*: fix unparam lint

Signed-off-by: Wei Fu <fuweid89@gmail.com>

Makefile

@@ -65,7 +65,7 @@ fuzz:
 verify: verify-gofmt verify-bom verify-lint verify-dep verify-shellcheck verify-goword \
 	verify-govet verify-license-header verify-receiver-name verify-mod-tidy verify-shellcheck \
 	verify-shellws verify-proto-annotations verify-genproto verify-goimport verify-yamllint \
-	verify-govet-shadow
+	verify-govet-shadow verify-unparam-lint
 fix: fix-goimports fix-bom fix-lint fix-yamllint
 	./scripts/fix.sh
 
@@ -85,8 +85,13 @@ fix-bom:
 verify-dep:
 	PASSES="dep" ./scripts/test.sh
 
+# TODO: https://github.com/etcd-io/etcd/issues/16610
+#
+# The golangci-lint doesn't verify sub modules. Before #16610 fixed, verify-lint
+# still depends on legacy {ineffassign,nakedret,unparam,...}_pass. These X_pass
+# will be removed when the golangci-lint covers all the sub modules.
 .PHONY: verify-lint
-verify-lint:
+verify-lint: verify-unparam-lint
 	golangci-lint run --config tools/.golangci.yaml
 
 .PHONY: fix-lint
@@ -145,6 +150,10 @@ verify-yamllint:
 verify-govet-shadow:
 	PASSES="govet_shadow" ./scripts/test.sh
 
+.PHONY: verify-unparam-lint
+verify-unparam-lint:
+	PASSES="unparam" ./scripts/test.sh
+
 YAMLFMT_VERSION = $(shell cd tools/mod && go list -m -f '{{.Version}}' github.com/google/yamlfmt)
 
 .PHONY: fix-yamllint

client/internal/v2/cancelreq.go

@@ -8,7 +8,7 @@ package client
 
 import "net/http"
 
-func requestCanceler(tr CancelableTransport, req *http.Request) func() {
+func requestCanceler(req *http.Request) func() {
 	ch := make(chan struct{})
 	req.Cancel = ch
 

client/internal/v2/client.go

@@ -556,7 +556,7 @@ func (c *simpleHTTPClient) Do(ctx context.Context, act httpAction) (*http.Respon
 	}
 	defer hcancel()
 
-	reqcancel := requestCanceler(c.transport, req)
+	reqcancel := requestCanceler(req)
 
 	rtchan := make(chan roundTripResponse, 1)
 	go func() {

client/pkg/transport/listener.go

@@ -60,11 +60,7 @@ func newListener(addr, scheme string, opts ...ListenerOption) (net.Listener, err
 	switch {
 	case lnOpts.IsSocketOpts():
 		// new ListenConfig with socket options.
-		config, err := newListenConfig(lnOpts.socketOpts)
-		if err != nil {
-			return nil, err
-		}
-		lnOpts.ListenConfig = config
+		lnOpts.ListenConfig = newListenConfig(lnOpts.socketOpts)
 		// check for timeout
 		fallthrough
 	case lnOpts.IsTimeout(), lnOpts.IsSocketOpts():
@@ -129,15 +125,15 @@ func wrapTLS(scheme string, tlsinfo *TLSInfo, l net.Listener) (net.Listener, err
 	return newTLSListener(l, tlsinfo, checkSAN)
 }
 
-func newListenConfig(sopts *SocketOpts) (net.ListenConfig, error) {
+func newListenConfig(sopts *SocketOpts) net.ListenConfig {
 	lc := net.ListenConfig{}
 	if sopts != nil {
 		ctls := getControls(sopts)
 		if len(ctls) > 0 {
 			lc.Control = ctls.Control
 		}
 	}
-	return lc, nil
+	return lc
 }
 
 type TLSInfo struct {

client/v3/client.go

@@ -220,7 +220,9 @@ func (c *Client) autoSync() {
 }
 
 // dialSetupOpts gives the dial opts prior to any authentication.
-func (c *Client) dialSetupOpts(creds grpccredentials.TransportCredentials, dopts ...grpc.DialOption) (opts []grpc.DialOption, err error) {
+func (c *Client) dialSetupOpts(creds grpccredentials.TransportCredentials, dopts ...grpc.DialOption) []grpc.DialOption {
+	var opts []grpc.DialOption
+
 	if c.cfg.DialKeepAliveTime > 0 {
 		params := keepalive.ClientParameters{
 			Time:                c.cfg.DialKeepAliveTime,
@@ -248,7 +250,7 @@ func (c *Client) dialSetupOpts(creds grpccredentials.TransportCredentials, dopts
 		grpc.WithUnaryInterceptor(c.unaryClientInterceptor(withMax(defaultUnaryMaxRetries), rrBackoff)),
 	)
 
-	return opts, nil
+	return opts
 }
 
 // Dial connects to a single endpoint using the client's config.
@@ -289,10 +291,8 @@ func (c *Client) dialWithBalancer(dopts ...grpc.DialOption) (*grpc.ClientConn, e
 
 // dial configures and dials any grpc balancer target.
 func (c *Client) dial(creds grpccredentials.TransportCredentials, dopts ...grpc.DialOption) (*grpc.ClientConn, error) {
-	opts, err := c.dialSetupOpts(creds, dopts...)
-	if err != nil {
-		return nil, fmt.Errorf("failed to configure dialer: %v", err)
-	}
+	opts := c.dialSetupOpts(creds, dopts...)
+
 	if c.authTokenBundle != nil {
 		opts = append(opts, grpc.WithPerRPCCredentials(c.authTokenBundle.PerRPCCredentials()))
 	}

client/v3/concurrency/election.go

@@ -90,7 +90,7 @@ func (e *Election) Campaign(ctx context.Context, val string) error {
 		}
 	}
 
-	_, err = waitDeletes(ctx, client, e.keyPrefix, e.leaderRev-1)
+	err = waitDeletes(ctx, client, e.keyPrefix, e.leaderRev-1)
 	if err != nil {
 		// clean up in case of context cancel
 		select {

client/v3/concurrency/key.go

@@ -18,7 +18,6 @@ import (
 	"context"
 	"errors"
 
-	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
 	"go.etcd.io/etcd/api/v3/mvccpb"
 	v3 "go.etcd.io/etcd/client/v3"
 )
@@ -47,19 +46,19 @@ func waitDelete(ctx context.Context, client *v3.Client, key string, rev int64) e
 
 // waitDeletes efficiently waits until all keys matching the prefix and no greater
 // than the create revision are deleted.
-func waitDeletes(ctx context.Context, client *v3.Client, pfx string, maxCreateRev int64) (*pb.ResponseHeader, error) {
+func waitDeletes(ctx context.Context, client *v3.Client, pfx string, maxCreateRev int64) error {
 	getOpts := append(v3.WithLastCreate(), v3.WithMaxCreateRev(maxCreateRev))
 	for {
 		resp, err := client.Get(ctx, pfx, getOpts...)
 		if err != nil {
-			return nil, err
+			return err
 		}
 		if len(resp.Kvs) == 0 {
-			return resp.Header, nil
+			return nil
 		}
 		lastKey := string(resp.Kvs[0].Key)
 		if err = waitDelete(ctx, client, lastKey, resp.Header.Revision); err != nil {
-			return nil, err
+			return err
 		}
 	}
 }

client/v3/concurrency/mutex.go

@@ -84,7 +84,7 @@ func (m *Mutex) Lock(ctx context.Context) error {
 	client := m.s.Client()
 	// wait for deletion revisions prior to myKey
 	// TODO: early termination if the session key is deleted before other session keys with smaller revisions.
-	_, werr := waitDeletes(ctx, client, m.pfx, m.myRev-1)
+	werr := waitDeletes(ctx, client, m.pfx, m.myRev-1)
 	// release lock key if wait failed
 	if werr != nil {
 		m.Unlock(client.Ctx())

client/v3/retry.go

@@ -102,7 +102,7 @@ func RetryKVClient(c *Client) pb.KVClient {
 	}
 }
 func (rkv *retryKVClient) Range(ctx context.Context, in *pb.RangeRequest, opts ...grpc.CallOption) (resp *pb.RangeResponse, err error) {
-	return rkv.kc.Range(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rkv.kc.Range(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rkv *retryKVClient) Put(ctx context.Context, in *pb.PutRequest, opts ...grpc.CallOption) (resp *pb.PutResponse, err error) {
@@ -133,23 +133,23 @@ func RetryLeaseClient(c *Client) pb.LeaseClient {
 }
 
 func (rlc *retryLeaseClient) LeaseTimeToLive(ctx context.Context, in *pb.LeaseTimeToLiveRequest, opts ...grpc.CallOption) (resp *pb.LeaseTimeToLiveResponse, err error) {
-	return rlc.lc.LeaseTimeToLive(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rlc.lc.LeaseTimeToLive(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rlc *retryLeaseClient) LeaseLeases(ctx context.Context, in *pb.LeaseLeasesRequest, opts ...grpc.CallOption) (resp *pb.LeaseLeasesResponse, err error) {
-	return rlc.lc.LeaseLeases(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rlc.lc.LeaseLeases(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rlc *retryLeaseClient) LeaseGrant(ctx context.Context, in *pb.LeaseGrantRequest, opts ...grpc.CallOption) (resp *pb.LeaseGrantResponse, err error) {
-	return rlc.lc.LeaseGrant(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rlc.lc.LeaseGrant(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rlc *retryLeaseClient) LeaseRevoke(ctx context.Context, in *pb.LeaseRevokeRequest, opts ...grpc.CallOption) (resp *pb.LeaseRevokeResponse, err error) {
-	return rlc.lc.LeaseRevoke(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rlc.lc.LeaseRevoke(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rlc *retryLeaseClient) LeaseKeepAlive(ctx context.Context, opts ...grpc.CallOption) (stream pb.Lease_LeaseKeepAliveClient, err error) {
-	return rlc.lc.LeaseKeepAlive(ctx, append(opts, withRetryPolicy(repeatable))...)
+	return rlc.lc.LeaseKeepAlive(ctx, append(opts, withRepeatablePolicy())...)
 }
 
 type retryClusterClient struct {
@@ -164,7 +164,7 @@ func RetryClusterClient(c *Client) pb.ClusterClient {
 }
 
 func (rcc *retryClusterClient) MemberList(ctx context.Context, in *pb.MemberListRequest, opts ...grpc.CallOption) (resp *pb.MemberListResponse, err error) {
-	return rcc.cc.MemberList(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rcc.cc.MemberList(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rcc *retryClusterClient) MemberAdd(ctx context.Context, in *pb.MemberAddRequest, opts ...grpc.CallOption) (resp *pb.MemberAddResponse, err error) {
@@ -195,27 +195,27 @@ func RetryMaintenanceClient(c *Client, conn *grpc.ClientConn) pb.MaintenanceClie
 }
 
 func (rmc *retryMaintenanceClient) Alarm(ctx context.Context, in *pb.AlarmRequest, opts ...grpc.CallOption) (resp *pb.AlarmResponse, err error) {
-	return rmc.mc.Alarm(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rmc.mc.Alarm(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rmc *retryMaintenanceClient) Status(ctx context.Context, in *pb.StatusRequest, opts ...grpc.CallOption) (resp *pb.StatusResponse, err error) {
-	return rmc.mc.Status(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rmc.mc.Status(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rmc *retryMaintenanceClient) Hash(ctx context.Context, in *pb.HashRequest, opts ...grpc.CallOption) (resp *pb.HashResponse, err error) {
-	return rmc.mc.Hash(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rmc.mc.Hash(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rmc *retryMaintenanceClient) HashKV(ctx context.Context, in *pb.HashKVRequest, opts ...grpc.CallOption) (resp *pb.HashKVResponse, err error) {
-	return rmc.mc.HashKV(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rmc.mc.HashKV(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rmc *retryMaintenanceClient) Snapshot(ctx context.Context, in *pb.SnapshotRequest, opts ...grpc.CallOption) (stream pb.Maintenance_SnapshotClient, err error) {
-	return rmc.mc.Snapshot(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rmc.mc.Snapshot(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rmc *retryMaintenanceClient) MoveLeader(ctx context.Context, in *pb.MoveLeaderRequest, opts ...grpc.CallOption) (resp *pb.MoveLeaderResponse, err error) {
-	return rmc.mc.MoveLeader(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rmc.mc.MoveLeader(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rmc *retryMaintenanceClient) Defragment(ctx context.Context, in *pb.DefragmentRequest, opts ...grpc.CallOption) (resp *pb.DefragmentResponse, err error) {
@@ -238,19 +238,19 @@ func RetryAuthClient(c *Client) pb.AuthClient {
 }
 
 func (rac *retryAuthClient) UserList(ctx context.Context, in *pb.AuthUserListRequest, opts ...grpc.CallOption) (resp *pb.AuthUserListResponse, err error) {
-	return rac.ac.UserList(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rac.ac.UserList(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rac *retryAuthClient) UserGet(ctx context.Context, in *pb.AuthUserGetRequest, opts ...grpc.CallOption) (resp *pb.AuthUserGetResponse, err error) {
-	return rac.ac.UserGet(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rac.ac.UserGet(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rac *retryAuthClient) RoleGet(ctx context.Context, in *pb.AuthRoleGetRequest, opts ...grpc.CallOption) (resp *pb.AuthRoleGetResponse, err error) {
-	return rac.ac.RoleGet(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rac.ac.RoleGet(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rac *retryAuthClient) RoleList(ctx context.Context, in *pb.AuthRoleListRequest, opts ...grpc.CallOption) (resp *pb.AuthRoleListResponse, err error) {
-	return rac.ac.RoleList(ctx, in, append(opts, withRetryPolicy(repeatable))...)
+	return rac.ac.RoleList(ctx, in, append(opts, withRepeatablePolicy())...)
 }
 
 func (rac *retryAuthClient) AuthEnable(ctx context.Context, in *pb.AuthEnableRequest, opts ...grpc.CallOption) (resp *pb.AuthEnableResponse, err error) {

client/v3/retry_interceptor.go

@@ -377,10 +377,10 @@ var (
 // with the next iteration.
 type backoffFunc func(attempt uint) time.Duration
 
-// withRetryPolicy sets the retry policy of this call.
-func withRetryPolicy(rp retryPolicy) retryOption {
+// withRepeatablePolicy sets the repeatable policy of this call.
+func withRepeatablePolicy() retryOption {
 	return retryOption{applyFunc: func(o *options) {
-		o.retryPolicy = rp
+		o.retryPolicy = repeatable
 	}}
 }
 

etcdutl/etcdutl/backup_command.go

@@ -254,7 +254,7 @@ func raftEntryToNoOp(entry *raftpb.Entry) {
 }
 
 // saveDB copies the v3 backend and strips cluster information.
-func saveDB(lg *zap.Logger, destDB, srcDB string, idx uint64, term uint64, desired *desiredCluster) {
+func saveDB(lg *zap.Logger, destDB, srcDB string, _ uint64 /* idx */, _ uint64 /* term */, desired *desiredCluster) {
 	// open src db to safely copy db state
 	var src *bolt.DB
 	ch := make(chan *bolt.DB, 1)

scripts/test.sh

@@ -421,7 +421,6 @@ function govet_shadow_pass {
 }
 
 function unparam_pass {
-  # TODO: transport/listener.go:129:60: newListenConfig - result 1 (error) is always nil
   run_for_modules generic_checker run_go_tool "mvdan.cc/unparam"
 }
 

server/embed/etcd.go

@@ -269,12 +269,10 @@ func StartEtcd(inCfg *Config) (e *Etcd, err error) {
 	}
 	e.Server.Start()
 
-	if err = e.servePeers(); err != nil {
-		return e, err
-	}
-	if err = e.serveClients(); err != nil {
-		return e, err
-	}
+	e.servePeers()
+
+	e.serveClients()
+
 	if err = e.serveMetrics(); err != nil {
 		return e, err
 	}
@@ -563,7 +561,7 @@ func configurePeerListeners(cfg *Config) (peers []*peerListener, err error) {
 }
 
 // configure peer handlers after rafthttp.Transport started
-func (e *Etcd) servePeers() (err error) {
+func (e *Etcd) servePeers() {
 	ph := etcdhttp.NewPeerHandler(e.GetLogger(), e.Server)
 
 	for _, p := range e.Peers {
@@ -611,7 +609,6 @@ func (e *Etcd) servePeers() (err error) {
 			e.errHandler(l.serve())
 		}(pl)
 	}
-	return nil
 }
 
 func configureClientListeners(cfg *Config) (sctxs map[string]*serveCtx, err error) {
@@ -729,7 +726,7 @@ func resolveUrl(u url.URL) (addr string, secure bool, network string) {
 	return addr, secure, network
 }
 
-func (e *Etcd) serveClients() (err error) {
+func (e *Etcd) serveClients() {
 	if !e.cfg.ClientTLSInfo.Empty() {
 		e.cfg.logger.Info(
 			"starting with client TLS",
@@ -773,7 +770,6 @@ func (e *Etcd) serveClients() (err error) {
 			e.errHandler(s.serve(e.Server, &e.cfg.ClientTLSInfo, mux, e.errHandler, e.grpcGatewayDial(splitHttp), splitHttp, gopts...))
 		}(sctx)
 	}
-	return nil
 }
 
 func (e *Etcd) grpcGatewayDial(splitHttp bool) (grpcDial func(ctx context.Context) (*grpc.ClientConn, error)) {

server/etcdmain/grpc_proxy.go

@@ -538,8 +538,7 @@ func mustHTTPListener(lg *zap.Logger, m cmux.CMux, tlsinfo *transport.TLSInfo, c
 func mustNewHTTPClient(lg *zap.Logger) *http.Client {
 	transport, err := newHTTPTransport(grpcProxyCA, grpcProxyCert, grpcProxyKey)
 	if err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
+		lg.Fatal("failed to new http transport", zap.Error(err))
 	}
 	return &http.Client{Transport: transport}
 }

server/etcdserver/bootstrap.go

@@ -96,11 +96,7 @@ func bootstrap(cfg config.ServerConfig) (b *bootstrappedServer, err error) {
 		return nil, err
 	}
 
-	s, err := bootstrapStorage(cfg, st, backend, bwal, cluster)
-	if err != nil {
-		backend.Close()
-		return nil, err
-	}
+	s := bootstrapStorage(cfg, st, backend, bwal, cluster)
 
 	if err = cluster.Finalize(cfg, s); err != nil {
 		backend.Close()
@@ -165,7 +161,7 @@ type bootstrappedRaft struct {
 	storage *raft.MemoryStorage
 }
 
-func bootstrapStorage(cfg config.ServerConfig, st v2store.Store, be *bootstrappedBackend, wal *bootstrappedWAL, cl *bootstrapedCluster) (b *bootstrappedStorage, err error) {
+func bootstrapStorage(cfg config.ServerConfig, st v2store.Store, be *bootstrappedBackend, wal *bootstrappedWAL, cl *bootstrapedCluster) *bootstrappedStorage {
 	if wal == nil {
 		wal = bootstrapNewWAL(cfg, cl)
 	}
@@ -174,7 +170,7 @@ func bootstrapStorage(cfg config.ServerConfig, st v2store.Store, be *bootstrappe
 		backend: be,
 		st:      st,
 		wal:     wal,
-	}, nil
+	}
 }
 
 func bootstrapSnapshot(cfg config.ServerConfig) *snap.Snapshotter {