Fix Data Race in hooksMixin When Using MinIdleConns and AddHook

redis.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"sync"
 	"sync/atomic"
 	"time"
 
@@ -40,12 +41,15 @@ type (
 )
 
 type hooksMixin struct {
+	hooksMu *sync.Mutex
+
 	slice   []Hook
 	initial hooks
 	current hooks
 }
 
 func (hs *hooksMixin) initHooks(hooks hooks) {
+	hs.hooksMu = new(sync.Mutex)
 	hs.initial = hooks
 	hs.chain()
 }
@@ -116,6 +120,9 @@ func (hs *hooksMixin) AddHook(hook Hook) {
 func (hs *hooksMixin) chain() {
 	hs.initial.setDefaults()
 
+	hs.hooksMu.Lock()
+	defer hs.hooksMu.Unlock()
+
 	hs.current.dial = hs.initial.dial
 	hs.current.process = hs.initial.process
 	hs.current.pipeline = hs.initial.pipeline
@@ -138,9 +145,13 @@ func (hs *hooksMixin) chain() {
 }
 
 func (hs *hooksMixin) clone() hooksMixin {
+	hs.hooksMu.Lock()
+	defer hs.hooksMu.Unlock()
+
 	clone := *hs
 	l := len(clone.slice)
 	clone.slice = clone.slice[:l:l]
+	clone.hooksMu = new(sync.Mutex)
 	return clone
 }
 
@@ -165,6 +176,8 @@ func (hs *hooksMixin) withProcessPipelineHook(
 }
 
 func (hs *hooksMixin) dialHook(ctx context.Context, network, addr string) (net.Conn, error) {
+	hs.hooksMu.Lock()
+	defer hs.hooksMu.Unlock()
 	return hs.current.dial(ctx, network, addr)
 }
 

redis_test.go

@@ -579,3 +579,53 @@ var _ = Describe("Hook", func() {
 		Expect(cmd.Val()).To(Equal("Script and hook"))
 	})
 })
+
+var _ = Describe("Hook with MinIdleConns", func() {
+	var client *redis.Client
+
+	BeforeEach(func() {
+		options := redisOptions()
+		options.MinIdleConns = 1
+		client = redis.NewClient(options)
+		Expect(client.FlushDB(ctx).Err()).NotTo(HaveOccurred())
+	})
+
+	AfterEach(func() {
+		err := client.Close()
+		Expect(err).NotTo(HaveOccurred())
+	})
+
+	It("fifo", func() {
+		var res []string
+		client.AddHook(&hook{
+			processHook: func(hook redis.ProcessHook) redis.ProcessHook {
+				return func(ctx context.Context, cmd redis.Cmder) error {
+					res = append(res, "hook-1-process-start")
+					err := hook(ctx, cmd)
+					res = append(res, "hook-1-process-end")
+					return err
+				}
+			},
+		})
+		client.AddHook(&hook{
+			processHook: func(hook redis.ProcessHook) redis.ProcessHook {
+				return func(ctx context.Context, cmd redis.Cmder) error {
+					res = append(res, "hook-2-process-start")
+					err := hook(ctx, cmd)
+					res = append(res, "hook-2-process-end")
+					return err
+				}
+			},
+		})
+
+		err := client.Ping(ctx).Err()
+		Expect(err).NotTo(HaveOccurred())
+
+		Expect(res).To(Equal([]string{
+			"hook-1-process-start",
+			"hook-2-process-start",
+			"hook-2-process-end",
+			"hook-1-process-end",
+		}))
+	})
+})