CI: Fix golangci-lint linter issues, add prealloc linter and bump version depends for Go 1.18 (#915)

* Bump CI versions

* Specifically set go version as 1.17.x bumps it to 1.18

* Another

* Adjust AppVeyor

* Part 1 of linter issues

* Part 2

* Fix various linters and improvements

* Part 3

* Finishing touches

* Tests and EqualFold

* Fix nitterinos plus bonus requester jobs bump for exchanges with large number of tests

* Fix nitterinos and bump golangci-lint timeout for AppVeyor

* Address nits, ensure all books are returned on err due to syncer regression

* Fix the wiggins

* Fix duplication

* Fix nitterinos

common/cache/cache_test.go

@@ -2,6 +2,8 @@ package cache
 
 import (
 	"testing"
+
+	"github.com/thrasher-corp/gocryptotrader/common/convert"
 )
 
 func TestCache(t *testing.T) {
@@ -16,12 +18,11 @@ func TestCache(t *testing.T) {
 	if v == nil {
 		t.Fatal("expected cache to contain \"hello\" key")
 	}
-	if v.(string) != "world" {
+	if convert.InterfaceToStringOrZeroValue(v) != "world" {
 		t.Fatal("expected \"hello\" key to contain value \"world\"")
 	}
 
-	r := lruCache.Remove("hello")
-	if !r {
+	if r := lruCache.Remove("hello"); !r {
 		t.Fatal("expected \"hello\" key to be removed from cache")
 	}
 
@@ -77,39 +78,39 @@ func TestAdd(t *testing.T) {
 	if v == nil {
 		t.Fatal("expected cache to contain \"2\" key")
 	}
-	if v.(int) != 2 {
+	if convert.InterfaceToIntOrZeroValue(v) != 2 {
 		t.Fatal("expected \"2\" key to contain value \"2\"")
 	}
 	k, v := lruCache.getNewest()
-	if k.(int) != 2 {
+	if convert.InterfaceToIntOrZeroValue(k) != 2 {
 		t.Fatal("expected latest key to be 2")
 	}
-	if v.(int) != 2 {
+	if convert.InterfaceToIntOrZeroValue(v) != 2 {
 		t.Fatal("expected latest value to be 2")
 	}
 	lruCache.Add(3, 3)
 	k, _ = lruCache.getNewest()
-	if k.(int) != 3 {
+	if convert.InterfaceToIntOrZeroValue(k) != 3 {
 		t.Fatal("expected latest key to be 3")
 	}
 	k, _ = lruCache.getOldest()
-	if k.(int) != 2 {
+	if convert.InterfaceToIntOrZeroValue(k) != 2 {
 		t.Fatal("expected oldest key to be 2")
 	}
 	k, v = lruCache.getOldest()
-	if k.(int) != 2 {
+	if convert.InterfaceToIntOrZeroValue(k) != 2 {
 		t.Fatal("expected oldest key to be 2")
 	}
-	if v.(int) != 2 {
+	if convert.InterfaceToIntOrZeroValue(v) != 2 {
 		t.Fatal("expected latest value to be 2")
 	}
 	lruCache.Add(2, 2)
 	k, _ = lruCache.getNewest()
-	if k.(int) != 2 {
+	if convert.InterfaceToIntOrZeroValue(k) != 2 {
 		t.Fatal("expected latest key to be 2")
 	}
 	k, _ = lruCache.getOldest()
-	if k.(int) != 3 {
+	if convert.InterfaceToIntOrZeroValue(k) != 3 {
 		t.Fatal("expected oldest key to be 3")
 	}
 }

common/cache/lru.go

@@ -24,7 +24,9 @@ func NewLRUCache(capacity uint64) *LRU {
 func (l *LRU) Add(key, value interface{}) {
 	if f, o := l.items[key]; o {
 		l.l.MoveToFront(f)
-		f.Value.(*item).value = value
+		if v, ok := f.Value.(*item); ok {
+			v.value = value
+		}
 		return
 	}
 
@@ -40,7 +42,9 @@ func (l *LRU) Add(key, value interface{}) {
 func (l *LRU) Get(key interface{}) interface{} {
 	if i, f := l.items[key]; f {
 		l.l.MoveToFront(i)
-		return i.Value.(*item).value
+		if v, ok := i.Value.(*item); ok {
+			return v.value
+		}
 	}
 	return nil
 }
@@ -48,7 +52,9 @@ func (l *LRU) Get(key interface{}) interface{} {
 // GetOldest returns the oldest entry
 func (l *LRU) getOldest() (key, value interface{}) {
 	if x := l.l.Back(); x != nil {
-		return x.Value.(*item).key, x.Value.(*item).value
+		if v, ok := x.Value.(*item); ok {
+			return v.key, v.value
+		}
 	}
 	return
 }
@@ -56,7 +62,9 @@ func (l *LRU) getOldest() (key, value interface{}) {
 // GetNewest returns the newest entry
 func (l *LRU) getNewest() (key, value interface{}) {
 	if x := l.l.Front(); x != nil {
-		return x.Value.(*item).key, x.Value.(*item).value
+		if v, ok := x.Value.(*item); ok {
+			return v.key, v.value
+		}
 	}
 	return
 }
@@ -99,5 +107,7 @@ func (l *LRU) removeOldestEntry() {
 // removeElement element from the cache
 func (l *LRU) removeElement(e *list.Element) {
 	l.l.Remove(e)
-	delete(l.items, e.Value.(*item).key)
+	if v, ok := e.Value.(*item); ok {
+		delete(l.items, v.key)
+	}
 }

common/common.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"net/url"
 	"os"
@@ -18,6 +17,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/thrasher-corp/gocryptotrader/common/file"
 	"github.com/thrasher-corp/gocryptotrader/log"
 )
 
@@ -257,7 +257,7 @@ func SendHTTPRequest(ctx context.Context, method, urlPath string, headers map[st
 	}
 	defer resp.Body.Close()
 
-	contents, err := ioutil.ReadAll(resp.Body)
+	contents, err := io.ReadAll(resp.Body)
 
 	if verbose {
 		log.Debugf(log.Global, "HTTP status: %s, Code: %v",
@@ -348,7 +348,7 @@ func CreateDir(dir string) error {
 	}
 
 	log.Warnf(log.Global, "Directory %s does not exist.. creating.\n", dir)
-	return os.MkdirAll(dir, 0770)
+	return os.MkdirAll(dir, file.DefaultPermissionOctal)
 }
 
 // ChangePermission lists all the directories and files in an array
@@ -357,8 +357,8 @@ func ChangePermission(directory string) error {
 		if err != nil {
 			return err
 		}
-		if info.Mode().Perm() != 0770 {
-			return os.Chmod(path, 0770)
+		if info.Mode().Perm() != file.DefaultPermissionOctal {
+			return os.Chmod(path, file.DefaultPermissionOctal)
 		}
 		return nil
 	})

common/common_test.go

@@ -14,6 +14,8 @@ import (
 	"strings"
 	"testing"
 	"time"
+
+	"github.com/thrasher-corp/gocryptotrader/common/file"
 )
 
 func TestSendHTTPRequest(t *testing.T) {
@@ -509,7 +511,7 @@ func TestChangePermission(t *testing.T) {
 		if err == nil {
 			t.Fatal("expected an error on non-existent path")
 		}
-		err = os.Mkdir(testDir, 0777)
+		err = os.Mkdir(testDir, 0o777)
 		if err != nil {
 			t.Fatalf("Mkdir failed. Err: %v", err)
 		}
@@ -530,7 +532,7 @@ func TestChangePermission(t *testing.T) {
 		if err == nil {
 			t.Fatal("expected an error on non-existent path")
 		}
-		err = os.Mkdir(testDir, 0777)
+		err = os.Mkdir(testDir, 0o777)
 		if err != nil {
 			t.Fatalf("Mkdir failed. Err: %v", err)
 		}
@@ -543,8 +545,8 @@ func TestChangePermission(t *testing.T) {
 		if err != nil {
 			t.Fatalf("os.Stat failed. Err: %v", err)
 		}
-		if a.Mode().Perm() != 0770 {
-			t.Fatalf("expected file permissions differ. expecting 0770 got %#o", a.Mode().Perm())
+		if a.Mode().Perm() != file.DefaultPermissionOctal {
+			t.Fatalf("expected file permissions differ. expecting file.DefaultPermissionOctal got %#o", a.Mode().Perm())
 		}
 		err = os.Remove(testDir)
 		if err != nil {

common/convert/convert.go

@@ -119,8 +119,7 @@ func DecimalToHumanFriendlyString(number decimal.Decimal, rounding int, decPoint
 		neg = true
 	}
 	str := number.String()
-	rnd := strings.Split(str, ".")
-	if len(rnd) == 1 {
+	if rnd := strings.Split(str, "."); len(rnd) == 1 {
 		rounding = 0
 	} else if len(rnd[1]) < rounding {
 		rounding = len(rnd[1])
@@ -164,3 +163,27 @@ func numberToHumanFriendlyString(str string, dec int, decPoint, thousandsSep str
 
 	return s
 }
+
+// InterfaceToFloat64OrZeroValue returns the type assertion value or variable zero value
+func InterfaceToFloat64OrZeroValue(r interface{}) float64 {
+	if v, ok := r.(float64); ok {
+		return v
+	}
+	return 0
+}
+
+// InterfaceToIntOrZeroValue returns the type assertion value or variable zero value
+func InterfaceToIntOrZeroValue(r interface{}) int {
+	if v, ok := r.(int); ok {
+		return v
+	}
+	return 0
+}
+
+// InterfaceToStringOrZeroValue returns the type assertion value or variable zero value
+func InterfaceToStringOrZeroValue(r interface{}) string {
+	if v, ok := r.(string); ok {
+		return v
+	}
+	return ""
+}

common/convert/convert_test.go

@@ -282,3 +282,36 @@ func TestNumberToHumanFriendlyString(t *testing.T) {
 		t.Error("expected no comma")
 	}
 }
+
+func TestInterfaceToFloat64OrZeroValue(t *testing.T) {
+	var x interface{}
+	if r := InterfaceToFloat64OrZeroValue(x); r != 0 {
+		t.Errorf("expected 0, got: %v", r)
+	}
+	x = float64(420)
+	if r := InterfaceToFloat64OrZeroValue(x); r != 420 {
+		t.Errorf("expected 420, got: %v", x)
+	}
+}
+
+func TestInterfaceToIntOrZeroValue(t *testing.T) {
+	var x interface{}
+	if r := InterfaceToIntOrZeroValue(x); r != 0 {
+		t.Errorf("expected 0, got: %v", r)
+	}
+	x = int(420)
+	if r := InterfaceToIntOrZeroValue(x); r != 420 {
+		t.Errorf("expected 420, got: %v", x)
+	}
+}
+
+func TestInterfaceToStringOrZeroValue(t *testing.T) {
+	var x interface{}
+	if r := InterfaceToStringOrZeroValue(x); r != "" {
+		t.Errorf("expected empty string, got: %v", r)
+	}
+	x = string("meow")
+	if r := InterfaceToStringOrZeroValue(x); r != "meow" {
+		t.Errorf("expected meow, got: %v", x)
+	}
+}

common/crypto/crypto_test.go

@@ -148,7 +148,7 @@ func TestGetHMAC(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if string(sha1) != string(expectedSha1) {
+	if !bytes.Equal(sha1, expectedSha1) {
 		t.Errorf("Common GetHMAC error: Expected '%x'. Actual '%x'",
 			expectedSha1, sha1,
 		)
@@ -157,7 +157,7 @@ func TestGetHMAC(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if string(sha256) != string(expectedsha256) {
+	if !bytes.Equal(sha256, expectedsha256) {
 		t.Errorf("Common GetHMAC error: Expected '%x'. Actual '%x'",
 			expectedsha256, sha256,
 		)
@@ -166,7 +166,7 @@ func TestGetHMAC(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if string(sha512) != string(expectedsha512) {
+	if !bytes.Equal(sha512, expectedsha512) {
 		t.Errorf("Common GetHMAC error: Expected '%x'. Actual '%x'",
 			expectedsha512, sha512,
 		)
@@ -175,7 +175,7 @@ func TestGetHMAC(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if string(sha512384) != string(expectedsha512384) {
+	if !bytes.Equal(sha512384, expectedsha512384) {
 		t.Errorf("Common GetHMAC error: Expected '%x'. Actual '%x'",
 			expectedsha512384, sha512384,
 		)
@@ -184,7 +184,7 @@ func TestGetHMAC(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if string(md5) != string(expectedmd5) {
+	if !bytes.Equal(md5, expectedmd5) {
 		t.Errorf("Common GetHMAC error: Expected '%x'. Actual '%x'",
 			expectedmd5, md5,
 		)

common/file/archive/zip.go

@@ -8,6 +8,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/thrasher-corp/gocryptotrader/common/file"
 	"github.com/thrasher-corp/gocryptotrader/log"
 )
 
@@ -52,7 +53,7 @@ func UnZip(src, dest string) (fileList []string, err error) {
 			continue
 		}
 
-		err = os.MkdirAll(filepath.Dir(fPath), 0770)
+		err = os.MkdirAll(filepath.Dir(fPath), file.DefaultPermissionOctal)
 		if err != nil {
 			return
 		}

common/file/file.go

@@ -6,22 +6,25 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
+	"io/fs"
 	"os"
 	"path/filepath"
 )
 
+// DefaultPermissionOctal is the default file and folder permission octal used throughout GCT
+const DefaultPermissionOctal fs.FileMode = 0o770
+
 // Write writes selected data to a file or returns an error if it fails. This
 // func also ensures that all files are set to this permission (only rw access
 // for the running user and the group the user is a member of)
 func Write(file string, data []byte) error {
 	basePath := filepath.Dir(file)
 	if !Exists(basePath) {
-		if err := os.MkdirAll(basePath, 0770); err != nil {
+		if err := os.MkdirAll(basePath, DefaultPermissionOctal); err != nil {
 			return err
 		}
 	}
-	return ioutil.WriteFile(file, data, 0770)
+	return os.WriteFile(file, data, DefaultPermissionOctal)
 }
 
 // Writer creates a writer to a file or returns an error if it fails. This
@@ -30,11 +33,11 @@ func Write(file string, data []byte) error {
 func Writer(file string) (*os.File, error) {
 	basePath := filepath.Dir(file)
 	if !Exists(basePath) {
-		if err := os.MkdirAll(basePath, 0770); err != nil {
+		if err := os.MkdirAll(basePath, DefaultPermissionOctal); err != nil {
 			return nil, err
 		}
 	}
-	return os.OpenFile(file, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0770)
+	return os.OpenFile(file, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, DefaultPermissionOctal)
 }
 
 // Move moves a file from a source path to a destination path
@@ -59,7 +62,7 @@ func Move(sourcePath, destPath string) error {
 
 	destDir := filepath.Dir(destPath)
 	if !Exists(destDir) {
-		err = os.MkdirAll(destDir, 0770)
+		err = os.MkdirAll(destDir, DefaultPermissionOctal)
 		if err != nil {
 			return err
 		}

common/file/file_test.go

@@ -56,7 +56,7 @@ func TestWrite(t *testing.T) {
 func TestMove(t *testing.T) {
 	tester := func(in, out string, write bool) error {
 		if write {
-			if err := ioutil.WriteFile(in, []byte("GoCryptoTrader"), 0770); err != nil {
+			if err := os.WriteFile(in, []byte("GoCryptoTrader"), DefaultPermissionOctal); err != nil {
 				return err
 			}
 		}
@@ -65,7 +65,7 @@ func TestMove(t *testing.T) {
 			return err
 		}
 
-		contents, err := ioutil.ReadFile(out)
+		contents, err := os.ReadFile(out)
 		if err != nil {
 			return err
 		}
@@ -124,7 +124,7 @@ func TestExists(t *testing.T) {
 		t.Error("non-existent file should not exist")
 	}
 	tmpFile := filepath.Join(os.TempDir(), "gct-test.txt")
-	if err := ioutil.WriteFile(tmpFile, []byte("hello world"), os.ModeAppend); err != nil {
+	if err := os.WriteFile(tmpFile, []byte("hello world"), os.ModeAppend); err != nil {
 		t.Fatal(err)
 	}
 	if e := Exists(tmpFile); !e {
@@ -258,7 +258,7 @@ func TestWriter(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			if data, err := ioutil.ReadFile(got.Name()); err != nil || string(data) != testData {
+			if data, err := os.ReadFile(got.Name()); err != nil || string(data) != testData {
 				t.Errorf("Could not write the file, or contents were wrong: expected = %s, got =%s", testData, string(data))
 			}
 		})
@@ -274,7 +274,7 @@ func TestWriterNoPermissionFails(t *testing.T) {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(temp)
-	err = os.Chmod(temp, 0555)
+	err = os.Chmod(temp, 0o555)
 	if err != nil {
 		t.Fatal(err)
 	}

common/math/math.go

@@ -89,9 +89,9 @@ func InformationRatio(returnsRates, benchmarkRates []float64, averageValues, ave
 	if len(benchmarkRates) != len(returnsRates) {
 		return 0, errInformationBadLength
 	}
-	var diffs []float64
+	diffs := make([]float64, len(returnsRates))
 	for i := range returnsRates {
-		diffs = append(diffs, returnsRates[i]-benchmarkRates[i])
+		diffs[i] = returnsRates[i] - benchmarkRates[i]
 	}
 	stdDev, err := PopulationStandardDeviation(diffs)
 	if err != nil {
@@ -135,11 +135,11 @@ func SampleStandardDeviation(values []float64) (float64, error) {
 	if err != nil {
 		return 0, err
 	}
-	var superMean []float64
+	superMean := make([]float64, len(values))
 	var combined float64
 	for i := range values {
 		result := math.Pow(values[i]-mean, 2)
-		superMean = append(superMean, result)
+		superMean[i] = result
 		combined += result
 	}
 	avg := combined / (float64(len(superMean)) - 1)
@@ -232,9 +232,9 @@ func SharpeRatio(movementPerCandle []float64, riskFreeRatePerInterval, average f
 	if totalIntervals == 0 {
 		return 0, errZeroValue
 	}
-	var excessReturns []float64
+	excessReturns := make([]float64, len(movementPerCandle))
 	for i := range movementPerCandle {
-		excessReturns = append(excessReturns, movementPerCandle[i]-riskFreeRatePerInterval)
+		excessReturns[i] = movementPerCandle[i] - riskFreeRatePerInterval
 	}
 	standardDeviation, err := PopulationStandardDeviation(excessReturns)
 	if err != nil {
@@ -284,9 +284,9 @@ func DecimalInformationRatio(returnsRates, benchmarkRates []decimal.Decimal, ave
 	if len(benchmarkRates) != len(returnsRates) {
 		return decimal.Zero, errInformationBadLength
 	}
-	var diffs []decimal.Decimal
+	diffs := make([]decimal.Decimal, len(returnsRates))
 	for i := range returnsRates {
-		diffs = append(diffs, returnsRates[i].Sub(benchmarkRates[i]))
+		diffs[i] = returnsRates[i].Sub(benchmarkRates[i])
 	}
 	stdDev, err := DecimalPopulationStandardDeviation(diffs)
 	if err != nil && !errors.Is(err, ErrInexactConversion) {
@@ -339,11 +339,11 @@ func DecimalSampleStandardDeviation(values []decimal.Decimal) (decimal.Decimal,
 	if err != nil {
 		return decimal.Zero, err
 	}
-	var superMean []decimal.Decimal
+	superMean := make([]decimal.Decimal, len(values))
 	var combined decimal.Decimal
 	for i := range values {
 		pow := values[i].Sub(mean).Pow(decimal.NewFromInt(2))
-		superMean = append(superMean, pow)
+		superMean[i] = pow
 		combined.Add(pow)
 	}
 	avg := combined.Div(decimal.NewFromInt(int64(len(superMean))).Sub(decimal.NewFromInt(1)))
@@ -380,9 +380,7 @@ func DecimalGeometricMean(values []decimal.Decimal) (decimal.Decimal, error) {
 // DecimalPow is lovely because shopspring decimal cannot
 // handle ^0.x and instead returns 1
 func DecimalPow(x, y decimal.Decimal) decimal.Decimal {
-	fX, _ := x.Float64()
-	fY, _ := y.Float64()
-	pow := math.Pow(fX, fY)
+	pow := math.Pow(x.InexactFloat64(), y.InexactFloat64())
 	return decimal.NewFromFloat(pow)
 }
 
@@ -405,7 +403,7 @@ func DecimalFinancialGeometricMean(values []decimal.Decimal) (decimal.Decimal, e
 		// as we cannot have negative or zero value geometric numbers
 		// adding a 1 to the percentage movements allows for differentiation between
 		// negative numbers (eg -0.1 translates to 0.9) and positive numbers (eg 0.1 becomes 1.1)
-		modVal, _ := values[i].Add(decimal.NewFromInt(1)).Float64()
+		modVal := values[i].Add(decimal.NewFromInt(1)).InexactFloat64()
 		product *= modVal
 	}
 	prod := 1 / float64(len(values))
@@ -461,9 +459,9 @@ func DecimalSharpeRatio(movementPerCandle []decimal.Decimal, riskFreeRatePerInte
 	if totalIntervals.IsZero() {
 		return decimal.Zero, errZeroValue
 	}
-	var excessReturns []decimal.Decimal
+	excessReturns := make([]decimal.Decimal, len(movementPerCandle))
 	for i := range movementPerCandle {
-		excessReturns = append(excessReturns, movementPerCandle[i].Sub(riskFreeRatePerInterval))
+		excessReturns[i] = movementPerCandle[i].Sub(riskFreeRatePerInterval)
 	}
 	standardDeviation, err := DecimalPopulationStandardDeviation(excessReturns)
 	if err != nil && !errors.Is(err, ErrInexactConversion) {

common/math/math_test.go

@@ -184,9 +184,9 @@ func TestInformationRatio(t *testing.T) {
 		t.Error(avgComparison)
 	}
 
-	var eachDiff []float64
+	eachDiff := make([]float64, len(figures))
 	for i := range figures {
-		eachDiff = append(eachDiff, figures[i]-comparisonFigures[i])
+		eachDiff[i] = figures[i] - comparisonFigures[i]
 	}
 	stdDev, err := PopulationStandardDeviation(eachDiff)
 	if err != nil {
@@ -583,9 +583,9 @@ func TestDecimalInformationRatio(t *testing.T) {
 		t.Error(avgComparison)
 	}
 
-	var eachDiff []decimal.Decimal
+	eachDiff := make([]decimal.Decimal, len(figures))
 	for i := range figures {
-		eachDiff = append(eachDiff, figures[i].Sub(comparisonFigures[i]))
+		eachDiff[i] = figures[i].Sub(comparisonFigures[i])
 	}
 	stdDev, err := DecimalPopulationStandardDeviation(eachDiff)
 	if err != nil && !errors.Is(err, ErrInexactConversion) {
@@ -703,14 +703,13 @@ func TestDecimalStandardDeviation2(t *testing.T) {
 	if err != nil {
 		t.Error(err)
 	}
-	var superMean []decimal.Decimal
+	superMean := make([]decimal.Decimal, len(r))
 	for i := range r {
 		result := r[i].Sub(mean).Pow(decimal.NewFromInt(2))
-		superMean = append(superMean, result)
+		superMean[i] = result
 	}
 	superMeany := superMean[0].Add(superMean[1].Add(superMean[2].Add(superMean[3].Add(superMean[4].Add(superMean[5]))))).Div(decimal.NewFromInt(5))
-	fSuperMeany, _ := superMeany.Float64()
-	manualCalculation := decimal.NewFromFloat(math.Sqrt(fSuperMeany))
+	manualCalculation := decimal.NewFromFloat(math.Sqrt(superMeany.InexactFloat64()))
 	var codeCalcu decimal.Decimal
 	codeCalcu, err = DecimalSampleStandardDeviation(r)
 	if err != nil {