etcd: modify declaring empty slices

client/pkg/srv/srv.go

@@ -45,7 +45,7 @@ func GetCluster(serviceScheme, service, name, dns string, apurls types.URLs) ([]
 		tcp2ap[tcpAddr.String()] = url
 	}
 
-	stringParts := []string{}
+	var stringParts []string
 	updateNodeMap := func(service, scheme string) error {
 		_, addrs, err := lookupSRV(service, "tcp", dns)
 		if err != nil {

client/pkg/srv/srv_test.go

@@ -52,7 +52,7 @@ func TestSRVGetCluster(t *testing.T) {
 		{Target: "2.example.com.", Port: 2480},
 		{Target: "3.example.com.", Port: 2480},
 	}
-	srvNone := []*net.SRV{}
+	var srvNone []*net.SRV
 
 	tests := []struct {
 		service    string

client/pkg/transport/listener_tls.go

@@ -222,7 +222,8 @@ func checkCertSAN(ctx context.Context, cert *x509.Certificate, remoteAddr string
 
 func isHostInDNS(ctx context.Context, host string, dnsNames []string) (ok bool, err error) {
 	// reverse lookup
-	wildcards, names := []string{}, []string{}
+	var names []string
+	var wildcards []string
 	for _, dns := range dnsNames {
 		if strings.HasPrefix(dns, "*.") {
 			wildcards = append(wildcards, dns[1:])

client/pkg/types/set.go

@@ -90,7 +90,7 @@ func (us *unsafeSet) Length() int {
 
 // Values returns the values of the Set in an unspecified order.
 func (us *unsafeSet) Values() (values []string) {
-	values = make([]string, 0)
+	values = make([]string, 0, len(us.d))
 	for val := range us.d {
 		values = append(values, val)
 	}

client/pkg/types/set_test.go

@@ -39,10 +39,9 @@ func equal(a, b []string) bool {
 
 func driveSetTests(t *testing.T, s Set) {
 	// Verify operations on an empty set
-	eValues := []string{}
 	values := s.Values()
-	if !reflect.DeepEqual(values, eValues) {
-		t.Fatalf("Expect values=%v got %v", eValues, values)
+	if len(values) != 0 {
+		t.Fatalf("Expect values=%v got %v", []string{}, values)
 	}
 	if l := s.Length(); l != 0 {
 		t.Fatalf("Expected length=0, got %d", l)
@@ -58,7 +57,7 @@ func driveSetTests(t *testing.T, s Set) {
 	s.Add("bar")
 	s.Add("baz")
 
-	eValues = []string{"foo", "bar", "baz"}
+	eValues := []string{"foo", "bar", "baz"}
 	values = s.Values()
 	if !equal(values, eValues) {
 		t.Fatalf("Expect values=%v got %v", eValues, values)

etcdctl/ctlv3/command/del_command.go

@@ -20,7 +20,7 @@ import (
 	"time"
 
 	"github.com/spf13/cobra"
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/pkg/v3/cobrautl"
 )
 
@@ -67,7 +67,7 @@ func getDelOp(args []string) (string, []clientv3.OpOption) {
 		cobrautl.ExitWithError(cobrautl.ExitBadArgs, fmt.Errorf("`--prefix` and `--from-key` cannot be set at the same time, choose one"))
 	}
 
-	opts := []clientv3.OpOption{}
+	var opts []clientv3.OpOption
 	key := args[0]
 	if len(args) > 1 {
 		if delPrefix || delFromKey {

etcdctl/ctlv3/command/ep_command.go

@@ -23,7 +23,7 @@ import (
 	"go.etcd.io/etcd/api/v3/etcdserverpb"
 	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
 	"go.etcd.io/etcd/client/pkg/v3/logutil"
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/pkg/v3/cobrautl"
 	"go.etcd.io/etcd/pkg/v3/flags"
 
@@ -101,7 +101,7 @@ func epHealthCommandFunc(cmd *cobra.Command, args []string) {
 	ka := keepAliveTimeFromCmd(cmd)
 	kat := keepAliveTimeoutFromCmd(cmd)
 	auth := authCfgFromCmd(cmd)
-	cfgs := []*clientv3.Config{}
+	var cfgs []*clientv3.Config
 	for _, ep := range endpointsFromCluster(cmd) {
 		cfg, err := clientv3.NewClientConfig(&clientv3.ConfigSpec{
 			Endpoints:        []string{ep},
@@ -172,7 +172,7 @@ func epHealthCommandFunc(cmd *cobra.Command, args []string) {
 	close(hch)
 
 	errs := false
-	healthList := []epHealth{}
+	var healthList []epHealth
 	for h := range hch {
 		healthList = append(healthList, h)
 		if h.Error != "" {
@@ -193,7 +193,7 @@ type epStatus struct {
 func epStatusCommandFunc(cmd *cobra.Command, args []string) {
 	c := mustClientFromCmd(cmd)
 
-	statusList := []epStatus{}
+	var statusList []epStatus
 	var err error
 	for _, ep := range endpointsFromCluster(cmd) {
 		ctx, cancel := commandCtx(cmd)
@@ -222,7 +222,7 @@ type epHashKV struct {
 func epHashKVCommandFunc(cmd *cobra.Command, args []string) {
 	c := mustClientFromCmd(cmd)
 
-	hashList := []epHashKV{}
+	var hashList []epHashKV
 	var err error
 	for _, ep := range endpointsFromCluster(cmd) {
 		ctx, cancel := commandCtx(cmd)
@@ -288,7 +288,7 @@ func endpointsFromCluster(cmd *cobra.Command) []string {
 		cobrautl.ExitWithError(cobrautl.ExitError, err)
 	}
 
-	ret := []string{}
+	var ret []string
 	for _, m := range membs.Members {
 		ret = append(ret, m.ClientURLs...)
 	}

etcdctl/ctlv3/command/get_command.go

@@ -19,7 +19,7 @@ import (
 	"strings"
 
 	"github.com/spf13/cobra"
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/pkg/v3/cobrautl"
 )
 
@@ -107,7 +107,7 @@ func getGetOp(args []string) (string, []clientv3.OpOption) {
 		cobrautl.ExitWithError(cobrautl.ExitBadArgs, fmt.Errorf("`--keys-only` and `--count-only` cannot be set at the same time, choose one"))
 	}
 
-	opts := []clientv3.OpOption{}
+	var opts []clientv3.OpOption
 	switch getConsistency {
 	case "s":
 		opts = append(opts, clientv3.WithSerializable())

etcdctl/ctlv3/command/global.go

@@ -26,7 +26,7 @@ import (
 	"go.etcd.io/etcd/client/pkg/v3/logutil"
 	"go.etcd.io/etcd/client/pkg/v3/srv"
 	"go.etcd.io/etcd/client/pkg/v3/transport"
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/pkg/v3/cobrautl"
 	"go.etcd.io/etcd/pkg/v3/flags"
 
@@ -363,7 +363,7 @@ func endpointsFromFlagValue(cmd *cobra.Command) ([]string, error) {
 		return eps, err
 	}
 	// strip insecure connections
-	ret := []string{}
+	var ret []string
 	for _, ep := range eps {
 		if strings.HasPrefix(ep, "http://") {
 			fmt.Fprintf(os.Stderr, "ignoring discovered insecure endpoint %q\n", ep)

etcdctl/ctlv3/command/make_mirror_command.go

@@ -27,7 +27,7 @@ import (
 
 	"go.etcd.io/etcd/api/v3/mvccpb"
 	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/client/v3/mirror"
 
 	"github.com/spf13/cobra"
@@ -191,7 +191,7 @@ func makeMirror(ctx context.Context, c *clientv3.Client, dc *clientv3.Client) er
 		}
 
 		var lastRev int64
-		ops := []clientv3.Op{}
+		var ops []clientv3.Op
 
 		for _, ev := range wr.Events {
 			nextRev := ev.Kv.ModRevision

etcdctl/ctlv3/command/member_command.go

@@ -21,7 +21,7 @@ import (
 	"strings"
 
 	"github.com/spf13/cobra"
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/pkg/v3/cobrautl"
 )
 
@@ -157,7 +157,7 @@ func memberAddCommandFunc(cmd *cobra.Command, args []string) {
 	display.MemberAdd(*resp)
 
 	if _, ok := (display).(*simplePrinter); ok {
-		conf := []string{}
+		var conf []string
 		for _, memb := range resp.Members {
 			for _, u := range memb.PeerURLs {
 				n := memb.Name

etcdctl/ctlv3/command/put_command.go

@@ -101,7 +101,7 @@ func getPutOp(args []string) (string, string, []clientv3.OpOption) {
 		cobrautl.ExitWithError(cobrautl.ExitBadArgs, fmt.Errorf("bad lease ID (%v), expecting ID in Hex", err))
 	}
 
-	opts := []clientv3.OpOption{}
+	var opts []clientv3.OpOption
 	if id != 0 {
 		opts = append(opts, clientv3.WithLease(clientv3.LeaseID(id)))
 	}

pkg/osutil/interrupt_unix.go

@@ -36,7 +36,7 @@ var (
 	interruptRegisterMu, interruptExitMu sync.Mutex
 	// interruptHandlers holds all registered InterruptHandlers in order
 	// they will be executed.
-	interruptHandlers = []InterruptHandler{}
+	interruptHandlers []InterruptHandler
 )
 
 // RegisterInterruptHandler registers a new InterruptHandler. Handlers registered

pkg/report/timeseries.go

@@ -124,7 +124,7 @@ func (t TimeSeries) String() string {
 	if err := wr.Write([]string{"UNIX-SECOND", "MIN-LATENCY-MS", "AVG-LATENCY-MS", "MAX-LATENCY-MS", "AVG-THROUGHPUT"}); err != nil {
 		log.Fatal(err)
 	}
-	rows := [][]string{}
+	var rows [][]string
 	for i := range t {
 		row := []string{
 			fmt.Sprintf("%d", t[i].Timestamp),

raft/node_test.go

@@ -124,7 +124,7 @@ func TestNodeStepUnblock(t *testing.T) {
 
 // TestNodePropose ensures that node.Propose sends the given proposal to the underlying raft.
 func TestNodePropose(t *testing.T) {
-	msgs := []raftpb.Message{}
+	var msgs []raftpb.Message
 	appendStep := func(r *raft, m raftpb.Message) error {
 		msgs = append(msgs, m)
 		return nil
@@ -166,7 +166,7 @@ func TestNodePropose(t *testing.T) {
 // TestNodeReadIndex ensures that node.ReadIndex sends the MsgReadIndex message to the underlying raft.
 // It also ensures that ReadState can be read out through ready chan.
 func TestNodeReadIndex(t *testing.T) {
-	msgs := []raftpb.Message{}
+	var msgs []raftpb.Message
 	appendStep := func(r *raft, m raftpb.Message) error {
 		msgs = append(msgs, m)
 		return nil
@@ -306,7 +306,7 @@ func TestNodeReadIndexToOldLeader(t *testing.T) {
 // TestNodeProposeConfig ensures that node.ProposeConfChange sends the given configuration proposal
 // to the underlying raft.
 func TestNodeProposeConfig(t *testing.T) {
-	msgs := []raftpb.Message{}
+	var msgs []raftpb.Message
 	appendStep := func(r *raft, m raftpb.Message) error {
 		msgs = append(msgs, m)
 		return nil
@@ -456,7 +456,7 @@ func TestBlockProposal(t *testing.T) {
 }
 
 func TestNodeProposeWaitDropped(t *testing.T) {
-	msgs := []raftpb.Message{}
+	var msgs []raftpb.Message
 	droppingMsg := []byte("test_dropping")
 	dropStep := func(r *raft, m raftpb.Message) error {
 		if m.Type == raftpb.MsgProp && strings.Contains(m.String(), string(droppingMsg)) {

raft/raft_test.go

@@ -640,13 +640,13 @@ func TestLogReplication(t *testing.T) {
 				t.Errorf("#%d.%d: committed = %d, want %d", i, j, sm.raftLog.committed, tt.wcommitted)
 			}
 
-			ents := []pb.Entry{}
+			var ents []pb.Entry
 			for _, e := range nextEnts(sm, tt.network.storage[j]) {
 				if e.Data != nil {
 					ents = append(ents, e)
 				}
 			}
-			props := []pb.Message{}
+			var props []pb.Message
 			for _, m := range tt.msgs {
 				if m.Type == pb.MsgProp {
 					props = append(props, m)
@@ -4747,7 +4747,7 @@ func (nw *network) recover() {
 }
 
 func (nw *network) filter(msgs []pb.Message) []pb.Message {
-	mm := []pb.Message{}
+	var mm []pb.Message
 	for _, m := range msgs {
 		if nw.ignorem[m.Type] {
 			continue

raft/rawnode_test.go

@@ -585,7 +585,7 @@ func TestRawNodeProposeAddDuplicateNode(t *testing.T) {
 // TestRawNodeReadIndex ensures that Rawnode.ReadIndex sends the MsgReadIndex message
 // to the underlying raft. It also ensures that ReadState can be read out.
 func TestRawNodeReadIndex(t *testing.T) {
-	msgs := []pb.Message{}
+	var msgs []pb.Message
 	appendStep := func(r *raft, m pb.Message) error {
 		msgs = append(msgs, m)
 		return nil

raft/read_only.go

@@ -85,7 +85,7 @@ func (ro *readOnly) advance(m pb.Message) []*readIndexStatus {
 	)
 
 	ctx := string(m.Context)
-	rss := []*readIndexStatus{}
+	var rss []*readIndexStatus
 
 	for _, okctx := range ro.readIndexQueue {
 		i++

server/auth/store_mock_test.go

@@ -85,15 +85,15 @@ func (t txMock) UnsafeGetRole(s string) *authpb.Role {
 }
 
 func (t txMock) UnsafeGetAllUsers() []*authpb.User {
-	users := []*authpb.User{}
+	var users []*authpb.User
 	for _, u := range t.be.users {
 		users = append(users, u)
 	}
 	return users
 }
 
 func (t txMock) UnsafeGetAllRoles() []*authpb.Role {
-	roles := []*authpb.Role{}
+	var roles []*authpb.Role
 	for _, r := range t.be.roles {
 		roles = append(roles, r)
 	}

server/config/config.go

@@ -271,7 +271,7 @@ func (c *ServerConfig) advertiseMatchesCluster() error {
 		initMap[url.String()] = struct{}{}
 	}
 
-	missing := []string{}
+	var missing []string
 	for url := range initMap {
 		if _, ok := apMap[url]; !ok {
 			missing = append(missing, url)

server/embed/etcd.go

@@ -708,7 +708,7 @@ func (e *Etcd) serveClients() (err error) {
 	etcdhttp.HandleMetrics(mux)
 	etcdhttp.HandleHealth(e.cfg.logger, mux, e.Server)
 
-	gopts := []grpc.ServerOption{}
+	var gopts []grpc.ServerOption
 	if e.cfg.GRPCKeepAliveMinTime > time.Duration(0) {
 		gopts = append(gopts, grpc.KeepaliveEnforcementPolicy(keepalive.EnforcementPolicy{
 			MinTime:             e.cfg.GRPCKeepAliveMinTime,

server/etcdserver/api/snap/snapshotter.go

@@ -220,7 +220,7 @@ func (s *Snapshotter) snapNames() ([]string, error) {
 }
 
 func (s *Snapshotter) checkSuffix(names []string) []string {
-	snaps := []string{}
+	var snaps []string
 	for i := range names {
 		if strings.HasSuffix(names[i], snapSuffix) {
 			snaps = append(snaps, names[i])

server/etcdserver/server_test.go

@@ -748,7 +748,7 @@ func TestApplyMultiConfChangeShouldStop(t *testing.T) {
 		consistIndex: ci,
 		beHooks:      serverstorage.NewBackendHooks(lg, ci),
 	}
-	ents := []raftpb.Entry{}
+	var ents []raftpb.Entry
 	for i := 1; i <= 4; i++ {
 		ent := raftpb.Entry{
 			Term:  1,

server/etcdserver/txn/txn.go

@@ -575,7 +575,7 @@ func compareKV(c *pb.Compare, ckv mvccpb.KeyValue) bool {
 	rev := int64(0)
 	switch c.Target {
 	case pb.Compare_VALUE:
-		v := []byte{}
+		var v []byte
 		if tv, _ := c.TargetUnion.(*pb.Compare_Value); tv != nil {
 			v = tv.Value
 		}

server/etcdserver/version/version_test.go

@@ -143,7 +143,7 @@ func newCluster(lg *zap.Logger, memberCount int, ver semver.Version) *clusterMoc
 
 func (c *clusterMock) StepMonitors() {
 	// Execute monitor functions in random order as it is not guaranteed
-	fs := []func(){}
+	var fs []func()
 	for _, m := range c.members {
 		fs = append(fs, m.monitor.UpdateStorageVersionIfNeeded)
 		if m.isLeader {

server/lease/lessor.go

@@ -759,7 +759,7 @@ func (le *lessor) findDueScheduledCheckpoints(checkpointLimit int) []*pb.LeaseCh
 	}
 
 	now := time.Now()
-	cps := []*pb.LeaseCheckpoint{}
+	var cps []*pb.LeaseCheckpoint
 	for le.leaseCheckpointHeap.Len() > 0 && len(cps) < checkpointLimit {
 		lt := le.leaseCheckpointHeap[0]
 		if lt.time.After(now) /* lt.time: next checkpoint time */ {