Apply go fix modernizations

config/config.go

@@ -164,17 +164,17 @@ func (a *FromAddr) parse(s string) error {
 }
 
 func parseChannelRange(spec string, start, end *int) error {
-	if idx := strings.Index(spec, "-"); idx != -1 {
-		s, err := strconv.Atoi(spec[:idx])
+	if before, after, ok := strings.Cut(spec, "-"); ok {
+		s, err := strconv.Atoi(before)
 		if err != nil {
 			return fmt.Errorf("invalid channel start: %w", err)
 		}
 		*start = s
 
-		if spec[idx+1:] == "" {
+		if after == "" {
 			*end = 512
 		} else {
-			e, err := strconv.Atoi(spec[idx+1:])
+			e, err := strconv.Atoi(after)
 			if err != nil {
 				return fmt.Errorf("invalid channel end: %w", err)
 			}
@@ -351,11 +351,11 @@ func Load(path string) (*Config, error) {
 
 // NormalizedMapping is a processed mapping ready for the remapper
 type NormalizedMapping struct {
-	From       Universe
-	FromChan   int // 0-indexed
-	To         Universe
-	ToChan     int // 0-indexed
-	Count      int
+	From     Universe
+	FromChan int // 0-indexed
+	To       Universe
+	ToChan   int // 0-indexed
+	Count    int
 }
 
 // Normalize converts config mappings to normalized form (0-indexed channels)

main.go

@@ -14,10 +14,10 @@ import (
 	"syscall"
 	"time"
 
-	"github.com/gopatchy/artnet"
 	"github.com/gopatchy/artmap/config"
 	"github.com/gopatchy/artmap/remap"
 	"github.com/gopatchy/artmap/senders"
+	"github.com/gopatchy/artnet"
 	"github.com/gopatchy/sacn"
 )
 
@@ -87,7 +87,7 @@ func main() {
 		if *artnetBroadcast == "auto" {
 			broadcasts = detectBroadcastAddrs()
 		} else {
-			for _, addrStr := range strings.Split(*artnetBroadcast, ",") {
+			for addrStr := range strings.SplitSeq(*artnetBroadcast, ",") {
 				addrStr = strings.TrimSpace(addrStr)
 				addr, err := parseTargetAddr(addrStr, artnet.Port)
 				if err != nil {
@@ -182,7 +182,7 @@ func main() {
 		if err != nil {
 			log.Fatalf("[sacn] failed to create receiver: %v", err)
 		}
-		receiver.SetHandler(func(src *net.UDPAddr, pkt interface{}) {
+		receiver.SetHandler(func(src *net.UDPAddr, pkt any) {
 			if data, ok := pkt.(*sacn.DataPacket); ok {
 				app.HandleSACN(src, data)
 			}
@@ -489,7 +489,7 @@ func detectLocalInterface(broadcast net.IP) (net.IP, net.HardwareAddr) {
 			}
 
 			bcast := make(net.IP, 4)
-			for i := 0; i < 4; i++ {
+			for i := range 4 {
 				bcast[i] = ip4[i] | ^mask[i]
 			}
 
@@ -540,7 +540,7 @@ func detectBroadcastAddrs() []*net.UDPAddr {
 			}
 
 			broadcast := make(net.IP, 4)
-			for i := 0; i < 4; i++ {
+			for i := range 4 {
 				broadcast[i] = ip4[i] | ^mask[i]
 			}
 

remap/fuzz_test.go

@@ -52,7 +52,7 @@ func FuzzRemap(f *testing.F) {
 			t.Fatalf("expected 1 output, got %d", len(outputs))
 		}
 
-		for i := 0; i < count; i++ {
+		for i := range count {
 			srcIdx := fromChan + i
 			dstIdx := toChan + i
 			if outputs[0].Data[dstIdx] != srcData[srcIdx] {
@@ -94,13 +94,13 @@ func FuzzRemapMultipleMappings(f *testing.F) {
 
 		for _, out := range outputs {
 			if out.Universe == dstU1 {
-				for i := 0; i < 256; i++ {
+				for i := range 256 {
 					if out.Data[i] != srcData[i] {
 						t.Fatalf("dstU1 mismatch at %d", i)
 					}
 				}
 			} else if out.Universe == dstU2 {
-				for i := 0; i < 256; i++ {
+				for i := range 256 {
 					if out.Data[i] != srcData[256+i] {
 						t.Fatalf("dstU2 mismatch at %d", i)
 					}