From 12d7d04b3139ab8dffb23ab0e35035a94ea1c401 Mon Sep 17 00:00:00 2001
From: Oliver Gugger <gugger@gmail.com>
Date: Mon, 27 Sep 2021 14:27:51 +0200
Subject: [PATCH] multi: fix linter issues

---
 address.go                     | 10 +++++-----
 address_test.go                |  2 +-
 base58/base58check.go          |  2 +-
 base58/base58check_test.go     | 11 +++++++----
 bech32/bech32.go               |  6 +++---
 bloom/merkleblock.go           |  2 +-
 certgen.go                     |  2 +-
 coinset/coins_test.go          |  2 +-
 gcs/builder/builder.go         |  4 ++--
 gcs/builder/builder_test.go    |  3 ---
 gcs/gcs.go                     |  6 +++---
 gcs/gcs_test.go                |  4 +++-
 gcs/gcsbench_test.go           | 11 +++++++----
 hash160.go                     |  2 +-
 hdkeychain/bench_test.go       |  8 ++++----
 hdkeychain/extendedkey.go      |  6 +++---
 hdkeychain/extendedkey_test.go |  2 +-
 wif_test.go                    |  4 ++++
 18 files changed, 48 insertions(+), 39 deletions(-)

diff --git a/address.go b/address.go
index 8672497..75503ed 100644
--- a/address.go
+++ b/address.go
@@ -41,7 +41,7 @@ var (
 
 	// ErrUnknownAddressType describes an error where an address can not
 	// decoded as a specific address type due to the string encoding
-	// begining with an identifier byte unknown to any standard or
+	// beginning with an identifier byte unknown to any standard or
 	// registered (via chaincfg.Register) network.
 	ErrUnknownAddressType = errors.New("unknown address type")
 
@@ -265,7 +265,7 @@ func NewAddressPubKeyHash(pkHash []byte, net *chaincfg.Params) (*AddressPubKeyHa
 // newAddressPubKeyHash is the internal API to create a pubkey hash address
 // with a known leading identifier byte for a network, rather than looking
 // it up through its parameters.  This is useful when creating a new address
-// structure from a string encoding where the identifer byte is already
+// structure from a string encoding where the identifier byte is already
 // known.
 func newAddressPubKeyHash(pkHash []byte, netID byte) (*AddressPubKeyHash, error) {
 	// Check for a valid pubkey hash length.
@@ -304,7 +304,7 @@ func (a *AddressPubKeyHash) String() string {
 }
 
 // Hash160 returns the underlying array of the pubkey hash.  This can be useful
-// when an array is more appropiate than a slice (for example, when used as map
+// when an array is more appropriate than a slice (for example, when used as map
 // keys).
 func (a *AddressPubKeyHash) Hash160() *[ripemd160.Size]byte {
 	return &a.hash
@@ -332,7 +332,7 @@ func NewAddressScriptHashFromHash(scriptHash []byte, net *chaincfg.Params) (*Add
 // newAddressScriptHashFromHash is the internal API to create a script hash
 // address with a known leading identifier byte for a network, rather than
 // looking it up through its parameters.  This is useful when creating a new
-// address structure from a string encoding where the identifer byte is already
+// address structure from a string encoding where the identifier byte is already
 // known.
 func newAddressScriptHashFromHash(scriptHash []byte, netID byte) (*AddressScriptHash, error) {
 	// Check for a valid script hash length.
@@ -371,7 +371,7 @@ func (a *AddressScriptHash) String() string {
 }
 
 // Hash160 returns the underlying array of the script hash.  This can be useful
-// when an array is more appropiate than a slice (for example, when used as map
+// when an array is more appropriate than a slice (for example, when used as map
 // keys).
 func (a *AddressScriptHash) Hash160() *[ripemd160.Size]byte {
 	return &a.hash
diff --git a/address_test.go b/address_test.go
index b6a990d..bbca3de 100644
--- a/address_test.go
+++ b/address_test.go
@@ -766,7 +766,7 @@ func TestAddresses(t *testing.T) {
 			// Encode again and compare against the original.
 			encoded := decoded.EncodeAddress()
 			if test.encoded != encoded {
-				t.Errorf("%v: decoding and encoding produced different addressess: %v != %v",
+				t.Errorf("%v: decoding and encoding produced different addresses: %v != %v",
 					test.name, test.encoded, encoded)
 				return
 			}
diff --git a/base58/base58check.go b/base58/base58check.go
index 7cdafee..402c323 100644
--- a/base58/base58check.go
+++ b/base58/base58check.go
@@ -28,7 +28,7 @@ func checksum(input []byte) (cksum [4]byte) {
 func CheckEncode(input []byte, version byte) string {
 	b := make([]byte, 0, 1+len(input)+4)
 	b = append(b, version)
-	b = append(b, input[:]...)
+	b = append(b, input...)
 	cksum := checksum(b)
 	b = append(b, cksum[:]...)
 	return Encode(b)
diff --git a/base58/base58check_test.go b/base58/base58check_test.go
index 7c6350b..20a4177 100644
--- a/base58/base58check_test.go
+++ b/base58/base58check_test.go
@@ -37,11 +37,14 @@ func TestBase58Check(t *testing.T) {
 
 		// test decoding
 		res, version, err := base58.CheckDecode(test.out)
-		if err != nil {
+		switch {
+		case err != nil:
 			t.Errorf("CheckDecode test #%d failed with err: %v", x, err)
-		} else if version != test.version {
+
+		case version != test.version:
 			t.Errorf("CheckDecode test #%d failed: got version: %d want: %d", x, version, test.version)
-		} else if string(res) != test.in {
+
+		case string(res) != test.in:
 			t.Errorf("CheckDecode test #%d failed: got: %s want: %s", x, res, test.in)
 		}
 	}
@@ -56,7 +59,7 @@ func TestBase58Check(t *testing.T) {
 	// bytes are missing).
 	testString := ""
 	for len := 0; len < 4; len++ {
-		testString = testString + "x"
+		testString += "x"
 		_, _, err = base58.CheckDecode(testString)
 		if err != base58.ErrInvalidFormat {
 			t.Error("Checkdecode test failed, expected ErrInvalidFormat")
diff --git a/bech32/bech32.go b/bech32/bech32.go
index 1bc75a3..c1e0010 100644
--- a/bech32/bech32.go
+++ b/bech32/bech32.go
@@ -362,7 +362,7 @@ func ConvertBits(data []byte, fromBits, toBits uint8, pad bool) ([]byte, error)
 	for _, b := range data {
 
 		// Discard unused bits.
-		b = b << (8 - fromBits)
+		b <<= 8 - fromBits
 
 		// How many bits remaining to extract from the input data.
 		remFromBits := fromBits
@@ -383,7 +383,7 @@ func ConvertBits(data []byte, fromBits, toBits uint8, pad bool) ([]byte, error)
 
 			// Discard the bits we just extracted and get ready for
 			// next iteration.
-			b = b << toExtract
+			b <<= toExtract
 			remFromBits -= toExtract
 			filledBits += toExtract
 
@@ -399,7 +399,7 @@ func ConvertBits(data []byte, fromBits, toBits uint8, pad bool) ([]byte, error)
 
 	// We pad any unfinished group if specified.
 	if pad && filledBits > 0 {
-		nextByte = nextByte << (toBits - filledBits)
+		nextByte <<= toBits - filledBits
 		regrouped = append(regrouped, nextByte)
 		filledBits = 0
 		nextByte = 0
diff --git a/bloom/merkleblock.go b/bloom/merkleblock.go
index d6796ba..b1da716 100644
--- a/bloom/merkleblock.go
+++ b/bloom/merkleblock.go
@@ -116,7 +116,7 @@ func NewMerkleBlock(block *btcutil.Block, filter *Filter) (*wire.MsgMerkleBlock,
 		Flags:        make([]byte, (len(mBlock.bits)+7)/8),
 	}
 	for _, hash := range mBlock.finalHashes {
-		msgMerkleBlock.AddTxHash(hash)
+		_ = msgMerkleBlock.AddTxHash(hash)
 	}
 	for i := uint32(0); i < uint32(len(mBlock.bits)); i++ {
 		msgMerkleBlock.Flags[i/8] |= mBlock.bits[i] << (i % 8)
diff --git a/certgen.go b/certgen.go
index bbc45a4..52e2d9c 100644
--- a/certgen.go
+++ b/certgen.go
@@ -61,7 +61,7 @@ func NewTLSCertPair(organization string, validUntil time.Time, extraHosts []stri
 
 	addIP := func(ipAddr net.IP) {
 		for _, ip := range ipAddresses {
-			if bytes.Equal(ip, ipAddr) {
+			if ip.Equal(ipAddr) {
 				return
 			}
 		}
diff --git a/coinset/coins_test.go b/coinset/coins_test.go
index d8ca496..dc02d9f 100644
--- a/coinset/coins_test.go
+++ b/coinset/coins_test.go
@@ -33,7 +33,7 @@ func (c *TestCoin) ValueAge() int64       { return int64(c.TxValue) * c.TxNumCon
 
 func NewCoin(index int64, value btcutil.Amount, numConfs int64) coinset.Coin {
 	h := sha256.New()
-	h.Write([]byte(fmt.Sprintf("%d", index)))
+	_, _ = h.Write([]byte(fmt.Sprintf("%d", index)))
 	hash, _ := chainhash.NewHash(h.Sum(nil))
 	c := &TestCoin{
 		TxHash:     hash,
diff --git a/gcs/builder/builder.go b/gcs/builder/builder.go
index adef5c9..8b45d78 100644
--- a/gcs/builder/builder.go
+++ b/gcs/builder/builder.go
@@ -54,7 +54,7 @@ func RandomKey() ([gcs.KeySize]byte, error) {
 	}
 
 	// Copy the byte slice to a [gcs.KeySize]byte array and return it.
-	copy(key[:], randKey[:])
+	copy(key[:], randKey)
 	return key, nil
 }
 
@@ -62,7 +62,7 @@ func RandomKey() ([gcs.KeySize]byte, error) {
 // truncating the bytes of the hash to the appopriate key size.
 func DeriveKey(keyHash *chainhash.Hash) [gcs.KeySize]byte {
 	var key [gcs.KeySize]byte
-	copy(key[:], keyHash.CloneBytes()[:])
+	copy(key[:], keyHash.CloneBytes())
 	return key
 }
 
diff --git a/gcs/builder/builder_test.go b/gcs/builder/builder_test.go
index 8e9566f..de04421 100644
--- a/gcs/builder/builder_test.go
+++ b/gcs/builder/builder_test.go
@@ -19,9 +19,6 @@ import (
 )
 
 var (
-	// No need to allocate an err variable in every test
-	err error
-
 	// List of values for building a filter
 	contents = [][]byte{
 		[]byte("Alex"),
diff --git a/gcs/gcs.go b/gcs/gcs.go
index cfe215c..fbffb06 100644
--- a/gcs/gcs.go
+++ b/gcs/gcs.go
@@ -91,7 +91,7 @@ type Filter struct {
 // BuildGCSFilter builds a new GCS filter with the collision probability of
 // `1/(2**P)`, key `key`, and including every `[]byte` in `data` as a member of
 // the set.
-func BuildGCSFilter(P uint8, M uint64, key [KeySize]byte, data [][]byte) (*Filter, error) {
+func BuildGCSFilter(P uint8, M uint64, key [KeySize]byte, data [][]byte) (*Filter, error) { // nolint:gocritic
 	// Some initial parameter checks: make sure we have data from which to
 	// build the filter, and make sure our parameters will fit the hash
 	// function we're using.
@@ -174,7 +174,7 @@ func BuildGCSFilter(P uint8, M uint64, key [KeySize]byte, data [][]byte) (*Filte
 
 // FromBytes deserializes a GCS filter from a known N, P, and serialized filter
 // as returned by Bytes().
-func FromBytes(N uint32, P uint8, M uint64, d []byte) (*Filter, error) {
+func FromBytes(N uint32, P uint8, M uint64, d []byte) (*Filter, error) { // nolint:gocritic
 	// Basic sanity check.
 	if P > 32 {
 		return nil, ErrPTooBig
@@ -200,7 +200,7 @@ func FromBytes(N uint32, P uint8, M uint64, d []byte) (*Filter, error) {
 
 // FromNBytes deserializes a GCS filter from a known P, and serialized N and
 // filter as returned by NBytes().
-func FromNBytes(P uint8, M uint64, d []byte) (*Filter, error) {
+func FromNBytes(P uint8, M uint64, d []byte) (*Filter, error) { // nolint:gocritic
 	buffer := bytes.NewBuffer(d)
 	N, err := wire.ReadVarInt(buffer, varIntProtoVer)
 	if err != nil {
diff --git a/gcs/gcs_test.go b/gcs/gcs_test.go
index 369b773..bb4d550 100644
--- a/gcs/gcs_test.go
+++ b/gcs/gcs_test.go
@@ -27,7 +27,7 @@ var (
 	// Filters are conserved between tests but we must define with an
 	// interface which functions we're testing because the gcsFilter type
 	// isn't exported
-	filter, filter2, filter3, filter4, filter5 *gcs.Filter
+	filter, filter2, filter3 *gcs.Filter
 
 	// We need to use the same key for building and querying the filters
 	key [gcs.KeySize]byte
@@ -328,6 +328,8 @@ func TestGCSFilterMatchAnySuite(t *testing.T) {
 	}
 
 	for _, test := range funcs {
+		test := test
+
 		t.Run(test.name, func(t *testing.T) {
 			contentsCopy := make([][]byte, len(contents2))
 			copy(contentsCopy, contents2)
diff --git a/gcs/gcsbench_test.go b/gcs/gcsbench_test.go
index 58795eb..ffb2599 100644
--- a/gcs/gcsbench_test.go
+++ b/gcs/gcsbench_test.go
@@ -28,7 +28,6 @@ func genRandFilterElements(numElements uint) ([][]byte, error) {
 
 var (
 	generatedFilter *gcs.Filter
-	filterErr       error
 )
 
 // BenchmarkGCSFilterBuild benchmarks building a filter.
@@ -101,7 +100,7 @@ func BenchmarkGCSFilterMatch(b *testing.B) {
 
 	var localMatch bool
 	for i := 0; i < b.N; i++ {
-		localMatch, err = filter.Match(key, []byte("Nate"))
+		_, err = filter.Match(key, []byte("Nate"))
 		if err != nil {
 			b.Fatalf("unable to match filter: %v", err)
 		}
@@ -115,8 +114,6 @@ func BenchmarkGCSFilterMatch(b *testing.B) {
 }
 
 var (
-	randElems1, _        = genRandFilterElements(1)
-	randElems10, _       = genRandFilterElements(10)
 	randElems100, _      = genRandFilterElements(100)
 	randElems1000, _     = genRandFilterElements(1000)
 	randElems10000, _    = genRandFilterElements(10000)
@@ -164,6 +161,8 @@ var matchAnyBenchmarks = []struct {
 // BenchmarkGCSFilterMatchAny benchmarks the sort-and-zip MatchAny impl.
 func BenchmarkGCSFilterZipMatchAny(b *testing.B) {
 	for _, test := range matchAnyBenchmarks {
+		test := test
+
 		b.Run(test.name, func(b *testing.B) {
 			b.ReportAllocs()
 
@@ -188,6 +187,8 @@ func BenchmarkGCSFilterZipMatchAny(b *testing.B) {
 // BenchmarkGCSFilterMatchAny benchmarks the hash-join MatchAny impl.
 func BenchmarkGCSFilterHashMatchAny(b *testing.B) {
 	for _, test := range matchAnyBenchmarks {
+		test := test
+
 		b.Run(test.name, func(b *testing.B) {
 			b.ReportAllocs()
 
@@ -212,6 +213,8 @@ func BenchmarkGCSFilterHashMatchAny(b *testing.B) {
 // BenchmarkGCSFilterMatchAny benchmarks the hybrid MatchAny impl.
 func BenchmarkGCSFilterMatchAny(b *testing.B) {
 	for _, test := range matchAnyBenchmarks {
+		test := test
+
 		b.Run(test.name, func(b *testing.B) {
 			b.ReportAllocs()
 
diff --git a/hash160.go b/hash160.go
index 599a0fe..fa26e09 100644
--- a/hash160.go
+++ b/hash160.go
@@ -13,7 +13,7 @@ import (
 
 // Calculate the hash of hasher over buf.
 func calcHash(buf []byte, hasher hash.Hash) []byte {
-	hasher.Write(buf)
+	_, _ = hasher.Write(buf)
 	return hasher.Sum(nil)
 }
 
diff --git a/hdkeychain/bench_test.go b/hdkeychain/bench_test.go
index 583eef0..7c86ca9 100644
--- a/hdkeychain/bench_test.go
+++ b/hdkeychain/bench_test.go
@@ -26,7 +26,7 @@ func BenchmarkDeriveHardened(b *testing.B) {
 	b.StartTimer()
 
 	for i := 0; i < b.N; i++ {
-		masterKey.Derive(hdkeychain.HardenedKeyStart)
+		_, _ = masterKey.Derive(hdkeychain.HardenedKeyStart)
 	}
 }
 
@@ -41,7 +41,7 @@ func BenchmarkDeriveNormal(b *testing.B) {
 	b.StartTimer()
 
 	for i := 0; i < b.N; i++ {
-		masterKey.Derive(0)
+		_, _ = masterKey.Derive(0)
 	}
 }
 
@@ -56,7 +56,7 @@ func BenchmarkPrivToPub(b *testing.B) {
 	b.StartTimer()
 
 	for i := 0; i < b.N; i++ {
-		masterKey.Neuter()
+		_, _ = masterKey.Neuter()
 	}
 }
 
@@ -64,7 +64,7 @@ func BenchmarkPrivToPub(b *testing.B) {
 // extended key.
 func BenchmarkDeserialize(b *testing.B) {
 	for i := 0; i < b.N; i++ {
-		hdkeychain.NewKeyFromString(bip0032MasterPriv1)
+		_, _ = hdkeychain.NewKeyFromString(bip0032MasterPriv1)
 	}
 }
 
diff --git a/hdkeychain/extendedkey.go b/hdkeychain/extendedkey.go
index a0c5e7b..929fe99 100644
--- a/hdkeychain/extendedkey.go
+++ b/hdkeychain/extendedkey.go
@@ -277,7 +277,7 @@ func (k *ExtendedKey) Derive(i uint32) (*ExtendedKey, error) {
 	// data:
 	//   I = HMAC-SHA512(Key = chainCode, Data = data)
 	hmac512 := hmac.New(sha512.New, k.chainCode)
-	hmac512.Write(data)
+	_, _ = hmac512.Write(data)
 	ilr := hmac512.Sum(nil)
 
 	// Split "I" into two 32-byte sequences Il and Ir where:
@@ -380,7 +380,7 @@ func (k *ExtendedKey) DeriveNonStandard(i uint32) (*ExtendedKey, error) {
 	binary.BigEndian.PutUint32(data[keyLen:], i)
 
 	hmac512 := hmac.New(sha512.New, k.chainCode)
-	hmac512.Write(data)
+	_, _ = hmac512.Write(data)
 	ilr := hmac512.Sum(nil)
 
 	il := ilr[:len(ilr)/2]
@@ -610,7 +610,7 @@ func NewMaster(seed []byte, net *chaincfg.Params) (*ExtendedKey, error) {
 	// First take the HMAC-SHA512 of the master key and the seed data:
 	//   I = HMAC-SHA512(Key = "Bitcoin seed", Data = S)
 	hmac512 := hmac.New(sha512.New, masterKey)
-	hmac512.Write(seed)
+	_, _ = hmac512.Write(seed)
 	lr := hmac512.Sum(nil)
 
 	// Split "I" into two 32-byte sequences Il and Ir where:
diff --git a/hdkeychain/extendedkey_test.go b/hdkeychain/extendedkey_test.go
index 37a42fa..dd6deb5 100644
--- a/hdkeychain/extendedkey_test.go
+++ b/hdkeychain/extendedkey_test.go
@@ -983,7 +983,7 @@ func TestZero(t *testing.T) {
 		wantAddr := "1HT7xU2Ngenf7D4yocz2SAcnNLW7rK8d4E"
 		addr, err := key.Address(&chaincfg.MainNetParams)
 		if err != nil {
-			t.Errorf("Addres s #%d (%s): unexpected error: %v", i,
+			t.Errorf("Address #%d (%s): unexpected error: %v", i,
 				testName, err)
 			return false
 		}
diff --git a/wif_test.go b/wif_test.go
index dec6dd6..589f2ac 100644
--- a/wif_test.go
+++ b/wif_test.go
@@ -64,6 +64,8 @@ func TestEncodeDecodeWIF(t *testing.T) {
 	}
 
 	for _, validCase := range validEncodeCases {
+		validCase := validCase
+
 		t.Run(validCase.name, func(t *testing.T) {
 			priv, _ := btcec.PrivKeyFromBytes(btcec.S256(), validCase.privateKey)
 			wif, err := NewWIF(priv, validCase.net, validCase.compress)
@@ -122,6 +124,8 @@ func TestEncodeDecodeWIF(t *testing.T) {
 	}
 
 	for _, invalidCase := range invalidDecodeCases {
+		invalidCase := invalidCase
+
 		t.Run(invalidCase.name, func(t *testing.T) {
 			decodedWif, err := DecodeWIF(invalidCase.wif)
 			if decodedWif != nil {