Merge pull request #14479 from demoManito/fix/declaring-empty-slice

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

@@ -85,7 +85,7 @@ 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)
 	}
@@ -93,7 +93,7 @@ func (t txMock) UnsafeGetAllUsers() []*authpb.User {
 }
 
 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 */ {

server/proxy/grpcproxy/kv.go

@@ -18,7 +18,7 @@ import (
 	"context"
 
 	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/server/v3/proxy/grpcproxy/cache"
 )
 
@@ -162,7 +162,7 @@ func requestOpToOp(union *pb.RequestOp) clientv3.Op {
 }
 
 func RangeRequestToOp(r *pb.RangeRequest) clientv3.Op {
-	opts := []clientv3.OpOption{}
+	var opts []clientv3.OpOption
 	if len(r.RangeEnd) != 0 {
 		opts = append(opts, clientv3.WithRange(string(r.RangeEnd)))
 	}
@@ -190,7 +190,7 @@ func RangeRequestToOp(r *pb.RangeRequest) clientv3.Op {
 }
 
 func PutRequestToOp(r *pb.PutRequest) clientv3.Op {
-	opts := []clientv3.OpOption{}
+	var opts []clientv3.OpOption
 	opts = append(opts, clientv3.WithLease(clientv3.LeaseID(r.Lease)))
 	if r.IgnoreValue {
 		opts = append(opts, clientv3.WithIgnoreValue())
@@ -205,7 +205,7 @@ func PutRequestToOp(r *pb.PutRequest) clientv3.Op {
 }
 
 func DelRequestToOp(r *pb.DeleteRangeRequest) clientv3.Op {
-	opts := []clientv3.OpOption{}
+	var opts []clientv3.OpOption
 	if len(r.RangeEnd) != 0 {
 		opts = append(opts, clientv3.WithRange(string(r.RangeEnd)))
 	}

server/proxy/tcpproxy/userspace.go

@@ -96,7 +96,7 @@ func (tp *TCPProxy) Run() error {
 		tp.remotes = append(tp.remotes, &remote{srv: srv, addr: addr})
 	}
 
-	eps := []string{}
+	var eps []string
 	for _, ep := range tp.Endpoints {
 		eps = append(eps, fmt.Sprintf("%s:%d", ep.Target, ep.Port))
 	}

server/storage/mvcc/kvstore_test.go

@@ -1009,7 +1009,7 @@ func (i *fakeIndex) KeyIndex(ki *keyIndex) *keyIndex {
 }
 
 func createBytesSlice(bytesN, sliceN int) [][]byte {
-	rs := [][]byte{}
+	var rs [][]byte
 	for len(rs) != sliceN {
 		v := make([]byte, bytesN)
 		if _, err := rand.Read(v); err != nil {

server/storage/mvcc/testutil/hash.go

@@ -120,7 +120,8 @@ func CorruptBBolt(fpath string) error {
 		if b == nil {
 			return errors.New("got nil bucket for 'key'")
 		}
-		keys, vals := [][]byte{}, [][]byte{}
+		var vals [][]byte
+		var keys [][]byte
 		c := b.Cursor()
 		for k, v := c.First(); k != nil; k, v = c.Next() {
 			keys = append(keys, k)

server/storage/schema/alarm.go

@@ -79,7 +79,7 @@ func (s *alarmBackend) GetAllAlarms() ([]*etcdserverpb.AlarmMember, error) {
 }
 
 func (s *alarmBackend) unsafeGetAllAlarms(tx backend.ReadTx) ([]*etcdserverpb.AlarmMember, error) {
-	ms := []*etcdserverpb.AlarmMember{}
+	var ms []*etcdserverpb.AlarmMember
 	err := tx.UnsafeForEach(Alarm, func(k, v []byte) error {
 		var m etcdserverpb.AlarmMember
 		if err := m.Unmarshal(k); err != nil {

server/storage/wal/decoder.go

@@ -139,7 +139,7 @@ func (d *decoder) isTornEntry(data []byte) bool {
 
 	fileOff := d.lastValidOff + frameSizeBytes
 	curOff := 0
-	chunks := [][]byte{}
+	var chunks [][]byte
 	// split data on sector boundaries
 	for curOff < len(data) {
 		chunkLen := int(minSectorSize - (fileOff % minSectorSize))

server/storage/wal/testing/waltesting.go

@@ -52,7 +52,7 @@ func NewTmpWAL(t testing.TB, reqs []etcdserverpb.InternalRaftRequest) (*wal.WAL,
 		if err != nil {
 			t.Fatalf("Failed to read WAL: %v", err)
 		}
-		entries := []raftpb.Entry{}
+		var entries []raftpb.Entry
 		for _, req := range reqs {
 			entries = append(entries, raftpb.Entry{
 				Term:  1,

tests/common/lease_test.go

@@ -106,7 +106,7 @@ func TestLeaseGrantAndList(t *testing.T) {
 				cc := clus.Client()
 				t.Logf("Created cluster and client")
 				testutils.ExecuteUntil(ctx, t, func() {
-					createdLeases := []clientv3.LeaseID{}
+					var createdLeases []clientv3.LeaseID
 					for i := 0; i < nc.leaseCount; i++ {
 						leaseResp, err := cc.Grant(ctx, 10)
 						t.Logf("Grant returned: resp:%s err:%v", leaseResp.String(), err)
@@ -117,7 +117,7 @@ func TestLeaseGrantAndList(t *testing.T) {
 					// Because we're not guarunteed to talk to the same member, wait for
 					// listing to eventually return true, either by the result propagaing
 					// or by hitting an up to date member.
-					leases := []clientv3.LeaseStatus{}
+					var leases []clientv3.LeaseStatus
 					require.Eventually(t, func() bool {
 						resp, err := cc.Leases(ctx)
 						if err != nil {

tests/common/txn_test.go

@@ -124,7 +124,7 @@ func TestTxnFail(t *testing.T) {
 }
 
 func getRespValues(r *clientv3.TxnResponse) []string {
-	ss := []string{}
+	var ss []string
 	if r.Succeeded {
 		ss = append(ss, "SUCCESS")
 	} else {

tests/e2e/ctl_v3_grpc_test.go

@@ -120,7 +120,7 @@ func TestAuthority(t *testing.T) {
 
 func templateEndpoints(t *testing.T, pattern string, clus *e2e.EtcdProcessCluster) []string {
 	t.Helper()
-	endpoints := []string{}
+	var endpoints []string
 	for i := 0; i < clus.Cfg.ClusterSize; i++ {
 		ent := pattern
 		if strings.Contains(ent, "%d") {
@@ -135,7 +135,7 @@ func templateEndpoints(t *testing.T, pattern string, clus *e2e.EtcdProcessCluste
 }
 
 func assertAuthority(t *testing.T, expectAurhority string, clus *e2e.EtcdProcessCluster) {
-	logs := []e2e.LogsExpect{}
+	var logs []e2e.LogsExpect
 	for _, proc := range clus.Procs {
 		logs = append(logs, proc.Logs())
 	}

tests/e2e/ctl_v3_make_mirror_test.go

@@ -30,7 +30,7 @@ func TestCtlV3MakeMirrorWithWatchRev(t *testing.T)     { testCtl(t, makeMirrorWi
 
 func makeMirrorTest(cx ctlCtx) {
 	var (
-		flags  = []string{}
+		flags  []string
 		kvs    = []kv{{"key1", "val1"}, {"key2", "val2"}, {"key3", "val3"}}
 		kvs2   = []kvExec{{key: "key1", val: "val1"}, {key: "key2", val: "val2"}, {key: "key3", val: "val3"}}
 		prefix = "key"

tests/framework/integration.go

@@ -135,7 +135,7 @@ func (c integrationClient) Get(ctx context.Context, key string, o config.GetOpti
 		ctx, cancel = context.WithTimeout(ctx, o.Timeout)
 		defer cancel()
 	}
-	clientOpts := []clientv3.OpOption{}
+	var clientOpts []clientv3.OpOption
 	if o.Revision != 0 {
 		clientOpts = append(clientOpts, clientv3.WithRev(int64(o.Revision)))
 	}
@@ -164,7 +164,7 @@ func (c integrationClient) Get(ctx context.Context, key string, o config.GetOpti
 }
 
 func (c integrationClient) Put(ctx context.Context, key, value string, opts config.PutOptions) error {
-	clientOpts := []clientv3.OpOption{}
+	var clientOpts []clientv3.OpOption
 	if opts.LeaseID != 0 {
 		clientOpts = append(clientOpts, clientv3.WithLease(opts.LeaseID))
 	}
@@ -173,7 +173,7 @@ func (c integrationClient) Put(ctx context.Context, key, value string, opts conf
 }
 
 func (c integrationClient) Delete(ctx context.Context, key string, o config.DeleteOptions) (*clientv3.DeleteResponse, error) {
-	clientOpts := []clientv3.OpOption{}
+	var clientOpts []clientv3.OpOption
 	if o.Prefix {
 		clientOpts = append(clientOpts, clientv3.WithPrefix())
 	}
@@ -192,7 +192,7 @@ func (c integrationClient) Compact(ctx context.Context, rev int64, o config.Comp
 		ctx, cancel = context.WithTimeout(ctx, o.Timeout)
 		defer cancel()
 	}
-	clientOpts := []clientv3.CompactOption{}
+	var clientOpts []clientv3.CompactOption
 	if o.Physical {
 		clientOpts = append(clientOpts, clientv3.WithCompactPhysical())
 	}
@@ -253,7 +253,7 @@ func (c integrationClient) Defragment(ctx context.Context, o config.DefragOption
 }
 
 func (c integrationClient) TimeToLive(ctx context.Context, id clientv3.LeaseID, o config.LeaseOption) (*clientv3.LeaseTimeToLiveResponse, error) {
-	leaseOpts := []clientv3.LeaseOption{}
+	var leaseOpts []clientv3.LeaseOption
 	if o.WithAttachedKeys {
 		leaseOpts = append(leaseOpts, clientv3.WithAttachedKeys())
 	}
@@ -274,7 +274,7 @@ func (c integrationClient) UserChangePass(ctx context.Context, user, newPass str
 
 func (c integrationClient) Txn(ctx context.Context, compares, ifSucess, ifFail []string, o config.TxnOptions) (*clientv3.TxnResponse, error) {
 	txn := c.Client.Txn(ctx)
-	cmps := []clientv3.Cmp{}
+	var cmps []clientv3.Cmp
 	for _, c := range compares {
 		cmp, err := etcdctlcmd.ParseCompare(c)
 		if err != nil {
@@ -299,7 +299,7 @@ func (c integrationClient) Txn(ctx context.Context, compares, ifSucess, ifFail [
 }
 
 func getOps(ss []string) ([]clientv3.Op, error) {
-	ops := []clientv3.Op{}
+	var ops []clientv3.Op
 	for _, s := range ss {
 		s = strings.TrimSpace(s)
 		args := etcdctlcmd.Argify(s)
@@ -316,7 +316,7 @@ func getOps(ss []string) ([]clientv3.Op, error) {
 }
 
 func (c integrationClient) Watch(ctx context.Context, key string, opts config.WatchOptions) clientv3.WatchChan {
-	opOpts := []clientv3.OpOption{}
+	var opOpts []clientv3.OpOption
 	if opts.Prefix {
 		opOpts = append(opOpts, clientv3.WithPrefix())
 	}

tests/framework/integration/cluster.go

@@ -39,7 +39,7 @@ import (
 	"go.etcd.io/etcd/client/pkg/v3/tlsutil"
 	"go.etcd.io/etcd/client/pkg/v3/transport"
 	"go.etcd.io/etcd/client/pkg/v3/types"
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/pkg/v3/grpc_testing"
 	"go.etcd.io/etcd/raft/v3"
 	"go.etcd.io/etcd/server/v3/config"
@@ -240,7 +240,7 @@ func (c *Cluster) Launch(t testutil.TB) {
 
 // ProtoMembers returns a list of all active members as client.Members
 func (c *Cluster) ProtoMembers() []*pb.Member {
-	ms := []*pb.Member{}
+	var ms []*pb.Member
 	for _, m := range c.Members {
 		pScheme := SchemeFromTLSInfo(m.PeerTLSInfo)
 		cScheme := SchemeFromTLSInfo(m.ClientTLSInfo)

tests/functional/tester/case_sigquit_remove.go

@@ -21,7 +21,7 @@ import (
 	"strings"
 	"time"
 
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/tests/v3/functional/rpcpb"
 
 	"go.uber.org/zap"
@@ -36,7 +36,7 @@ func inject_SIGQUIT_ETCD_AND_REMOVE_DATA(clus *Cluster, idx1 int) error {
 
 	var mresp *clientv3.MemberListResponse
 	mresp, err = cli1.MemberList(context.Background())
-	mss := []string{}
+	var mss []string
 	if err == nil && mresp != nil {
 		mss = describeMembers(mresp)
 	}
@@ -161,7 +161,7 @@ func recover_SIGQUIT_ETCD_AND_REMOVE_DATA(clus *Cluster, idx1 int) error {
 
 	var mresp *clientv3.MemberListResponse
 	mresp, err = cli2.MemberList(context.Background())
-	mss := []string{}
+	var mss []string
 	if err == nil && mresp != nil {
 		mss = describeMembers(mresp)
 	}

tests/functional/tester/case_sigquit_remove_quorum.go

@@ -20,7 +20,7 @@ import (
 	"strings"
 	"time"
 
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/tests/v3/functional/rpcpb"
 
 	"go.uber.org/zap"
@@ -82,7 +82,7 @@ func (c *fetchSnapshotCaseQuorum) Inject(clus *Cluster) error {
 	defer leaderc.Close()
 	var mresp *clientv3.MemberListResponse
 	mresp, err = leaderc.MemberList(context.Background())
-	mss := []string{}
+	var mss []string
 	if err == nil && mresp != nil {
 		mss = describeMembers(mresp)
 	}
@@ -148,7 +148,7 @@ func (c *fetchSnapshotCaseQuorum) Recover(clus *Cluster) error {
 	clus.Members[oldlead].EtcdOnSnapshotRestore = clus.Members[oldlead].Etcd
 	clus.Members[oldlead].EtcdOnSnapshotRestore.InitialClusterState = "existing"
 	name := clus.Members[oldlead].Etcd.Name
-	initClus := []string{}
+	var initClus []string
 	for _, u := range clus.Members[oldlead].Etcd.AdvertisePeerURLs {
 		initClus = append(initClus, fmt.Sprintf("%s=%s", name, u))
 	}

tests/functional/tester/cluster.go

@@ -296,8 +296,8 @@ func (clus *Cluster) UpdateDelayLatencyMs() {
 
 func (clus *Cluster) setStresserChecker() {
 	css := &compositeStresser{}
-	lss := []*leaseStresser{}
-	rss := []*runnerStresser{}
+	var lss []*leaseStresser
+	var rss []*runnerStresser
 	for _, m := range clus.Members {
 		sss := newStresser(clus, m)
 		css.stressers = append(css.stressers, &compositeStresser{sss})
@@ -419,7 +419,7 @@ func (clus *Cluster) broadcast(op rpcpb.Operation) error {
 	wg.Wait()
 	close(errc)
 
-	errs := []string{}
+	var errs []string
 	for err := range errc {
 		if err == nil {
 			continue

tests/functional/tester/cluster_run.go

@@ -258,7 +258,7 @@ func (clus *Cluster) doTestCase(t *testing.T, fa Case) {
 		t.Fatalf("wait full health error: %v", err)
 	}
 
-	checkerFailExceptions := []rpcpb.Checker{}
+	var checkerFailExceptions []rpcpb.Checker
 	switch fcase {
 	case rpcpb.Case_SIGQUIT_AND_REMOVE_QUORUM_AND_RESTORE_LEADER_SNAPSHOT_FROM_SCRATCH:
 		// TODO: restore from snapshot

tests/integration/clientv3/kv_test.go

@@ -28,7 +28,7 @@ import (
 	"go.etcd.io/etcd/api/v3/mvccpb"
 	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
 	"go.etcd.io/etcd/api/v3/version"
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	integration2 "go.etcd.io/etcd/tests/v3/framework/integration"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
@@ -353,17 +353,15 @@ func TestKVDeleteRange(t *testing.T) {
 	ctx := context.TODO()
 
 	tests := []struct {
-		key  string
-		opts []clientv3.OpOption
-
+		key   string
+		opts  []clientv3.OpOption
 		wkeys []string
 	}{
 		// *
 		{
-			key:  "\x00",
-			opts: []clientv3.OpOption{clientv3.WithFromKey()},
-
-			wkeys: []string{},
+			key:   "\x00",
+			opts:  []clientv3.OpOption{clientv3.WithFromKey()},
+			wkeys: nil,
 		},
 	}
 
@@ -384,7 +382,7 @@ func TestKVDeleteRange(t *testing.T) {
 		if err != nil {
 			t.Fatalf("#%d: couldn't get keys (%v)", i, err)
 		}
-		keys := []string{}
+		var keys []string
 		for _, kv := range resp.Kvs {
 			keys = append(keys, string(kv.Key))
 		}

tests/integration/clientv3/lease/lease_test.go

@@ -24,7 +24,7 @@ import (
 	"time"
 
 	"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/concurrency"
 	integration2 "go.etcd.io/etcd/tests/v3/framework/integration"
 )
@@ -249,7 +249,7 @@ func TestLeaseKeepAliveNotFound(t *testing.T) {
 	defer clus.Terminate(t)
 
 	cli := clus.RandClient()
-	lchs := []leaseCh{}
+	var lchs []leaseCh
 	for i := 0; i < 3; i++ {
 		resp, rerr := cli.Grant(context.TODO(), 5)
 		if rerr != nil {
@@ -628,7 +628,7 @@ func TestLeaseLeases(t *testing.T) {
 
 	cli := clus.RandClient()
 
-	ids := []clientv3.LeaseID{}
+	var ids []clientv3.LeaseID
 	for i := 0; i < 5; i++ {
 		resp, err := cli.Grant(context.Background(), 10)
 		if err != nil {

tests/integration/clientv3/lease/leasing_test.go

@@ -357,7 +357,7 @@ func TestLeasingGetWithOpts(t *testing.T) {
 		}
 	}
 
-	getOpts := []clientv3.OpOption{}
+	var getOpts []clientv3.OpOption
 	for i := 0; i < len(opts); i++ {
 		getOpts = append(getOpts, opts[rand.Intn(len(opts))])
 	}
@@ -963,7 +963,7 @@ func TestLeasingTxnNonOwnerPut(t *testing.T) {
 		clientv3.WithPrefix())
 	wresp := <-w
 	c := 0
-	evs := []clientv3.Event{}
+	var evs []clientv3.Event
 	for _, ev := range wresp.Events {
 		evs = append(evs, *ev)
 		if ev.Kv.ModRevision == tresp.Header.Revision {
@@ -1021,7 +1021,7 @@ func TestLeasingTxnRandIfThenOrElse(t *testing.T) {
 	// random list of comparisons, all true
 	cmps, useThen := randCmps("k-", dat)
 	// random list of puts/gets; unique keys
-	ops := []clientv3.Op{}
+	var ops []clientv3.Op
 	usedIdx := make(map[int]struct{})
 	for i := 0; i < keyCount; i++ {
 		idx := rand.Intn(keyCount)

tests/integration/clientv3/metrics_test.go

@@ -28,7 +28,7 @@ import (
 	grpcprom "github.com/grpc-ecosystem/go-grpc-prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"go.etcd.io/etcd/client/pkg/v3/transport"
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	integration2 "go.etcd.io/etcd/tests/v3/framework/integration"
 	"google.golang.org/grpc"
 )
@@ -162,7 +162,7 @@ func getHTTPBodyAsLines(t *testing.T, url string) []string {
 	}
 
 	reader := bufio.NewReader(resp.Body)
-	lines := []string{}
+	var lines []string
 	for {
 		line, err := reader.ReadString('\n')
 		if err != nil {

tests/integration/clientv3/snapshot/v3_snapshot_test.go

@@ -26,7 +26,7 @@ import (
 
 	"go.etcd.io/etcd/client/pkg/v3/fileutil"
 	"go.etcd.io/etcd/client/pkg/v3/testutil"
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/client/v3/snapshot"
 	"go.etcd.io/etcd/server/v3/embed"
 	integration2 "go.etcd.io/etcd/tests/v3/framework/integration"
@@ -55,7 +55,7 @@ func TestSaveSnapshotFilePermissions(t *testing.T) {
 // TestSaveSnapshotVersion ensures that the snapshot returns proper storage version.
 func TestSaveSnapshotVersion(t *testing.T) {
 	// Put some keys to ensure that wal snapshot is triggered
-	kvs := []kv{}
+	var kvs []kv
 	for i := 0; i < 10; i++ {
 		kvs = append(kvs, kv{fmt.Sprintf("%d", i), "test"})
 	}

tests/integration/clientv3/watch_test.go

@@ -110,7 +110,7 @@ func testWatchMultiWatcher(t *testing.T, wctx *watchctx) {
 			t.Errorf("expected watcher channel, got nil")
 		}
 		readyc <- struct{}{}
-		evs := []*clientv3.Event{}
+		var evs []*clientv3.Event
 		for i := 0; i < numKeyUpdates*2; i++ {
 			resp, ok := <-prefixc
 			if !ok {
@@ -120,14 +120,14 @@ func testWatchMultiWatcher(t *testing.T, wctx *watchctx) {
 		}
 
 		// check response
-		expected := []string{}
+		var expected []string
 		bkeys := []string{"bar", "baz"}
 		for _, k := range bkeys {
 			for i := 0; i < numKeyUpdates; i++ {
 				expected = append(expected, fmt.Sprintf("%s-%d", k, i))
 			}
 		}
-		got := []string{}
+		var got []string
 		for _, ev := range evs {
 			got = append(got, string(ev.Kv.Value))
 		}

tests/integration/grpc_test.go

@@ -150,7 +150,7 @@ func setupClient(t *testing.T, endpointPattern string, clus *integration.Cluster
 
 func templateEndpoints(t *testing.T, pattern string, clus *integration.Cluster) []string {
 	t.Helper()
-	endpoints := []string{}
+	var endpoints []string
 	for _, m := range clus.Members {
 		ent := pattern
 		if strings.Contains(ent, "%d") {

tests/integration/v3_election_test.go

@@ -20,7 +20,7 @@ import (
 	"testing"
 	"time"
 
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/client/v3/concurrency"
 	"go.etcd.io/etcd/tests/v3/framework/integration"
 )
@@ -40,7 +40,7 @@ func TestElectionWait(t *testing.T) {
 	}()
 
 	electedc := make(chan string)
-	nextc := []chan struct{}{}
+	var nextc []chan struct{}
 
 	// wait for all elections
 	donec := make(chan struct{})

tests/integration/v3_grpc_test.go

@@ -28,7 +28,7 @@ import (
 	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
 	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
 	"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/tests/v3/framework/config"
 	"go.etcd.io/etcd/tests/v3/framework/integration"
 
@@ -1111,7 +1111,7 @@ func TestV3DeleteRange(t *testing.T) {
 					dresp.Header.Revision, rresp.Header.Revision)
 			}
 
-			keys := [][]byte{}
+			var keys [][]byte
 			for j := range rresp.Kvs {
 				keys = append(keys, rresp.Kvs[j].Key)
 			}

tests/integration/v3_lease_test.go

@@ -458,7 +458,7 @@ func TestV3LeaseLeases(t *testing.T) {
 	defer cancel0()
 
 	// create leases
-	ids := []int64{}
+	var ids []int64
 	for i := 0; i < 5; i++ {
 		lresp, err := integration.ToGRPC(clus.RandClient()).Lease.LeaseGrant(
 			ctx0,

tests/integration/v3_stm_test.go

@@ -174,7 +174,7 @@ func TestSTMSerialize(t *testing.T) {
 		defer close(updatec)
 		for i := 0; i < 5; i++ {
 			s := fmt.Sprintf("%d", i)
-			ops := []v3.Op{}
+			var ops []v3.Op
 			for _, k := range keys {
 				ops = append(ops, v3.OpPut(k, s))
 			}
@@ -190,7 +190,7 @@ func TestSTMSerialize(t *testing.T) {
 	for range updatec {
 		curEtcdc := clus.RandClient()
 		applyf := func(stm concurrency.STM) error {
-			vs := []string{}
+			var vs []string
 			for i := range keys {
 				vs = append(vs, stm.Get(keys[i]))
 			}

tests/integration/v3_watch_test.go

@@ -748,7 +748,7 @@ func testV3WatchMultipleEventsTxn(t *testing.T, startRev int64) {
 		t.Fatalf("kvc.Txn failed: %+v", tresp)
 	}
 
-	events := []*mvccpb.Event{}
+	var events []*mvccpb.Event
 	for len(events) < 3 {
 		resp, err := wStream.Recv()
 		if err != nil {
@@ -845,7 +845,7 @@ func TestV3WatchMultipleEventsPutUnsynced(t *testing.T) {
 		},
 	}
 
-	events := []*mvccpb.Event{}
+	var events []*mvccpb.Event
 	for len(events) < 4 {
 		resp, err := wStream.Recv()
 		if err != nil {

tools/local-tester/bridge/dispatch.go

@@ -70,7 +70,7 @@ func (d *dispatcherPool) flush() {
 
 	// sort by sockets; preserve the packet ordering within a socket
 	pktmap := make(map[io.Writer][]dispatchPacket)
-	outs := []io.Writer{}
+	var outs []io.Writer
 	for _, pkt := range pkts {
 		opkts, ok := pktmap[pkt.out]
 		if !ok {
@@ -103,7 +103,7 @@ func (d *dispatcherPool) Copy(w io.Writer, f fetchFunc) error {
 			return err
 		}
 
-		pkts := []dispatchPacket{}
+		var pkts []dispatchPacket
 		for len(b) > 0 {
 			pkt := b
 			if len(b) > dispatchPacketBytes {