Backport #14368 to v3.5

client/v3/client.go

@@ -502,15 +502,15 @@ func (c *Client) checkVersion() (err error) {
 					return
 				}
 			}
-			if maj < 3 || (maj == 3 && min < 2) {
+			if maj < 3 || (maj == 3 && min < 4) {
 				rerr = ErrOldCluster
 			}
 			errc <- rerr
 		}(ep)
 	}
 	// wait for success
 	for range eps {
-		if err = <-errc; err == nil {
+		if err = <-errc; err != nil {
 			break
 		}
 	}

client/v3/client_test.go

@@ -17,7 +17,9 @@ package clientv3
 import (
 	"context"
 	"fmt"
+	"io"
 	"net"
+	"sync"
 	"testing"
 	"time"
 
@@ -294,3 +296,99 @@ func (mc *mockCluster) MemberUpdate(ctx context.Context, id uint64, peerAddrs []
 func (mc *mockCluster) MemberPromote(ctx context.Context, id uint64) (*MemberPromoteResponse, error) {
 	return nil, nil
 }
+
+func TestClientRejectOldCluster(t *testing.T) {
+	testutil.RegisterLeakDetection(t)
+	var tests = []struct {
+		name          string
+		endpoints     []string
+		versions      []string
+		expectedError error
+	}{
+		{
+			name:          "all new versions with the same value",
+			endpoints:     []string{"192.168.3.41:22379", "192.168.3.41:22479", "192.168.3.41:22579"},
+			versions:      []string{"3.5.4", "3.5.4", "3.5.4"},
+			expectedError: nil,
+		},
+		{
+			name:          "all new versions with different values",
+			endpoints:     []string{"192.168.3.41:22379", "192.168.3.41:22479", "192.168.3.41:22579"},
+			versions:      []string{"3.5.4", "3.5.4", "3.4.0"},
+			expectedError: nil,
+		},
+		{
+			name:          "all old versions with different values",
+			endpoints:     []string{"192.168.3.41:22379", "192.168.3.41:22479", "192.168.3.41:22579"},
+			versions:      []string{"3.3.0", "3.3.0", "3.4.0"},
+			expectedError: ErrOldCluster,
+		},
+		{
+			name:          "all old versions with the same value",
+			endpoints:     []string{"192.168.3.41:22379", "192.168.3.41:22479", "192.168.3.41:22579"},
+			versions:      []string{"3.3.0", "3.3.0", "3.3.0"},
+			expectedError: ErrOldCluster,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if len(tt.endpoints) != len(tt.versions) || len(tt.endpoints) == 0 {
+				t.Errorf("Unexpected endpoints and versions length, len(endpoints):%d, len(versions):%d", len(tt.endpoints), len(tt.versions))
+				return
+			}
+			endpointToVersion := make(map[string]string)
+			for j := range tt.endpoints {
+				endpointToVersion[tt.endpoints[j]] = tt.versions[j]
+			}
+			c := &Client{
+				ctx: context.Background(),
+				cfg: Config{
+					Endpoints: tt.endpoints,
+				},
+				mu: new(sync.RWMutex),
+				Maintenance: &mockMaintenance{
+					Version: endpointToVersion,
+				},
+			}
+
+			if err := c.checkVersion(); err != tt.expectedError {
+				t.Errorf("heckVersion err:%v", err)
+			}
+		})
+
+	}
+
+}
+
+type mockMaintenance struct {
+	Version map[string]string
+}
+
+func (mm mockMaintenance) Status(ctx context.Context, endpoint string) (*StatusResponse, error) {
+	return &StatusResponse{Version: mm.Version[endpoint]}, nil
+}
+
+func (mm mockMaintenance) AlarmList(ctx context.Context) (*AlarmResponse, error) {
+	return nil, nil
+}
+
+func (mm mockMaintenance) AlarmDisarm(ctx context.Context, m *AlarmMember) (*AlarmResponse, error) {
+	return nil, nil
+}
+
+func (mm mockMaintenance) Defragment(ctx context.Context, endpoint string) (*DefragmentResponse, error) {
+	return nil, nil
+}
+
+func (mm mockMaintenance) HashKV(ctx context.Context, endpoint string, rev int64) (*HashKVResponse, error) {
+	return nil, nil
+}
+
+func (mm mockMaintenance) Snapshot(ctx context.Context) (io.ReadCloser, error) {
+	return nil, nil
+}
+
+func (mm mockMaintenance) MoveLeader(ctx context.Context, transfereeID uint64) (*MoveLeaderResponse, error) {
+	return nil, nil
+}