all: more linters (#24783)

This enables the following linters

- typecheck
- unused
- staticcheck
- bidichk
- durationcheck
- exportloopref
- gosec

WIth a few exceptions.

- We use a deprecated protobuf in trezor. I didn't want to mess with that, since I cannot meaningfully test any changes there.
- The deprecated TypeMux is used in a few places still, so the warning for it is silenced for now.
- Using string type in context.WithValue is apparently wrong, one should use a custom type, to prevent collisions between different places in the hierarchy of callers. That should be fixed at some point, but may require some attention.
- The warnings for using weak random generator are squashed, since we use a lot of random without need for cryptographic guarantees.

eth/discovery.go

@@ -1,63 +0,0 @@
-// Copyright 2020 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-package eth
-
-import (
-	"github.com/ethereum/go-ethereum/core"
-	"github.com/ethereum/go-ethereum/core/forkid"
-	"github.com/ethereum/go-ethereum/p2p/enode"
-	"github.com/ethereum/go-ethereum/rlp"
-)
-
-// ethEntry is the "eth" ENR entry which advertises eth protocol
-// on the discovery network.
-type ethEntry struct {
-	ForkID forkid.ID // Fork identifier per EIP-2124
-
-	// Ignore additional fields (for forward compatibility).
-	Rest []rlp.RawValue `rlp:"tail"`
-}
-
-// ENRKey implements enr.Entry.
-func (e ethEntry) ENRKey() string {
-	return "eth"
-}
-
-// startEthEntryUpdate starts the ENR updater loop.
-func (eth *Ethereum) startEthEntryUpdate(ln *enode.LocalNode) {
-	var newHead = make(chan core.ChainHeadEvent, 10)
-	sub := eth.blockchain.SubscribeChainHeadEvent(newHead)
-
-	go func() {
-		defer sub.Unsubscribe()
-		for {
-			select {
-			case <-newHead:
-				ln.Set(eth.currentEthEntry())
-			case <-sub.Err():
-				// Would be nice to sync with eth.Stop, but there is no
-				// good way to do that.
-				return
-			}
-		}
-	}()
-}
-
-func (eth *Ethereum) currentEthEntry() *ethEntry {
-	return &ethEntry{ForkID: forkid.NewID(eth.blockchain.Config(), eth.blockchain.Genesis().Hash(),
-		eth.blockchain.CurrentHeader().Number.Uint64())}
-}

eth/downloader/downloader.go

@@ -131,7 +131,6 @@ type Downloader struct {
 	pivotHeader *types.Header // Pivot block header to dynamically push the syncing state root
 	pivotLock   sync.RWMutex  // Lock protecting pivot header reads from updates
 
-	snapSync       bool         // Whether to run state sync over the snap protocol
 	SnapSyncer     *snap.Syncer // TODO(karalabe): make private! hack for now
 	stateSyncStart chan *stateSync
 

eth/filters/api.go

@@ -257,6 +257,7 @@ func (api *PublicFilterAPI) Logs(ctx context.Context, crit FilterCriteria) (*rpc
 			select {
 			case logs := <-matchedLogs:
 				for _, log := range logs {
+					log := log
 					notifier.Notify(rpcSub.ID, &log)
 				}
 			case <-rpcSub.Err(): // client send an unsubscribe request

eth/filters/bench_test.go

@@ -93,9 +93,9 @@ func benchmarkBloomBits(b *testing.B, sectionSize uint64) {
 		var header *types.Header
 		for i := sectionIdx * sectionSize; i < (sectionIdx+1)*sectionSize; i++ {
 			hash := rawdb.ReadCanonicalHash(db, i)
-			header = rawdb.ReadHeader(db, hash, i)
-			if header == nil {
+			if header = rawdb.ReadHeader(db, hash, i); header == nil {
 				b.Fatalf("Error creating bloomBits data")
+				return
 			}
 			bc.AddBloom(uint(i-sectionIdx*sectionSize), header.Bloom)
 		}
@@ -144,9 +144,9 @@ func benchmarkBloomBits(b *testing.B, sectionSize uint64) {
 	db.Close()
 }
 
-var bloomBitsPrefix = []byte("bloomBits-")
-
+//nolint:unused
 func clearBloomBits(db ethdb.Database) {
+	var bloomBitsPrefix = []byte("bloomBits-")
 	fmt.Println("Clearing bloombits data...")
 	it := db.NewIterator(bloomBitsPrefix, nil)
 	for it.Next() {

eth/filters/filter_system_test.go

@@ -44,7 +44,6 @@ var (
 )
 
 type testBackend struct {
-	mux             *event.TypeMux
 	db              ethdb.Database
 	sections        uint64
 	txFeed          event.Feed

eth/peer.go

@@ -34,8 +34,7 @@ type ethPeerInfo struct {
 // ethPeer is a wrapper around eth.Peer to maintain a few extra metadata.
 type ethPeer struct {
 	*eth.Peer
-	snapExt  *snapPeer     // Satellite `snap` connection
-	snapWait chan struct{} // Notification channel for snap connections
+	snapExt *snapPeer // Satellite `snap` connection
 }
 
 // info gathers and returns some `eth` protocol metadata known about a peer.

eth/protocols/snap/sort_test.go

@@ -67,10 +67,9 @@ func TestRequestSorting(t *testing.T) {
 		"0x01234567890123456789012345678901012345678901234567890123456789010",
 		"0x01234567890123456789012345678901012345678901234567890123456789011",
 	} {
-		sp, tnps, hash := f(x)
+		sp, _, hash := f(x)
 		hashes = append(hashes, hash)
 		paths = append(paths, sp)
-		pathsets = append(pathsets, tnps)
 	}
 	_, paths, pathsets = sortByAccountPath(hashes, paths)
 	{

eth/protocols/snap/sync.go

@@ -2781,7 +2781,7 @@ func (s *Syncer) onHealState(paths [][]byte, value []byte) error {
 	if len(paths) == 1 {
 		var account types.StateAccount
 		if err := rlp.DecodeBytes(value, &account); err != nil {
-			return nil
+			return nil // Returning the error here would drop the remote peer
 		}
 		blob := snapshot.SlimAccountRLP(account.Nonce, account.Balance, account.Root, account.CodeHash)
 		rawdb.WriteAccountSnapshot(s.stateWriter, common.BytesToHash(paths[0]), blob)

eth/protocols/snap/sync_test.go

@@ -1661,7 +1661,7 @@ func TestSyncAccountPerformance(t *testing.T) {
 	// Doing so would bring this number down to zero in this artificial testcase,
 	// but only add extra IO for no reason in practice.
 	if have, want := src.nTrienodeRequests, 1; have != want {
-		fmt.Printf(src.Stats())
+		fmt.Print(src.Stats())
 		t.Errorf("trie node heal requests wrong, want %d, have %d", want, have)
 	}
 }

eth/tracers/tracers_test.go

@@ -21,7 +21,6 @@ import (
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/rawdb"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -32,20 +31,6 @@ import (
 	"github.com/ethereum/go-ethereum/tests"
 )
 
-// callTrace is the result of a callTracer run.
-type callTrace struct {
-	Type    string          `json:"type"`
-	From    common.Address  `json:"from"`
-	To      common.Address  `json:"to"`
-	Input   hexutil.Bytes   `json:"input"`
-	Output  hexutil.Bytes   `json:"output"`
-	Gas     *hexutil.Uint64 `json:"gas,omitempty"`
-	GasUsed *hexutil.Uint64 `json:"gasUsed,omitempty"`
-	Value   *hexutil.Big    `json:"value,omitempty"`
-	Error   string          `json:"error,omitempty"`
-	Calls   []callTrace     `json:"calls,omitempty"`
-}
-
 func BenchmarkTransactionTrace(b *testing.B) {
 	key, _ := crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
 	from := crypto.PubkeyToAddress(key.PublicKey)