Use atomic pointer in go 1.19 (#446)

* use atomic pointer

* golang version

* golang version

* go1.19

* linters

* Bump golangci-lint

* linters

* linters

* linters after merge

* generic logger

* generic logger

* logger

* logger

* linters

* bump toml

* linters1

* linters

* linters

* linter

* linter

* linters

* linters

* linters

.github/workflows/ci.yml

@@ -29,7 +29,7 @@ jobs:
 
         - uses: actions/setup-go@v3
           with:
-            go-version: 1.18.x
+            go-version: 1.19.x
 
         - name: Install dependencies on Linux
           if: runner.os == 'Linux'

.golangci.yml

@@ -50,6 +50,7 @@ linters:
     - unconvert
     - unparam
     - wsl
+    - asasalint
     #- errorlint causes stack overflow. TODO: recheck after each golangci update
 
 linters-settings:

Makefile

@@ -75,7 +75,7 @@ lint:
 
 lintci-deps:
 	rm -f ./build/bin/golangci-lint
-	curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b ./build/bin v1.46.0
+	curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b ./build/bin v1.48.0
 
 goimports:
 	goimports -local "$(PACKAGE)" -w .

accounts/abi/bind/auth.go

@@ -21,7 +21,6 @@ import (
 	"crypto/ecdsa"
 	"errors"
 	"io"
-	"io/ioutil"
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/accounts"
@@ -45,14 +44,17 @@ var ErrNotAuthorized = errors.New("not authorized to sign this account")
 // Deprecated: Use NewTransactorWithChainID instead.
 func NewTransactor(keyin io.Reader, passphrase string) (*TransactOpts, error) {
 	log.Warn("WARNING: NewTransactor has been deprecated in favour of NewTransactorWithChainID")
-	json, err := ioutil.ReadAll(keyin)
+
+	json, err := io.ReadAll(keyin)
 	if err != nil {
 		return nil, err
 	}
+
 	key, err := keystore.DecryptKey(json, passphrase)
 	if err != nil {
 		return nil, err
 	}
+
 	return NewKeyedTransactor(key.PrivateKey), nil
 }
 
@@ -106,7 +108,7 @@ func NewKeyedTransactor(key *ecdsa.PrivateKey) *TransactOpts {
 // NewTransactorWithChainID is a utility method to easily create a transaction signer from
 // an encrypted json key stream and the associated passphrase.
 func NewTransactorWithChainID(keyin io.Reader, passphrase string, chainID *big.Int) (*TransactOpts, error) {
-	json, err := ioutil.ReadAll(keyin)
+	json, err := io.ReadAll(keyin)
 	if err != nil {
 		return nil, err
 	}

accounts/abi/bind/bind_test.go

@@ -18,7 +18,6 @@ package bind
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -1966,7 +1965,7 @@ func TestGolangBindings(t *testing.T) {
 		t.Skip("go sdk not found for testing")
 	}
 	// Create a temporary workspace for the test suite
-	ws, err := ioutil.TempDir("", "binding-test")
+	ws, err := os.MkdirTemp("", "binding-test")
 	if err != nil {
 		t.Fatalf("failed to create temporary workspace: %v", err)
 	}
@@ -1990,7 +1989,7 @@ func TestGolangBindings(t *testing.T) {
 			if err != nil {
 				t.Fatalf("test %d: failed to generate binding: %v", i, err)
 			}
-			if err = ioutil.WriteFile(filepath.Join(pkg, strings.ToLower(tt.name)+".go"), []byte(bind), 0600); err != nil {
+			if err = os.WriteFile(filepath.Join(pkg, strings.ToLower(tt.name)+".go"), []byte(bind), 0600); err != nil {
 				t.Fatalf("test %d: failed to write binding: %v", i, err)
 			}
 			// Generate the test file with the injected test code
@@ -2006,7 +2005,7 @@ func TestGolangBindings(t *testing.T) {
 				%s
 			}
 		`, tt.imports, tt.name, tt.tester)
-			if err := ioutil.WriteFile(filepath.Join(pkg, strings.ToLower(tt.name)+"_test.go"), []byte(code), 0600); err != nil {
+			if err := os.WriteFile(filepath.Join(pkg, strings.ToLower(tt.name)+"_test.go"), []byte(code), 0600); err != nil {
 				t.Fatalf("test %d: failed to write tests: %v", i, err)
 			}
 		})

cmd/geth/config.go

@@ -18,14 +18,12 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
 	"math/big"
 	"os"
 	"time"
 
-	"gopkg.in/urfave/cli.v1"
-
 	"github.com/BurntSushi/toml"
+	"gopkg.in/urfave/cli.v1"
 
 	"github.com/ethereum/go-ethereum/accounts/external"
 	"github.com/ethereum/go-ethereum/accounts/keystore"
@@ -71,7 +69,7 @@ type gethConfig struct {
 }
 
 func loadConfig(file string, cfg *gethConfig) error {
-	data, err := ioutil.ReadFile(file)
+	data, err := os.ReadFile(file)
 	if err != nil {
 		return err
 	}

consensus/bor/bor.go

@@ -12,6 +12,7 @@ import (
 	"sort"
 	"strconv"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	lru "github.com/hashicorp/golang-lru"
@@ -97,6 +98,9 @@ var (
 	// errOutOfRangeChain is returned if an authorization list is attempted to
 	// be modified via out-of-range or non-contiguous headers.
 	errOutOfRangeChain = errors.New("out of range or non-contiguous chain")
+
+	errUncleDetected     = errors.New("uncles not allowed")
+	errUnknownValidators = errors.New("unknown validators")
 )
 
 // SignerFn is a signer callback function to request a header to be signed by a
@@ -210,9 +214,7 @@ type Bor struct {
 	recents    *lru.ARCCache // Snapshots for recent block to speed up reorgs
 	signatures *lru.ARCCache // Signatures of recent blocks to speed up mining
 
-	signer common.Address // Ethereum address of the signing key
-	signFn SignerFn       // Signer function to authorize hashes with
-	lock   sync.RWMutex   // Protects the signer fields
+	authorizedSigner atomic.Pointer[signer] // Ethereum address and sign function of the signing key
 
 	ethAPI                 api.Caller
 	spanner                Spanner
@@ -225,6 +227,11 @@ type Bor struct {
 	closeOnce sync.Once
 }
 
+type signer struct {
+	signer common.Address // Ethereum address of the signing key
+	signFn SignerFn       // Signer function to authorize hashes with
+}
+
 // New creates a Matic Bor consensus engine.
 func New(
 	chainConfig *params.ChainConfig,
@@ -257,6 +264,14 @@ func New(
 		HeimdallClient:         heimdallClient,
 	}
 
+	c.authorizedSigner.Store(&signer{
+		common.Address{},
+		func(_ accounts.Account, _ string, i []byte) ([]byte, error) {
+			// return an error to prevent panics
+			return nil, &UnauthorizedSignerError{0, common.Address{}.Bytes()}
+		},
+	})
+
 	// make sure we can decode all the GenesisAlloc in the BorConfig.
 	for key, genesisAlloc := range c.config.BlockAlloc {
 		if _, err := decodeGenesisAlloc(genesisAlloc); err != nil {
@@ -572,7 +587,7 @@ func (c *Bor) snapshot(chain consensus.ChainHeaderReader, number uint64, hash co
 // uncles as this consensus mechanism doesn't permit uncles.
 func (c *Bor) VerifyUncles(_ consensus.ChainReader, block *types.Block) error {
 	if len(block.Uncles()) > 0 {
-		return errors.New("uncles not allowed")
+		return errUncleDetected
 	}
 
 	return nil
@@ -656,8 +671,10 @@ func (c *Bor) Prepare(chain consensus.ChainHeaderReader, header *types.Header) e
 		return err
 	}
 
+	currentSigner := *c.authorizedSigner.Load()
+
 	// Set the correct difficulty
-	header.Difficulty = new(big.Int).SetUint64(Difficulty(snap.ValidatorSet, c.signer))
+	header.Difficulty = new(big.Int).SetUint64(Difficulty(snap.ValidatorSet, currentSigner.signer))
 
 	// Ensure the extra data has all it's components
 	if len(header.Extra) < extraVanity {
@@ -670,7 +687,7 @@ func (c *Bor) Prepare(chain consensus.ChainHeaderReader, header *types.Header) e
 	if IsSprintStart(number+1, c.config.Sprint) {
 		newValidators, err := c.spanner.GetCurrentValidators(context.Background(), header.ParentHash, number+1)
 		if err != nil {
-			return errors.New("unknown validators")
+			return errUnknownValidators
 		}
 
 		// sort validator by address
@@ -695,8 +712,8 @@ func (c *Bor) Prepare(chain consensus.ChainHeaderReader, header *types.Header) e
 
 	var succession int
 	// if signer is not empty
-	if c.signer != (common.Address{}) {
-		succession, err = snap.GetSignerSuccessionNumber(c.signer)
+	if currentSigner.signer != (common.Address{}) {
+		succession, err = snap.GetSignerSuccessionNumber(currentSigner.signer)
 		if err != nil {
 			return err
 		}
@@ -774,7 +791,7 @@ func (c *Bor) changeContractCodeIfNeeded(headerNumber uint64, state *state.State
 		if blockNumber == strconv.FormatUint(headerNumber, 10) {
 			allocs, err := decodeGenesisAlloc(genesisAlloc)
 			if err != nil {
-				return fmt.Errorf("failed to decode genesis alloc: %v", err)
+				return fmt.Errorf("failed to decode genesis alloc: %w", err)
 			}
 
 			for addr, account := range allocs {
@@ -838,12 +855,11 @@ func (c *Bor) FinalizeAndAssemble(chain consensus.ChainHeaderReader, header *typ
 
 // Authorize injects a private key into the consensus engine to mint new blocks
 // with.
-func (c *Bor) Authorize(signer common.Address, signFn SignerFn) {
-	c.lock.Lock()
-	defer c.lock.Unlock()
-
-	c.signer = signer
-	c.signFn = signFn
+func (c *Bor) Authorize(currentSigner common.Address, signFn SignerFn) {
+	c.authorizedSigner.Store(&signer{
+		signer: currentSigner,
+		signFn: signFn,
+	})
 }
 
 // Seal implements consensus.Engine, attempting to create a sealed block using
@@ -860,10 +876,9 @@ func (c *Bor) Seal(chain consensus.ChainHeaderReader, block *types.Block, result
 		log.Info("Sealing paused, waiting for transactions")
 		return nil
 	}
+
 	// Don't hold the signer fields for the entire sealing procedure
-	c.lock.RLock()
-	signer, signFn := c.signer, c.signFn
-	c.lock.RUnlock()
+	currentSigner := *c.authorizedSigner.Load()
 
 	snap, err := c.snapshot(chain, number-1, header.ParentHash, nil)
 	if err != nil {
@@ -871,12 +886,12 @@ func (c *Bor) Seal(chain consensus.ChainHeaderReader, block *types.Block, result
 	}
 
 	// Bail out if we're unauthorized to sign a block
-	if !snap.ValidatorSet.HasAddress(signer) {
+	if !snap.ValidatorSet.HasAddress(currentSigner.signer) {
 		// Check the UnauthorizedSignerError.Error() msg to see why we pass number-1
-		return &UnauthorizedSignerError{number - 1, signer.Bytes()}
+		return &UnauthorizedSignerError{number - 1, currentSigner.signer.Bytes()}
 	}
 
-	successionNumber, err := snap.GetSignerSuccessionNumber(signer)
+	successionNumber, err := snap.GetSignerSuccessionNumber(currentSigner.signer)
 	if err != nil {
 		return err
 	}
@@ -887,7 +902,7 @@ func (c *Bor) Seal(chain consensus.ChainHeaderReader, block *types.Block, result
 	wiggle := time.Duration(successionNumber) * time.Duration(c.config.CalculateBackupMultiplier(number)) * time.Second
 
 	// Sign all the things!
-	err = Sign(signFn, signer, header, c.config)
+	err = Sign(currentSigner.signFn, currentSigner.signer, header, c.config)
 	if err != nil {
 		return err
 	}
@@ -949,7 +964,7 @@ func (c *Bor) CalcDifficulty(chain consensus.ChainHeaderReader, _ uint64, parent
 		return nil
 	}
 
-	return new(big.Int).SetUint64(Difficulty(snap.ValidatorSet, c.signer))
+	return new(big.Int).SetUint64(Difficulty(snap.ValidatorSet, c.authorizedSigner.Load().signer))
 }
 
 // SealHash returns the hash of a block prior to it being sealed.

consensus/bor/heimdallgrpc/state_sync.go

@@ -3,10 +3,10 @@ package heimdallgrpc
 import (
 	"context"
 
+	proto "github.com/maticnetwork/polyproto/heimdall"
+
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/consensus/bor/clerk"
-
-	proto "github.com/maticnetwork/polyproto/heimdall"
 )
 
 func (h *HeimdallGRPCClient) StateSyncEvents(ctx context.Context, fromID uint64, to int64) ([]*clerk.EventRecordWithTime, error) {
@@ -18,13 +18,19 @@ func (h *HeimdallGRPCClient) StateSyncEvents(ctx context.Context, fromID uint64,
 		Limit:  uint64(stateFetchLimit),
 	}
 
-	res, err := h.client.StateSyncEvents(ctx, req)
+	var (
+		res    proto.Heimdall_StateSyncEventsClient
+		events *proto.StateSyncEventsResponse
+		err    error
+	)
+
+	res, err = h.client.StateSyncEvents(ctx, req)
 	if err != nil {
 		return nil, err
 	}
 
 	for {
-		events, err := res.Recv()
+		events, err = res.Recv()
 		if err != nil {
 			break
 		}
@@ -45,5 +51,5 @@ func (h *HeimdallGRPCClient) StateSyncEvents(ctx context.Context, fromID uint64,
 		}
 	}
 
-	return eventRecords, nil
+	return eventRecords, err
 }

eth/downloader/downloader.go

@@ -207,7 +207,7 @@ type BlockChain interface {
 }
 
 // New creates a new downloader to fetch hashes and blocks from remote peers.
-//nolint: staticcheck
+// nolint: staticcheck
 func New(checkpoint uint64, stateDb ethdb.Database, mux *event.TypeMux, chain BlockChain, lightchain LightChain, dropPeer peerDropFn, success func(), whitelistService ethereum.ChainValidator) *Downloader {
 	if lightchain == nil {
 		lightchain = chain
@@ -729,9 +729,11 @@ func (d *Downloader) fetchHead(p *peerConnection) (head *types.Header, pivot *ty
 // calculateRequestSpan calculates what headers to request from a peer when trying to determine the
 // common ancestor.
 // It returns parameters to be used for peer.RequestHeadersByNumber:
-//  from - starting block number
-//  count - number of headers to request
-//  skip - number of headers to skip
+//
+//	from - starting block number
+//	count - number of headers to request
+//	skip - number of headers to skip
+//
 // and also returns 'max', the last block which is expected to be returned by the remote peers,
 // given the (from,count,skip)
 func calculateRequestSpan(remoteHeight, localHeight uint64) (int64, int, int, uint64) {

eth/filters/test_backend.go

@@ -48,7 +48,11 @@ func (b *TestBackend) GetBorBlockReceipt(ctx context.Context, hash common.Hash)
 
 func (b *TestBackend) GetBorBlockLogs(ctx context.Context, hash common.Hash) ([]*types.Log, error) {
 	receipt, err := b.GetBorBlockReceipt(ctx, hash)
-	if receipt == nil || err != nil {
+	if err != nil {
+		return []*types.Log{}, err
+	}
+
+	if receipt == nil {
 		return []*types.Log{}, nil
 	}
 

go.mod

@@ -1,6 +1,6 @@
 module github.com/ethereum/go-ethereum
 
-go 1.18
+go 1.19
 
 require (
 	github.com/Azure/azure-sdk-for-go/sdk/storage/azblob v0.3.0

internal/cli/server/config_legacy.go

@@ -2,13 +2,13 @@ package server
 
 import (
 	"fmt"
-	"io/ioutil"
+	"os"
 
 	"github.com/BurntSushi/toml"
 )
 
 func readLegacyConfig(path string) (*Config, error) {
-	data, err := ioutil.ReadFile(path)
+	data, err := os.ReadFile(path)
 	tomlData := string(data)
 
 	if err != nil {

internal/testlog/testlog.go

@@ -26,12 +26,13 @@ import (
 
 // Handler returns a log handler which logs to the unit test log of t.
 func Handler(t *testing.T, level log.Lvl) log.Handler {
-	return log.LvlFilterHandler(level, &handler{t, log.TerminalFormat(false)})
+	return log.LvlFilterHandler(level, &handler{t, log.TerminalFormat(false), level})
 }
 
 type handler struct {
 	t   *testing.T
 	fmt log.Format
+	lvl log.Lvl
 }
 
 func (h *handler) Log(r *log.Record) error {
@@ -39,6 +40,10 @@ func (h *handler) Log(r *log.Record) error {
 	return nil
 }
 
+func (h *handler) Level() log.Lvl {
+	return h.lvl
+}
+
 // logger implements log.Logger such that all output goes to the unit test log via
 // t.Logf(). All methods in between logger.Trace, logger.Debug, etc. are marked as test
 // helpers, so the file and line number in unit test output correspond to the call site
@@ -59,6 +64,9 @@ func (h *bufHandler) Log(r *log.Record) error {
 	h.buf = append(h.buf, r)
 	return nil
 }
+func (h *bufHandler) Level() log.Lvl {
+	return log.LvlTrace
+}
 
 // Logger returns a logger which logs to the unit test log of t.
 func Logger(t *testing.T, level log.Lvl) log.Logger {

log/handler.go

@@ -17,18 +17,26 @@ import (
 // them to achieve the logging structure that suits your applications.
 type Handler interface {
 	Log(r *Record) error
+	Level() Lvl
 }
 
 // FuncHandler returns a Handler that logs records with the given
 // function.
-func FuncHandler(fn func(r *Record) error) Handler {
-	return funcHandler(fn)
+func FuncHandler(fn func(r *Record) error, lvl Lvl) Handler {
+	return funcHandler{fn, lvl}
 }
 
-type funcHandler func(r *Record) error
+type funcHandler struct {
+	log func(r *Record) error
+	lvl Lvl
+}
 
 func (h funcHandler) Log(r *Record) error {
-	return h(r)
+	return h.log(r)
+}
+
+func (h funcHandler) Level() Lvl {
+	return h.lvl
 }
 
 // StreamHandler writes log records to an io.Writer
@@ -42,7 +50,7 @@ func StreamHandler(wr io.Writer, fmtr Format) Handler {
 	h := FuncHandler(func(r *Record) error {
 		_, err := wr.Write(fmtr.Format(r))
 		return err
-	})
+	}, LvlTrace)
 	return LazyHandler(SyncHandler(h))
 }
 
@@ -55,7 +63,7 @@ func SyncHandler(h Handler) Handler {
 		defer mu.Unlock()
 		mu.Lock()
 		return h.Log(r)
-	})
+	}, h.Level())
 }
 
 // FileHandler returns a handler which writes log records to the give file
@@ -99,7 +107,7 @@ func CallerFileHandler(h Handler) Handler {
 	return FuncHandler(func(r *Record) error {
 		r.Ctx = append(r.Ctx, "caller", fmt.Sprint(r.Call))
 		return h.Log(r)
-	})
+	}, h.Level())
 }
 
 // CallerFuncHandler returns a Handler that adds the calling function name to
@@ -108,7 +116,7 @@ func CallerFuncHandler(h Handler) Handler {
 	return FuncHandler(func(r *Record) error {
 		r.Ctx = append(r.Ctx, "fn", formatCall("%+n", r.Call))
 		return h.Log(r)
-	})
+	}, h.Level())
 }
 
 // This function is here to please go vet on Go < 1.8.
@@ -128,29 +136,28 @@ func CallerStackHandler(format string, h Handler) Handler {
 			r.Ctx = append(r.Ctx, "stack", fmt.Sprintf(format, s))
 		}
 		return h.Log(r)
-	})
+	}, h.Level())
 }
 
 // FilterHandler returns a Handler that only writes records to the
 // wrapped Handler if the given function evaluates true. For example,
 // to only log records where the 'err' key is not nil:
 //
-//    logger.SetHandler(FilterHandler(func(r *Record) bool {
-//        for i := 0; i < len(r.Ctx); i += 2 {
-//            if r.Ctx[i] == "err" {
-//                return r.Ctx[i+1] != nil
-//            }
-//        }
-//        return false
-//    }, h))
-//
+//	logger.SetHandler(FilterHandler(func(r *Record) bool {
+//	    for i := 0; i < len(r.Ctx); i += 2 {
+//	        if r.Ctx[i] == "err" {
+//	            return r.Ctx[i+1] != nil
+//	        }
+//	    }
+//	    return false
+//	}, h))
 func FilterHandler(fn func(r *Record) bool, h Handler) Handler {
 	return FuncHandler(func(r *Record) error {
 		if fn(r) {
 			return h.Log(r)
 		}
 		return nil
-	})
+	}, h.Level())
 }
 
 // MatchFilterHandler returns a Handler that only writes records
@@ -158,8 +165,7 @@ func FilterHandler(fn func(r *Record) bool, h Handler) Handler {
 // context matches the value. For example, to only log records
 // from your ui package:
 //
-//    log.MatchFilterHandler("pkg", "app/ui", log.StdoutHandler)
-//
+//	log.MatchFilterHandler("pkg", "app/ui", log.StdoutHandler)
 func MatchFilterHandler(key string, value interface{}, h Handler) Handler {
 	return FilterHandler(func(r *Record) (pass bool) {
 		switch key {
@@ -185,8 +191,7 @@ func MatchFilterHandler(key string, value interface{}, h Handler) Handler {
 // level to the wrapped Handler. For example, to only
 // log Error/Crit records:
 //
-//     log.LvlFilterHandler(log.LvlError, log.StdoutHandler)
-//
+//	log.LvlFilterHandler(log.LvlError, log.StdoutHandler)
 func LvlFilterHandler(maxLvl Lvl, h Handler) Handler {
 	return FilterHandler(func(r *Record) (pass bool) {
 		return r.Lvl <= maxLvl
@@ -198,10 +203,9 @@ func LvlFilterHandler(maxLvl Lvl, h Handler) Handler {
 // to different locations. For example, to log to a file and
 // standard error:
 //
-//     log.MultiHandler(
-//         log.Must.FileHandler("/var/log/app.log", log.LogfmtFormat()),
-//         log.StderrHandler)
-//
+//	log.MultiHandler(
+//	    log.Must.FileHandler("/var/log/app.log", log.LogfmtFormat()),
+//	    log.StderrHandler)
 func MultiHandler(hs ...Handler) Handler {
 	return FuncHandler(func(r *Record) error {
 		for _, h := range hs {
@@ -209,7 +213,7 @@ func MultiHandler(hs ...Handler) Handler {
 			h.Log(r)
 		}
 		return nil
-	})
+	}, LvlDebug)
 }
 
 // FailoverHandler writes all log records to the first handler
@@ -219,10 +223,10 @@ func MultiHandler(hs ...Handler) Handler {
 // to writing to a file if the network fails, and then to
 // standard out if the file write fails:
 //
-//     log.FailoverHandler(
-//         log.Must.NetHandler("tcp", ":9090", log.JSONFormat()),
-//         log.Must.FileHandler("/var/log/app.log", log.LogfmtFormat()),
-//         log.StdoutHandler)
+//	log.FailoverHandler(
+//	    log.Must.NetHandler("tcp", ":9090", log.JSONFormat()),
+//	    log.Must.FileHandler("/var/log/app.log", log.LogfmtFormat()),
+//	    log.StdoutHandler)
 //
 // All writes that do not go to the first handler will add context with keys of
 // the form "failover_err_{idx}" which explain the error encountered while
@@ -239,17 +243,17 @@ func FailoverHandler(hs ...Handler) Handler {
 		}
 
 		return err
-	})
+	}, LvlTrace)
 }
 
 // ChannelHandler writes all records to the given channel.
 // It blocks if the channel is full. Useful for async processing
 // of log messages, it's used by BufferedHandler.
-func ChannelHandler(recs chan<- *Record) Handler {
+func ChannelHandler(recs chan<- *Record, lvl Lvl) Handler {
 	return FuncHandler(func(r *Record) error {
 		recs <- r
 		return nil
-	})
+	}, lvl)
 }
 
 // BufferedHandler writes all records to a buffered
@@ -264,7 +268,8 @@ func BufferedHandler(bufSize int, h Handler) Handler {
 			_ = h.Log(m)
 		}
 	}()
-	return ChannelHandler(recs)
+
+	return ChannelHandler(recs, h.Level())
 }
 
 // LazyHandler writes all values to the wrapped handler after evaluating
@@ -297,7 +302,7 @@ func LazyHandler(h Handler) Handler {
 		}
 
 		return h.Log(r)
-	})
+	}, h.Level())
 }
 
 func evaluateLazy(lz Lazy) (interface{}, error) {
@@ -333,7 +338,7 @@ func evaluateLazy(lz Lazy) (interface{}, error) {
 func DiscardHandler() Handler {
 	return FuncHandler(func(r *Record) error {
 		return nil
-	})
+	}, LvlDiscard)
 }
 
 // Must provides the following Handler creation functions

log/handler_glog.go

@@ -82,14 +82,14 @@ func (h *GlogHandler) Verbosity(level Lvl) {
 //
 // For instance:
 //
-//  pattern="gopher.go=3"
-//   sets the V level to 3 in all Go files named "gopher.go"
+//	pattern="gopher.go=3"
+//	 sets the V level to 3 in all Go files named "gopher.go"
 //
-//  pattern="foo=3"
-//   sets V to 3 in all files of any packages whose import path ends in "foo"
+//	pattern="foo=3"
+//	 sets V to 3 in all files of any packages whose import path ends in "foo"
 //
-//  pattern="foo/*=3"
-//   sets V to 3 in all files of any packages whose import path contains "foo"
+//	pattern="foo/*=3"
+//	 sets V to 3 in all files of any packages whose import path contains "foo"
 func (h *GlogHandler) Vmodule(ruleset string) error {
 	var filter []pattern
 	for _, rule := range strings.Split(ruleset, ",") {
@@ -230,3 +230,7 @@ func (h *GlogHandler) Log(r *Record) error {
 	}
 	return nil
 }
+
+func (h *GlogHandler) Level() Lvl {
+	return Lvl(atomic.LoadUint32(&h.level))
+}

log/handler_go119.go

@@ -0,0 +1,27 @@
+//+go:build go1.19
+
+package log
+
+import "sync/atomic"
+
+// swapHandler wraps another handler that may be swapped out
+// dynamically at runtime in a thread-safe fashion.
+type swapHandler struct {
+	handler atomic.Pointer[Handler]
+}
+
+func (h *swapHandler) Log(r *Record) error {
+	return (*h.handler.Load()).Log(r)
+}
+
+func (h *swapHandler) Swap(newHandler Handler) {
+	h.handler.Store(&newHandler)
+}
+
+func (h *swapHandler) Get() Handler {
+	return *h.handler.Load()
+}
+
+func (h *swapHandler) Level() Lvl {
+	return (*h.handler.Load()).Level()
+}

log/handler_go14.go

@@ -1,5 +1,4 @@
-//go:build go1.4
-// +build go1.4
+//go:build !go1.19
 
 package log
 

log/logger.go

@@ -18,7 +18,8 @@ const skipLevel = 2
 type Lvl int
 
 const (
-	LvlCrit Lvl = iota
+	LvlDiscard Lvl = -1
+	LvlCrit    Lvl = iota
 	LvlError
 	LvlWarn
 	LvlInfo
@@ -131,6 +132,10 @@ type logger struct {
 }
 
 func (l *logger) write(msg string, lvl Lvl, ctx []interface{}, skip int) {
+	if l.h.Level() < lvl {
+		return
+	}
+
 	l.h.Log(&Record{
 		Time: time.Now(),
 		Lvl:  lvl,

log/syslog.go

@@ -45,7 +45,7 @@ func sharedSyslog(fmtr Format, sysWr *syslog.Writer, err error) (Handler, error)
 
 		s := strings.TrimSpace(string(fmtr.Format(r)))
 		return syslogFn(s)
-	})
+	}, LvlTrace)
 	return LazyHandler(&closingHandler{sysWr, h}), nil
 }
 

p2p/discover/v4_udp_test.go

@@ -562,7 +562,7 @@ func startLocalhostV4(t *testing.T, cfg Config) *UDPv4 {
 	cfg.Log.SetHandler(log.FuncHandler(func(r *log.Record) error {
 		t.Logf("%s %s", lprefix, lfmt.Format(r))
 		return nil
-	}))
+	}, log.LvlTrace))
 
 	// Listen.
 	socket, err := net.ListenUDP("udp4", &net.UDPAddr{IP: net.IP{127, 0, 0, 1}})

p2p/discover/v5_udp_test.go

@@ -83,7 +83,7 @@ func startLocalhostV5(t *testing.T, cfg Config) *UDPv5 {
 	cfg.Log.SetHandler(log.FuncHandler(func(r *log.Record) error {
 		t.Logf("%s %s", lprefix, lfmt.Format(r))
 		return nil
-	}))
+	}, log.LvlTrace))
 
 	// Listen.
 	socket, err := net.ListenUDP("udp4", &net.UDPAddr{IP: net.IP{127, 0, 0, 1}})