CI/build: Update Go version, linters and fix minor issues (#1612)

* CI/build: Update Go version, linters and fix minor issues

* linters: Add intrange, copyloopvar, additional go vet linters to match gopls and fix issues

engine/apiserver.go

@@ -591,7 +591,7 @@ func (c *websocketClient) write() {
 
 		// Add queued chat messages to the current websocket message
 		n := len(c.Send)
-		for i := 0; i < n; i++ {
+		for range n {
 			_, err = w.Write(<-c.Send)
 			if err != nil {
 				log.Errorln(log.APIServerMgr, err)

engine/datahistory_manager.go

@@ -958,7 +958,7 @@ func (m *DataHistoryManager) validateCandles(job *DataHistoryJob, exch exchange.
 	}
 	var validationIssues []string
 	multiplier := int64(1)
-	for i := int64(0); i < job.DecimalPlaceComparison; i++ {
+	for range job.DecimalPlaceComparison {
 		multiplier *= 10
 	}
 	for i := range apiCandles.Candles {

engine/datahistory_manager_test.go

@@ -1410,7 +1410,7 @@ func TestSaveCandlesInBatches(t *testing.T) {
 		t.Errorf("received %v expected %v", err, nil)
 	}
 
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		candles.Candles = append(candles.Candles, kline.Candle{
 			Volume: float64(i),
 		})
@@ -1524,17 +1524,17 @@ func dataHistoryTraderLoader(exch, a, base, quote string, start, _ time.Time) ([
 func dataHistoryCandleLoader(exch string, cp currency.Pair, a asset.Item, interval kline.Interval, start, end time.Time) (*kline.Item, error) {
 	start = start.Truncate(interval.Duration())
 	end = end.Truncate(interval.Duration())
-	var candles []kline.Candle
 	intervals := end.Sub(start) / interval.Duration()
-	for i := 0; i < int(intervals); i++ {
-		candles = append(candles, kline.Candle{
+	candles := make([]kline.Candle, int(intervals))
+	for x := range int(intervals) {
+		candles[x] = kline.Candle{
 			Time:   start,
 			Open:   1,
 			High:   10,
 			Low:    1,
 			Close:  4,
 			Volume: 8,
-		})
+		}
 		start = start.Add(interval.Duration())
 	}
 	return &kline.Item{

engine/engine.go

@@ -272,7 +272,7 @@ func (s *Settings) PrintLoadedSettings() {
 	gctlog.Debugln(gctlog.Global)
 	gctlog.Debugf(gctlog.Global, "ENGINE SETTINGS")
 	settings := reflect.ValueOf(*s)
-	for x := 0; x < settings.NumField(); x++ {
+	for x := range settings.NumField() {
 		field := settings.Field(x)
 		if field.Kind() != reflect.Struct {
 			continue
@@ -280,7 +280,7 @@ func (s *Settings) PrintLoadedSettings() {
 
 		fieldName := field.Type().Name()
 		gctlog.Debugln(gctlog.Global, "- "+common.AddPaddingOnUpperCase(fieldName)+":")
-		for y := 0; y < field.NumField(); y++ {
+		for y := range field.NumField() {
 			indvSetting := field.Field(y)
 			indvName := field.Type().Field(y).Name
 			if indvSetting.Kind() == reflect.String && indvSetting.IsZero() {

engine/engine_test.go

@@ -65,7 +65,6 @@ func TestLoadConfigWithSettings(t *testing.T) {
 		},
 	}
 	for _, tt := range tests {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			// prepare the 'flags'
 			flagSet := make(map[string]bool)

engine/helpers_test.go

@@ -216,7 +216,6 @@ func TestSetSubsystem(t *testing.T) { //nolint // TO-DO: Fix race t.Parallel() u
 	}
 
 	for _, tt := range testCases {
-		tt := tt
 		t.Run(tt.Subsystem, func(t *testing.T) {
 			t.Parallel()
 			err := tt.Engine.SetSubsystem(tt.Subsystem, true)

engine/ntp_manager.go

@@ -52,7 +52,7 @@ func (m *ntpManager) Start() error {
 		// Sometimes the NTP client can have transient issues due to UDP, try
 		// the default retry limits before giving up
 	check:
-		for i := 0; i < m.retryLimit; i++ {
+		for i := range m.retryLimit {
 			err := m.processTime()
 			switch err {
 			case nil:

engine/rpcserver.go

@@ -1758,7 +1758,7 @@ func (s *RPCServer) WithdrawCryptocurrencyFunds(ctx context.Context, r *gctrpc.W
 
 	if exchCfg.API.Credentials.PIN != "" {
 		pinCode, errPin := strconv.ParseInt(exchCfg.API.Credentials.PIN, 10, 64)
-		if err != nil {
+		if errPin != nil {
 			return nil, errPin
 		}
 		req.PIN = pinCode
@@ -1815,12 +1815,12 @@ func (s *RPCServer) WithdrawFiatFunds(ctx context.Context, r *gctrpc.WithdrawFia
 
 	if exchCfg.API.Credentials.OTPSecret != "" {
 		code, errOTP := totp.GenerateCode(exchCfg.API.Credentials.OTPSecret, time.Now())
-		if err != nil {
+		if errOTP != nil {
 			return nil, errOTP
 		}
 
 		codeNum, errOTP := strconv.ParseInt(code, 10, 64)
-		if err != nil {
+		if errOTP != nil {
 			return nil, errOTP
 		}
 		req.OneTimePassword = codeNum
@@ -1828,7 +1828,7 @@ func (s *RPCServer) WithdrawFiatFunds(ctx context.Context, r *gctrpc.WithdrawFia
 
 	if exchCfg.API.Credentials.PIN != "" {
 		pinCode, errPIN := strconv.ParseInt(exchCfg.API.Credentials.PIN, 10, 64)
-		if err != nil {
+		if errPIN != nil {
 			return nil, errPIN
 		}
 		req.PIN = pinCode
@@ -4938,7 +4938,7 @@ func (s *RPCServer) GetCollateral(ctx context.Context, r *gctrpc.GetCollateralRe
 			}
 			tick, err = exch.FetchTicker(ctx, tickerCurr, asset.Spot)
 			if err != nil {
-				log.Errorf(log.GRPCSys, fmt.Sprintf("GetCollateral offline calculation error via FetchTicker %s %s", exch.GetName(), err))
+				log.Errorf(log.GRPCSys, "GetCollateral offline calculation error via FetchTicker %s %s", exch.GetName(), err)
 				continue
 			}
 			if tick.Last == 0 {

engine/rpcserver_test.go

@@ -241,7 +241,7 @@ func (f fExchange) GetHistoricCandles(_ context.Context, p currency.Pair, a asse
 
 func generateCandles(amount int, timeStart time.Time, interval kline.Interval) []kline.Candle {
 	candy := make([]kline.Candle, amount)
-	for x := 0; x < amount; x++ {
+	for x := range amount {
 		candy[x] = kline.Candle{
 			Time:   timeStart,
 			Open:   1337,
@@ -1630,8 +1630,8 @@ func TestCheckVars(t *testing.T) {
 func TestParseEvents(t *testing.T) {
 	t.Parallel()
 	var exchangeName = "Binance"
-	var testData []*withdraw.Response
-	for x := 0; x < 5; x++ {
+	testData := make([]*withdraw.Response, 5)
+	for x := range 5 {
 		test := fmt.Sprintf("test-%v", x)
 		resp := &withdraw.Response{
 			ID: withdraw.DryRunID,
@@ -1668,13 +1668,13 @@ func TestParseEvents(t *testing.T) {
 			resp.RequestDetails.Crypto.FeeAmount = 0
 			resp.RequestDetails.Crypto.AddressTag = test
 		}
-		testData = append(testData, resp)
+		testData[x] = resp
 	}
 	v := parseMultipleEvents(testData)
 	if reflect.TypeOf(v).String() != "*gctrpc.WithdrawalEventsByExchangeResponse" {
 		t.Fatal("expected type to be *gctrpc.WithdrawalEventsByExchangeResponse")
 	}
-	if testData == nil || len(testData) < 2 {
+	if len(testData) < 2 {
 		t.Fatal("expected at least 2")
 	}
 
@@ -4214,7 +4214,6 @@ func TestStartRPCRESTProxy(t *testing.T) {
 		{"Invalid username but valid password", "bonk", "Sup3rdup3rS3cr3t"},
 		{"Invalid username and password despite glorious credentials", "bonk", "wif"},
 	} {
-		creds := creds
 		t.Run(creds.testDescription, func(t *testing.T) {
 			t.Parallel()
 
@@ -4259,7 +4258,7 @@ func TestRPCProxyAuthClient(t *testing.T) {
 	dummyHandler := http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 		w.WriteHeader(http.StatusOK)
 		_, err := w.Write([]byte("MEOW"))
-		require.NoError(t, err, "Write should not error")
+		assert.NoError(t, err, "Write should not error")
 	})
 
 	handler := s.authClient(dummyHandler)
@@ -4274,7 +4273,6 @@ func TestRPCProxyAuthClient(t *testing.T) {
 		{"Invalid username but valid password", "bonk", "Sup3rdup3rS3cr3t"},
 		{"Invalid username and password despite glorious credentials", "bonk", "wif"},
 	} {
-		creds := creds
 		t.Run(creds.testDescription, func(t *testing.T) {
 			t.Parallel()
 

engine/sync_manager.go

@@ -229,7 +229,7 @@ func (m *SyncManager) Start() error {
 		return nil
 	}
 
-	for i := 0; i < m.config.NumWorkers; i++ {
+	for range m.config.NumWorkers {
 		go m.worker()
 	}
 	m.initSyncWG.Done()