.(BadConnError)
+		if err.wrapped != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (p *StickyConnPool) Len() int {
+	switch atomic.LoadUint32(&p.state) {
+	case stateDefault:
+		return 0
+	case stateInited:
+		return 1
+	case stateClosed:
+		return 0
+	default:
+		panic("not reached")
+	}
+}
+
+func (p *StickyConnPool) IdleLen() int {
+	return len(p.ch)
+}
+
+func (p *StickyConnPool) Stats() *Stats {
+	return &Stats{}
+}