Fix ReceiveMessage to work without any subscriptions.

Makefile

@@ -15,4 +15,5 @@ testdata/redis:
 	wget -qO- https://github.com/antirez/redis/archive/unstable.tar.gz | tar xvz --strip-components=1 -C $@
 
 testdata/redis/src/redis-server: testdata/redis
+	sed -i 's/libjemalloc.a/libjemalloc.a -lrt/g' $</src/Makefile
 	cd $< && make all

command.go

@@ -58,7 +58,7 @@ func writeCmd(cn *pool.Conn, cmds ...Cmder) error {
 		}
 	}
 
-	_, err := cn.NetConn.Write(cn.Wb.Bytes())
+	_, err := cn.Write(cn.Wb.Bytes())
 	return err
 }
 

internal/pool/conn.go

@@ -2,56 +2,78 @@ package pool
 
 import (
 	"net"
+	"sync/atomic"
 	"time"
 
 	"gopkg.in/redis.v5/internal/proto"
 )
 
-const defaultBufSize = 4096
-
 var noDeadline = time.Time{}
 
 type Conn struct {
-	NetConn net.Conn
+	netConn net.Conn
+
 	Rd *proto.Reader
 	Wb *proto.WriteBuffer
 
 	Inited bool
-	UsedAt time.Time
+	usedAt atomic.Value
 }
 
 func NewConn(netConn net.Conn) *Conn {
+	buf := make([]byte, 4096)
 	cn := &Conn{
-		NetConn: netConn,
+		netConn: netConn,
-		Wb:      proto.NewWriteBuffer(),
+		Wb:      proto.NewWriteBuffer(buf),
-
-		UsedAt: time.Now(),
 	}
-	cn.Rd = proto.NewReader(cn.NetConn)
+	cn.Rd = proto.NewReader(cn.netConn, buf)
+	cn.SetUsedAt(time.Now())
 	return cn
 }
 
+func (cn *Conn) UsedAt() time.Time {
+	return cn.usedAt.Load().(time.Time)
+}
+
+func (cn *Conn) SetUsedAt(tm time.Time) {
+	cn.usedAt.Store(tm)
+}
+
+func (cn *Conn) SetNetConn(netConn net.Conn) {
+	cn.netConn = netConn
+	cn.Rd.Reset(netConn)
+}
+
 func (cn *Conn) IsStale(timeout time.Duration) bool {
-	return timeout > 0 && time.Since(cn.UsedAt) > timeout
+	return timeout > 0 && time.Since(cn.UsedAt()) > timeout
 }
 
 func (cn *Conn) SetReadTimeout(timeout time.Duration) error {
-	cn.UsedAt = time.Now()
+	now := time.Now()
+	cn.SetUsedAt(now)
 	if timeout > 0 {
-		return cn.NetConn.SetReadDeadline(cn.UsedAt.Add(timeout))
+		return cn.netConn.SetReadDeadline(now.Add(timeout))
 	}
-	return cn.NetConn.SetReadDeadline(noDeadline)
+	return cn.netConn.SetReadDeadline(noDeadline)
-
 }
 
 func (cn *Conn) SetWriteTimeout(timeout time.Duration) error {
-	cn.UsedAt = time.Now()
+	now := time.Now()
+	cn.SetUsedAt(now)
 	if timeout > 0 {
-		return cn.NetConn.SetWriteDeadline(cn.UsedAt.Add(timeout))
+		return cn.netConn.SetWriteDeadline(now.Add(timeout))
 	}
-	return cn.NetConn.SetWriteDeadline(noDeadline)
+	return cn.netConn.SetWriteDeadline(noDeadline)
+}
+
+func (cn *Conn) Write(b []byte) (int, error) {
+	return cn.netConn.Write(b)
+}
+
+func (cn *Conn) RemoteAddr() net.Addr {
+	return cn.netConn.RemoteAddr()
 }
 
 func (cn *Conn) Close() error {
-	return cn.NetConn.Close()
+	return cn.netConn.Close()
 }

internal/pool/pool.go

@@ -41,7 +41,6 @@ type Pooler interface {
 	FreeLen() int
 	Stats() *Stats
 	Close() error
-	Closed() bool
 }
 
 type dialer func() (net.Conn, error)
@@ -132,7 +131,7 @@ func (p *ConnPool) popFree() *Conn {
 
 // Get returns existed connection from the pool or creates a new one.
 func (p *ConnPool) Get() (*Conn, bool, error) {
-	if p.Closed() {
+	if p.closed() {
 		return nil, false, ErrClosed
 	}
 
@@ -241,7 +240,7 @@ func (p *ConnPool) Stats() *Stats {
 	}
 }
 
-func (p *ConnPool) Closed() bool {
+func (p *ConnPool) closed() bool {
 	return atomic.LoadInt32(&p._closed) == 1
 }
 
@@ -318,7 +317,7 @@ func (p *ConnPool) reaper(frequency time.Duration) {
 	defer ticker.Stop()
 
 	for _ = range ticker.C {
-		if p.Closed() {
+		if p.closed() {
 			break
 		}
 		n, err := p.ReapStaleConns()

internal/pool/pool_single.go

@@ -12,10 +12,6 @@ func NewSingleConnPool(cn *Conn) *SingleConnPool {
 	}
 }
 
-func (p *SingleConnPool) First() *Conn {
-	return p.cn
-}
-
 func (p *SingleConnPool) Get() (*Conn, bool, error) {
 	return p.cn, false, nil
 }
@@ -49,7 +45,3 @@ func (p *SingleConnPool) Stats() *Stats {
 func (p *SingleConnPool) Close() error {
 	return nil
 }
-
-func (p *SingleConnPool) Closed() bool {
-	return false
-}

internal/pool/pool_sticky.go

@@ -23,13 +23,6 @@ func NewStickyConnPool(pool *ConnPool, reusable bool) *StickyConnPool {
 	}
 }
 
-func (p *StickyConnPool) First() *Conn {
-	p.mu.Lock()
-	cn := p.cn
-	p.mu.Unlock()
-	return cn
-}
-
 func (p *StickyConnPool) Get() (*Conn, bool, error) {
 	p.mu.Lock()
 	defer p.mu.Unlock()
@@ -62,9 +55,6 @@ func (p *StickyConnPool) Put(cn *Conn) error {
 	if p.closed {
 		return ErrClosed
 	}
-	if p.cn != cn {
-		panic("p.cn != cn")
-	}
 	return nil
 }
 
@@ -81,12 +71,6 @@ func (p *StickyConnPool) Remove(cn *Conn, reason error) error {
 	if p.closed {
 		return nil
 	}
-	if p.cn == nil {
-		panic("p.cn == nil")
-	}
-	if cn != nil && p.cn != cn {
-		panic("p.cn != cn")
-	}
 	return p.removeUpstream(reason)
 }
 
@@ -133,10 +117,3 @@ func (p *StickyConnPool) Close() error {
 	}
 	return err
 }
-
-func (p *StickyConnPool) Closed() bool {
-	p.mu.Lock()
-	closed := p.closed
-	p.mu.Unlock()
-	return closed
-}

internal/pool/pool_test.go

@@ -100,7 +100,7 @@ var _ = Describe("conns reaper", func() {
 		for i := 0; i < 3; i++ {
 			cn, _, err := connPool.Get()
 			Expect(err).NotTo(HaveOccurred())
-			cn.UsedAt = time.Now().Add(-2 * idleTimeout)
+			cn.SetUsedAt(time.Now().Add(-2 * idleTimeout))
 			conns = append(conns, cn)
 			idleConns = append(idleConns, cn)
 		}

internal/proto/reader.go

@@ -26,13 +26,17 @@ type Reader struct {
 	buf []byte
 }
 
-func NewReader(rd io.Reader) *Reader {
+func NewReader(rd io.Reader, buf []byte) *Reader {
 	return &Reader{
 		src: bufio.NewReader(rd),
-		buf: make([]byte, 0, bufferSize),
+		buf: buf,
 	}
 }
 
+func (r *Reader) Reset(rd io.Reader) {
+	r.src.Reset(rd)
+}
+
 func (p *Reader) PeekBuffered() []byte {
 	if n := p.src.Buffered(); n != 0 {
 		b, _ := p.src.Peek(n)
@@ -42,7 +46,12 @@ func (p *Reader) PeekBuffered() []byte {
 }
 
 func (p *Reader) ReadN(n int) ([]byte, error) {
-	return readN(p.src, p.buf, n)
+	b, err := readN(p.src, p.buf, n)
+	if err != nil {
+		return nil, err
+	}
+	p.buf = b
+	return b, nil
 }
 
 func (p *Reader) ReadLine() ([]byte, error) {
@@ -72,11 +81,11 @@ func (p *Reader) ReadReply(m MultiBulkParse) (interface{}, error) {
 	case ErrorReply:
 		return nil, ParseErrorReply(line)
 	case StatusReply:
-		return parseStatusValue(line)
+		return parseStatusValue(line), nil
 	case IntReply:
 		return parseInt(line[1:], 10, 64)
 	case StringReply:
-		return p.readBytesValue(line)
+		return p.readTmpBytesValue(line)
 	case ArrayReply:
 		n, err := parseArrayLen(line)
 		if err != nil {
@@ -111,9 +120,9 @@ func (p *Reader) ReadTmpBytesReply() ([]byte, error) {
 	case ErrorReply:
 		return nil, ParseErrorReply(line)
 	case StringReply:
-		return p.readBytesValue(line)
+		return p.readTmpBytesValue(line)
 	case StatusReply:
-		return parseStatusValue(line)
+		return parseStatusValue(line), nil
 	default:
 		return nil, fmt.Errorf("redis: can't parse string reply: %.100q", line)
 	}
@@ -210,7 +219,7 @@ func (p *Reader) ReadScanReply() ([]string, uint64, error) {
 	return keys, cursor, err
 }
 
-func (p *Reader) readBytesValue(line []byte) ([]byte, error) {
+func (p *Reader) readTmpBytesValue(line []byte) ([]byte, error) {
 	if isNilReply(line) {
 		return nil, internal.Nil
 	}
@@ -297,8 +306,8 @@ func ParseErrorReply(line []byte) error {
 	return internal.RedisError(string(line[1:]))
 }
 
-func parseStatusValue(line []byte) ([]byte, error) {
+func parseStatusValue(line []byte) []byte {
-	return line[1:], nil
+	return line[1:]
 }
 
 func parseArrayLen(line []byte) (int64, error) {

internal/proto/reader_test.go

@@ -5,27 +5,27 @@ import (
 	"strings"
 	"testing"
 
+	"gopkg.in/redis.v5/internal/proto"
+
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
-
-	"gopkg.in/redis.v5/internal/proto"
 )
 
 var _ = Describe("Reader", func() {
 
 	It("should read n bytes", func() {
-		data, err := proto.NewReader(strings.NewReader("ABCDEFGHIJKLMNO")).ReadN(10)
+		data, err := proto.NewReader(strings.NewReader("ABCDEFGHIJKLMNO"), nil).ReadN(10)
 		Expect(err).NotTo(HaveOccurred())
 		Expect(len(data)).To(Equal(10))
 		Expect(string(data)).To(Equal("ABCDEFGHIJ"))
 
-		data, err = proto.NewReader(strings.NewReader(strings.Repeat("x", 8192))).ReadN(6000)
+		data, err = proto.NewReader(strings.NewReader(strings.Repeat("x", 8192)), nil).ReadN(6000)
 		Expect(err).NotTo(HaveOccurred())
 		Expect(len(data)).To(Equal(6000))
 	})
 
 	It("should read lines", func() {
-		p := proto.NewReader(strings.NewReader("$5\r\nhello\r\n"))
+		p := proto.NewReader(strings.NewReader("$5\r\nhello\r\n"), nil)
 
 		data, err := p.ReadLine()
 		Expect(err).NotTo(HaveOccurred())
@@ -59,11 +59,11 @@ func BenchmarkReader_ParseReply_Slice(b *testing.B) {
 }
 
 func benchmarkParseReply(b *testing.B, reply string, m proto.MultiBulkParse, wanterr bool) {
-	buf := &bytes.Buffer{}
+	buf := new(bytes.Buffer)
 	for i := 0; i < b.N; i++ {
 		buf.WriteString(reply)
 	}
-	p := proto.NewReader(buf)
+	p := proto.NewReader(buf, nil)
 	b.ResetTimer()
 
 	for i := 0; i < b.N; i++ {

internal/proto/write_buffer.go

@@ -8,11 +8,13 @@ import (
 
 const bufferSize = 4096
 
-type WriteBuffer struct{ b []byte }
+type WriteBuffer struct {
+	b []byte
+}
 
-func NewWriteBuffer() *WriteBuffer {
+func NewWriteBuffer(b []byte) *WriteBuffer {
 	return &WriteBuffer{
-		b: make([]byte, 0, bufferSize),
+		b: b,
 	}
 }
 

internal/proto/write_buffer_test.go

@@ -4,17 +4,17 @@ import (
 	"testing"
 	"time"
 
+	"gopkg.in/redis.v5/internal/proto"
+
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
-
-	"gopkg.in/redis.v5/internal/proto"
 )
 
 var _ = Describe("WriteBuffer", func() {
 	var buf *proto.WriteBuffer
 
 	BeforeEach(func() {
-		buf = proto.NewWriteBuffer()
+		buf = proto.NewWriteBuffer(nil)
 	})
 
 	It("should reset", func() {
@@ -53,7 +53,7 @@ var _ = Describe("WriteBuffer", func() {
 })
 
 func BenchmarkWriteBuffer_Append(b *testing.B) {
-	buf := proto.NewWriteBuffer()
+	buf := proto.NewWriteBuffer(nil)
 	args := []interface{}{"hello", "world", "foo", "bar"}
 
 	for i := 0; i < b.N; i++ {

pool_test.go

@@ -93,7 +93,7 @@ var _ = Describe("pool", func() {
 	It("removes broken connections", func() {
 		cn, _, err := client.Pool().Get()
 		Expect(err).NotTo(HaveOccurred())
-		cn.NetConn = &badConn{}
+		cn.SetNetConn(&badConn{})
 		Expect(client.Pool().Put(cn)).NotTo(HaveOccurred())
 
 		err = client.Ping().Err()

pubsub.go

@@ -3,6 +3,7 @@ package redis
 import (
 	"fmt"
 	"net"
+	"sync"
 	"time"
 
 	"gopkg.in/redis.v5/internal"
@@ -14,7 +15,9 @@ import (
 // multiple goroutines.
 type PubSub struct {
 	base baseClient
+	cmd  *Cmd
 
+	mu       sync.Mutex
 	channels []string
 	patterns []string
 }
@@ -150,7 +153,13 @@ func (p *Pong) String() string {
 	return "Pong"
 }
 
-func (c *PubSub) newMessage(reply []interface{}) (interface{}, error) {
+func (c *PubSub) newMessage(reply interface{}) (interface{}, error) {
+	switch reply := reply.(type) {
+	case string:
+		return &Pong{
+			Payload: reply,
+		}, nil
+	case []interface{}:
 		switch kind := reply[0].(string); kind {
 		case "subscribe", "unsubscribe", "psubscribe", "punsubscribe":
 			return &Subscription{
@@ -174,7 +183,10 @@ func (c *PubSub) newMessage(reply []interface{}) (interface{}, error) {
 				Payload: reply[1].(string),
 			}, nil
 		default:
-		return nil, fmt.Errorf("redis: unsupported pubsub notification: %q", kind)
+			return nil, fmt.Errorf("redis: unsupported pubsub message: %q", kind)
+		}
+	default:
+		return nil, fmt.Errorf("redis: unsupported pubsub message: %#v", reply)
 	}
 }
 
@@ -182,7 +194,9 @@ func (c *PubSub) newMessage(reply []interface{}) (interface{}, error) {
 // is not received in time. This is low-level API and most clients
 // should use ReceiveMessage.
 func (c *PubSub) ReceiveTimeout(timeout time.Duration) (interface{}, error) {
-	cmd := NewSliceCmd()
+	if c.cmd == nil {
+		c.cmd = NewCmd()
+	}
 
 	cn, _, err := c.conn()
 	if err != nil {
@@ -190,13 +204,13 @@ func (c *PubSub) ReceiveTimeout(timeout time.Duration) (interface{}, error) {
 	}
 
 	cn.SetReadTimeout(timeout)
-	err = cmd.readReply(cn)
+	err = c.cmd.readReply(cn)
 	c.putConn(cn, err)
 	if err != nil {
 		return nil, err
 	}
 
-	return c.newMessage(cmd.Val())
+	return c.newMessage(c.cmd.Val())
 }
 
 // Receive returns a message as a Subscription, Message, Pong or error.
@@ -225,14 +239,14 @@ func (c *PubSub) receiveMessage(timeout time.Duration) (*Message, error) {
 			errNum++
 			if errNum < 3 {
 				if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
-					err := c.Ping("")
+					err := c.Ping("hello")
 					if err != nil {
 						internal.Logf("PubSub.Ping failed: %s", err)
 					}
 				}
 			} else {
-				// 3 consequent errors - connection is bad
+				// 3 consequent errors - connection is broken or
-				// and/or Redis Server is down.
+				// Redis Server is down.
 				// Sleep to not exceed max number of open connections.
 				time.Sleep(time.Second)
 			}
@@ -256,9 +270,6 @@ func (c *PubSub) receiveMessage(timeout time.Duration) (*Message, error) {
 }
 
 func (c *PubSub) resubscribe() {
-	if c.base.closed() {
-		return
-	}
 	if len(c.channels) > 0 {
 		if err := c.Subscribe(c.channels...); err != nil {
 			internal.Logf("Subscribe failed: %s", err)

pubsub_test.go

@@ -288,12 +288,13 @@ var _ = Describe("PubSub", func() {
 	})
 
 	expectReceiveMessageOnError := func(pubsub *redis.PubSub) {
-		cn1, _, err := pubsub.Pool().Get()
+		cn, _, err := pubsub.Pool().Get()
 		Expect(err).NotTo(HaveOccurred())
-		cn1.NetConn = &badConn{
+		cn.SetNetConn(&badConn{
 			readErr:  io.EOF,
 			writeErr: io.EOF,
-		}
+		})
+		pubsub.Pool().Put(cn)
 
 		done := make(chan bool, 1)
 		go func() {
@@ -315,7 +316,7 @@ var _ = Describe("PubSub", func() {
 		Eventually(done).Should(Receive())
 
 		stats := client.PoolStats()
-		Expect(stats.Requests).To(Equal(uint32(3)))
+		Expect(stats.Requests).To(Equal(uint32(4)))
 		Expect(stats.Hits).To(Equal(uint32(1)))
 	}
 
@@ -362,4 +363,27 @@ var _ = Describe("PubSub", func() {
 		wg.Wait()
 	})
 
+	It("should ReceiveMessage without a subscription", func() {
+		timeout := 100 * time.Millisecond
+
+		pubsub, err := client.Subscribe()
+		Expect(err).NotTo(HaveOccurred())
+		defer pubsub.Close()
+
+		go func() {
+			defer GinkgoRecover()
+
+			time.Sleep(2 * timeout)
+			err = pubsub.Subscribe("mychannel")
+			Expect(err).NotTo(HaveOccurred())
+
+			err := client.Publish("mychannel", "hello").Err()
+			Expect(err).NotTo(HaveOccurred())
+		}()
+
+		msg, err := pubsub.ReceiveMessageTimeout(timeout)
+		Expect(err).NotTo(HaveOccurred())
+		Expect(msg.Channel).To(Equal("mychannel"))
+		Expect(msg.Payload).To(Equal("hello"))
+	})
 })

redis.go

@@ -126,10 +126,6 @@ func (c *baseClient) cmdTimeout(cmd Cmder) time.Duration {
 	}
 }
 
-func (c *baseClient) closed() bool {
-	return c.connPool.Closed()
-}
-
 // Close closes the client, releasing any open resources.
 //
 // It is rare to Close a Client, as the Client is meant to be

redis_test.go

@@ -148,7 +148,7 @@ var _ = Describe("Client", func() {
 		cn, _, err := client.Pool().Get()
 		Expect(err).NotTo(HaveOccurred())
 
-		cn.NetConn = &badConn{}
+		cn.SetNetConn(&badConn{})
 		err = client.Pool().Put(cn)
 		Expect(err).NotTo(HaveOccurred())
 
@@ -160,11 +160,11 @@ var _ = Describe("Client", func() {
 		cn, _, err := client.Pool().Get()
 		Expect(err).NotTo(HaveOccurred())
 		Expect(cn.UsedAt).NotTo(BeZero())
-		createdAt := cn.UsedAt
+		createdAt := cn.UsedAt()
 
 		err = client.Pool().Put(cn)
 		Expect(err).NotTo(HaveOccurred())
-		Expect(cn.UsedAt.Equal(createdAt)).To(BeTrue())
+		Expect(cn.UsedAt().Equal(createdAt)).To(BeTrue())
 
 		err = client.Ping().Err()
 		Expect(err).NotTo(HaveOccurred())
@@ -172,7 +172,7 @@ var _ = Describe("Client", func() {
 		cn, _, err = client.Pool().Get()
 		Expect(err).NotTo(HaveOccurred())
 		Expect(cn).NotTo(BeNil())
-		Expect(cn.UsedAt.After(createdAt)).To(BeTrue())
+		Expect(cn.UsedAt().After(createdAt)).To(BeTrue())
 	})
 
 	It("should process command with special chars", func() {

sentinel.go

@@ -258,7 +258,7 @@ func (d *sentinelFailover) discoverSentinels(sentinel *sentinelClient) {
 // closeOldConns closes connections to the old master after failover switch.
 func (d *sentinelFailover) closeOldConns(newMaster string) {
 	// Good connections that should be put back to the pool. They
-	// can't be put immediately, because pool.First will return them
+	// can't be put immediately, because pool.PopFree will return them
 	// again on next iteration.
 	cnsToPut := make([]*pool.Conn, 0)
 
@@ -267,10 +267,10 @@ func (d *sentinelFailover) closeOldConns(newMaster string) {
 		if cn == nil {
 			break
 		}
-		if cn.NetConn.RemoteAddr().String() != newMaster {
+		if cn.RemoteAddr().String() != newMaster {
 			err := fmt.Errorf(
 				"sentinel: closing connection to the old master %s",
-				cn.NetConn.RemoteAddr(),
+				cn.RemoteAddr(),
 			)
 			internal.Logf(err.Error())
 			d.pool.Remove(cn, err)
@@ -289,8 +289,10 @@ func (d *sentinelFailover) listen(sentinel *sentinelClient) {
 	for {
 		if pubsub == nil {
 			pubsub = sentinel.PubSub()
+
 			if err := pubsub.Subscribe("+switch-master"); err != nil {
 				internal.Logf("sentinel: Subscribe failed: %s", err)
+				pubsub.Close()
 				d.resetSentinel()
 				return
 			}

tx_test.go

@@ -127,7 +127,7 @@ var _ = Describe("Tx", func() {
 		cn, _, err := client.Pool().Get()
 		Expect(err).NotTo(HaveOccurred())
 
-		cn.NetConn = &badConn{}
+		cn.SetNetConn(&badConn{})
 		err = client.Pool().Put(cn)
 		Expect(err).NotTo(HaveOccurred())