fix: enable errorlint linter

contrib/raftexample/kvstore.go

@@ -18,6 +18,7 @@ import (
 	"bytes"
 	"encoding/gob"
 	"encoding/json"
+	"errors"
 	"log"
 	"strings"
 	"sync"
@@ -113,7 +114,7 @@ func (s *kvstore) getSnapshot() ([]byte, error) {
 
 func (s *kvstore) loadSnapshot() (*raftpb.Snapshot, error) {
 	snapshot, err := s.snapshotter.Load()
-	if err == snap.ErrNoSnapshot {
+	if errors.Is(err, snap.ErrNoSnapshot) {
 		return nil, nil
 	}
 	if err != nil {

contrib/raftexample/raft.go

@@ -16,6 +16,7 @@ package main
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"log"
 	"net/http"
@@ -206,7 +207,7 @@ func (rc *raftNode) loadSnapshot() *raftpb.Snapshot {
 			log.Fatalf("raftexample: error listing snapshots (%v)", err)
 		}
 		snapshot, err := rc.snapshotter.LoadNewestAvailable(walSnaps)
-		if err != nil && err != snap.ErrNoSnapshot {
+		if err != nil && !errors.Is(err, snap.ErrNoSnapshot) {
 			log.Fatalf("raftexample: error loading snapshot (%v)", err)
 		}
 		return snapshot
@@ -391,7 +392,7 @@ func (rc *raftNode) maybeTriggerSnapshot(applyDoneC <-chan struct{}) {
 		compactIndex = rc.appliedIndex - snapshotCatchUpEntriesN
 	}
 	if err := rc.raftStorage.Compact(compactIndex); err != nil {
-		if err != raft.ErrCompacted {
+		if !errors.Is(err, raft.ErrCompacted) {
 			panic(err)
 		}
 	} else {

tests/e2e/ctl_v3_auth_test.go

@@ -46,13 +46,13 @@ func TestCtlV3AuthSnapshotJWT(t *testing.T) {
 func authEnable(cx ctlCtx) error {
 	// create root user with root role
 	if err := ctlV3User(cx, []string{"add", "root", "--interactive=false"}, "User root created", []string{"root"}); err != nil {
-		return fmt.Errorf("failed to create root user %v", err)
+		return fmt.Errorf("failed to create root user %w", err)
 	}
 	if err := ctlV3User(cx, []string{"grant-role", "root", "root"}, "Role root is granted to user root", nil); err != nil {
-		return fmt.Errorf("failed to grant root user root role %v", err)
+		return fmt.Errorf("failed to grant root user root role %w", err)
 	}
 	if err := ctlV3AuthEnable(cx); err != nil {
-		return fmt.Errorf("authEnableTest ctlV3AuthEnable error (%v)", err)
+		return fmt.Errorf("authEnableTest ctlV3AuthEnable error (%w)", err)
 	}
 	return nil
 }

tests/e2e/utils.go

@@ -77,7 +77,7 @@ func tlsInfo(t testing.TB, cfg e2e.ClientConfig) (*transport.TLSInfo, error) {
 		if cfg.AutoTLS {
 			tls, err := transport.SelfCert(zap.NewNop(), t.TempDir(), []string{"localhost"}, 1)
 			if err != nil {
-				return nil, fmt.Errorf("failed to generate cert: %s", err)
+				return nil, fmt.Errorf("failed to generate cert: %w", err)
 			}
 			return &tls, nil
 		}

tests/e2e/v3_curl_election_test.go

@@ -173,7 +173,7 @@ func CURLWithExpected(cx ctlCtx, tests []v3cURLTest) error {
 	for _, t := range tests {
 		value := fmt.Sprintf("%v", t.value)
 		if err := e2e.CURLPost(cx.epc, e2e.CURLReq{Endpoint: t.endpoint, Value: value, Expected: expect.ExpectedResponse{Value: t.expected}}); err != nil {
-			return fmt.Errorf("endpoint (%s): error (%v), wanted %v", t.endpoint, err, t.expected)
+			return fmt.Errorf("endpoint (%s): error (%w), wanted %v", t.endpoint, err, t.expected)
 		}
 	}
 	return nil

tests/e2e/v3_curl_maxstream_test.go

@@ -169,7 +169,7 @@ func submitConcurrentWatch(cx ctlCtx, number int, wgDone *sync.WaitGroup, closeC
 		expectedLine := `"created":true}}`
 		_, lerr := proc.ExpectWithContext(context.TODO(), expect.ExpectedResponse{Value: expectedLine})
 		if lerr != nil {
-			return fmt.Errorf("%v %v (expected %q). Try EXPECT_DEBUG=TRUE", args, lerr, expectedLine)
+			return fmt.Errorf("%v %w (expected %q). Try EXPECT_DEBUG=TRUE", args, lerr, expectedLine)
 		}
 
 		wgSchedule.Done()
@@ -182,7 +182,7 @@ func submitConcurrentWatch(cx ctlCtx, number int, wgDone *sync.WaitGroup, closeC
 		case <-closeCh:
 		default:
 			// perr could be nil.
-			return fmt.Errorf("unexpected connection close before server closes: %v", perr)
+			return fmt.Errorf("unexpected connection close before server closes: %w", perr)
 		}
 		return nil
 	}
@@ -225,19 +225,19 @@ func submitRangeAfterConcurrentWatch(cx ctlCtx, expectedValue string) {
 func setRLimit(nofile uint64) (func() error, error) {
 	var rLimit syscall.Rlimit
 	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rLimit); err != nil {
-		return nil, fmt.Errorf("failed to get open file limit, error: %v", err)
+		return nil, fmt.Errorf("failed to get open file limit, error: %w", err)
 	}
 
 	var wLimit syscall.Rlimit
 	wLimit.Max = nofile
 	wLimit.Cur = nofile
 	if err := syscall.Setrlimit(syscall.RLIMIT_NOFILE, &wLimit); err != nil {
-		return nil, fmt.Errorf("failed to set max open file limit, %v", err)
+		return nil, fmt.Errorf("failed to set max open file limit, %w", err)
 	}
 
 	return func() error {
 		if err := syscall.Setrlimit(syscall.RLIMIT_NOFILE, &rLimit); err != nil {
-			return fmt.Errorf("failed reset max open file limit, %v", err)
+			return fmt.Errorf("failed reset max open file limit, %w", err)
 		}
 		return nil
 	}, nil

tests/framework/e2e/cluster.go

@@ -437,7 +437,7 @@ func InitEtcdProcessCluster(t testing.TB, cfg *EtcdProcessClusterConfig) (*EtcdP
 		proc, err := NewEtcdProcess(t, etcdCfgs[i])
 		if err != nil {
 			epc.Close()
-			return nil, fmt.Errorf("cannot configure: %v", err)
+			return nil, fmt.Errorf("cannot configure: %w", err)
 		}
 		epc.Procs[i] = proc
 	}
@@ -449,11 +449,11 @@ func InitEtcdProcessCluster(t testing.TB, cfg *EtcdProcessClusterConfig) (*EtcdP
 func StartEtcdProcessCluster(ctx context.Context, t testing.TB, epc *EtcdProcessCluster, cfg *EtcdProcessClusterConfig) (*EtcdProcessCluster, error) {
 	if cfg.RollingStart {
 		if err := epc.RollingStart(ctx); err != nil {
-			return nil, fmt.Errorf("cannot rolling-start: %v", err)
+			return nil, fmt.Errorf("cannot rolling-start: %w", err)
 		}
 	} else {
 		if err := epc.Start(ctx); err != nil {
-			return nil, fmt.Errorf("cannot start: %v", err)
+			return nil, fmt.Errorf("cannot start: %w", err)
 		}
 	}
 
@@ -465,7 +465,7 @@ func StartEtcdProcessCluster(ctx context.Context, t testing.TB, epc *EtcdProcess
 	}
 	if cfg.InitialLeaderIndex >= 0 {
 		if err := epc.MoveLeader(ctx, t, cfg.InitialLeaderIndex); err != nil {
-			return nil, fmt.Errorf("failed to move leader: %v", err)
+			return nil, fmt.Errorf("failed to move leader: %w", err)
 		}
 	}
 	return epc, nil
@@ -864,7 +864,7 @@ func (epc *EtcdProcessCluster) StartNewProcFromConfig(ctx context.Context, tb te
 	proc, err := NewEtcdProcess(tb, serverCfg)
 	if err != nil {
 		epc.Close()
-		return fmt.Errorf("cannot configure: %v", err)
+		return fmt.Errorf("cannot configure: %w", err)
 	}
 
 	epc.Procs = append(epc.Procs, proc)
@@ -947,7 +947,7 @@ func (epc *EtcdProcessCluster) Stop() (err error) {
 		}
 		if curErr := p.Stop(); curErr != nil {
 			if err != nil {
-				err = fmt.Errorf("%v; %v", err, curErr)
+				err = fmt.Errorf("%w; %w", err, curErr)
 			} else {
 				err = curErr
 			}
@@ -969,7 +969,7 @@ func (epc *EtcdProcessCluster) ConcurrentStop() (err error) {
 	for range epc.Procs {
 		if curErr := <-errCh; curErr != nil {
 			if err != nil {
-				err = fmt.Errorf("%v; %v", err, curErr)
+				err = fmt.Errorf("%w; %w", err, curErr)
 			} else {
 				err = curErr
 			}

tests/framework/e2e/etcdctl.go

@@ -17,6 +17,7 @@ package e2e
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"strconv"
@@ -252,7 +253,7 @@ func AddTxnResponse(resp *clientv3.TxnResponse, jsonData string) {
 	jd := json.NewDecoder(strings.NewReader(jsonData))
 	for {
 		t, e := jd.Token()
-		if e == io.EOF {
+		if errors.Is(e, io.EOF) {
 			break
 		}
 		if t == "response_range" {

tests/framework/e2e/util.go

@@ -73,7 +73,7 @@ func SpawnWithExpectLines(ctx context.Context, args []string, envVars map[string
 		l, lerr := proc.ExpectWithContext(ctx, txt)
 		if lerr != nil {
 			proc.Close()
-			return nil, fmt.Errorf("%v %v (expected %q, got %q). Try EXPECT_DEBUG=TRUE", args, lerr, txt.Value, lines)
+			return nil, fmt.Errorf("%v %w (expected %q, got %q). Try EXPECT_DEBUG=TRUE", args, lerr, txt.Value, lines)
 		}
 		lines = append(lines, l)
 	}

tests/framework/integration/cluster.go

@@ -780,13 +780,13 @@ func (m *Member) listenGRPC() error {
 	m.Logger.Info("LISTEN GRPC", zap.String("grpcAddr", grpcAddr), zap.String("m.Name", m.Name), zap.String("workdir", wd))
 	grpcListener, err := net.Listen(network, grpcAddr)
 	if err != nil {
-		return fmt.Errorf("listen failed on grpc socket %s (%v)", grpcAddr, err)
+		return fmt.Errorf("listen failed on grpc socket %s (%w)", grpcAddr, err)
 	}
 
 	addr := grpcListener.Addr().String()
 	_, port, err = net.SplitHostPort(addr)
 	if err != nil {
-		return fmt.Errorf("failed to parse grpc listen port from address %s (%v)", addr, err)
+		return fmt.Errorf("failed to parse grpc listen port from address %s (%w)", addr, err)
 	}
 	m.Port = port
 	m.GRPCURL = fmt.Sprintf("%s://%s", m.clientScheme(), addr)
@@ -830,7 +830,7 @@ func (m *Member) addBridge() (*bridge, error) {
 	m.Logger.Info("LISTEN BRIDGE", zap.String("grpc-address", bridgeAddr), zap.String("member", m.Name))
 	bridgeListener, err := transport.NewUnixListener(bridgeAddr)
 	if err != nil {
-		return nil, fmt.Errorf("listen failed on bridge socket %s (%v)", bridgeAddr, err)
+		return nil, fmt.Errorf("listen failed on bridge socket %s (%w)", bridgeAddr, err)
 	}
 	m.GRPCBridge = newBridge(dialer{network: network, addr: grpcAddr}, bridgeListener)
 
@@ -962,7 +962,7 @@ func (m *Member) Launch() error {
 	)
 	var err error
 	if m.Server, err = etcdserver.NewServer(m.ServerConfig); err != nil {
-		return fmt.Errorf("failed to initialize the etcd server: %v", err)
+		return fmt.Errorf("failed to initialize the etcd server: %w", err)
 	}
 	m.Server.SyncTicker = time.NewTicker(500 * time.Millisecond)
 	m.Server.Start()
@@ -1568,7 +1568,7 @@ func (c *Cluster) GetLearnerMembers() ([]*pb.Member, error) {
 	cli := c.Client(0)
 	resp, err := cli.MemberList(context.Background())
 	if err != nil {
-		return nil, fmt.Errorf("failed to list member %v", err)
+		return nil, fmt.Errorf("failed to list member %w", err)
 	}
 	var learners []*pb.Member
 	for _, m := range resp.Members {

tests/framework/integration/integration.go

@@ -77,7 +77,7 @@ func tlsInfo(t testing.TB, cfg config.TLSConfig) (*transport.TLSInfo, error) {
 	case config.AutoTLS:
 		tls, err := transport.SelfCert(zap.NewNop(), t.TempDir(), []string{"localhost"}, 1)
 		if err != nil {
-			return nil, fmt.Errorf("failed to generate cert: %s", err)
+			return nil, fmt.Errorf("failed to generate cert: %w", err)
 		}
 		return &tls, nil
 	case config.ManualTLS:

tests/integration/clientv3/kv_test.go

@@ -461,7 +461,7 @@ func TestKVCompact(t *testing.T) {
 	if !wr.Canceled {
 		t.Fatalf("expected canceled watcher on compacted revision, got %v", wr.Canceled)
 	}
-	if wr.Err() != rpctypes.ErrCompacted {
+	if !errors.Is(wr.Err(), rpctypes.ErrCompacted) {
 		t.Fatalf("watch response error expected %v, got %v", rpctypes.ErrCompacted, wr.Err())
 	}
 	wr, ok := <-wchan
@@ -750,7 +750,8 @@ func TestKVLargeRequests(t *testing.T) {
 		cli := clus.Client(0)
 		_, err := cli.Put(context.TODO(), "foo", strings.Repeat("a", test.valueSize))
 
-		if _, ok := err.(rpctypes.EtcdError); ok {
+		var etcdErr rpctypes.EtcdError
+		if errors.As(err, &etcdErr) {
 			if !errors.Is(err, test.expectError) {
 				t.Errorf("#%d: expected %v, got %v", i, test.expectError, err)
 			}

tests/integration/clientv3/lease/lease_test.go

@@ -721,7 +721,8 @@ func TestLeaseKeepAliveLoopExit(t *testing.T) {
 	cli.Close()
 
 	_, err = cli.KeepAlive(ctx, resp.ID)
-	if _, ok := err.(clientv3.ErrKeepAliveHalted); !ok {
+	var keepAliveHaltedErr clientv3.ErrKeepAliveHalted
+	if !errors.As(err, &keepAliveHaltedErr) {
 		t.Fatalf("expected %T, got %v(%T)", clientv3.ErrKeepAliveHalted{}, err, err)
 	}
 }

tests/integration/clientv3/user_test.go

@@ -194,10 +194,10 @@ func TestGetTokenWithoutAuth(t *testing.T) {
 		defer client.Close()
 	}
 
-	switch err {
-	case nil:
+	switch {
+	case err == nil:
 		t.Log("passes as expected")
-	case context.DeadlineExceeded:
+	case errors.Is(err, context.DeadlineExceeded):
 		t.Errorf("not expected result:%v with endpoint:%s", err, authapi.Endpoints())
 	default:
 		t.Errorf("other errors:%v", err)

tests/integration/clientv3/watch_test.go

@@ -472,7 +472,7 @@ func TestWatchResumeCompacted(t *testing.T) {
 		if wresp.Err() == nil {
 			continue
 		}
-		if wresp.Err() != rpctypes.ErrCompacted {
+		if !errors.Is(wresp.Err(), rpctypes.ErrCompacted) {
 			t.Fatalf("wresp.Err() expected %v, got %+v", rpctypes.ErrCompacted, wresp.Err())
 		}
 		break
@@ -519,7 +519,7 @@ func TestWatchCompactRevision(t *testing.T) {
 	if !ok {
 		t.Fatalf("expected wresp, but got closed channel")
 	}
-	if wresp.Err() != rpctypes.ErrCompacted {
+	if !errors.Is(wresp.Err(), rpctypes.ErrCompacted) {
 		t.Fatalf("wresp.Err() expected %v, but got %v", rpctypes.ErrCompacted, wresp.Err())
 	}
 	if !wresp.Canceled {
@@ -858,7 +858,7 @@ func TestWatchWithRequireLeader(t *testing.T) {
 		if !ok {
 			t.Fatalf("expected %v watch channel, got closed channel", rpctypes.ErrNoLeader)
 		}
-		if resp.Err() != rpctypes.ErrNoLeader {
+		if !errors.Is(resp.Err(), rpctypes.ErrNoLeader) {
 			t.Fatalf("expected %v watch response error, got %+v", rpctypes.ErrNoLeader, resp)
 		}
 	case <-time.After(integration2.RequestWaitTimeout):