all: use Go 1.22 range-over-int

Updates #11058

Change-Id: I35e7ef9b90e83cac04ca93fd964ad00ed5b48430
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

cmd/cloner/cloner.go

@@ -102,7 +102,7 @@ func gen(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named) {
 	writef("}")
 	writef("dst := new(%s)", name)
 	writef("*dst = *src")
-	for i := 0; i < t.NumFields(); i++ {
+	for i := range t.NumFields() {
 		fname := t.Field(i).Name()
 		ft := t.Field(i).Type()
 		if !codegen.ContainsPointers(ft) || codegen.HasNoClone(t.Tag(i)) {

cmd/k8s-operator/testutils_test.go

@@ -522,7 +522,7 @@ func expectEvents(t *testing.T, rec *record.FakeRecorder, wantsEvents []string)
 	t.Helper()
 	// Events are not expected to arrive in order.
 	seenEvents := make([]string, 0)
-	for i := 0; i < len(wantsEvents); i++ {
+	for range len(wantsEvents) {
 		timer := time.NewTimer(time.Second * 5)
 		defer timer.Stop()
 		select {

cmd/netlogfmt/main.go

@@ -314,7 +314,7 @@ func mustMakeNamesByAddr() map[netip.Addr]string {
 	seen := make(map[string]bool)
 	namesByAddr := make(map[netip.Addr]string)
 retry:
-	for i := 0; i < 10; i++ {
+	for i := range 10 {
 		clear(seen)
 		clear(namesByAddr)
 		for _, d := range m.Devices {
@@ -354,7 +354,7 @@ func fieldPrefix(s string, n int) string {
 }
 
 func appendRepeatByte(b []byte, c byte, n int) []byte {
-	for i := 0; i < n; i++ {
+	for range n {
 		b = append(b, c)
 	}
 	return b

cmd/proxy-to-grafana/proxy-to-grafana.go

@@ -88,7 +88,7 @@ func main() {
 
 		go func() {
 			// wait for tailscale to start before trying to fetch cert names
-			for i := 0; i < 60; i++ {
+			for range 60 {
 				st, err := localClient.Status(context.Background())
 				if err != nil {
 					log.Printf("error retrieving tailscale status; retrying: %v", err)

cmd/sniproxy/sniproxy_test.go

@@ -158,7 +158,7 @@ func TestSNIProxyWithNetmapConfig(t *testing.T) {
 		t.Fatal(err)
 	}
 	gotConfigured := false
-	for i := 0; i < 100; i++ {
+	for range 100 {
 		s, err := l.StatusWithoutPeers(ctx)
 		if err != nil {
 			t.Fatal(err)

cmd/tailscale/cli/cli_test.go

@@ -831,7 +831,7 @@ func TestPrefFlagMapping(t *testing.T) {
 	}
 
 	prefType := reflect.TypeFor[ipn.Prefs]()
-	for i := 0; i < prefType.NumField(); i++ {
+	for i := range prefType.NumField() {
 		prefName := prefType.Field(i).Name
 		if prefHasFlag[prefName] {
 			continue

cmd/tailscale/cli/network-lock.go

@@ -148,7 +148,7 @@ func runNetworkLockInit(ctx context.Context, args []string) error {
 	}
 
 	fmt.Printf("%d disablement secrets have been generated and are printed below. Take note of them now, they WILL NOT be shown again.\n", nlInitArgs.numDisablements)
-	for i := 0; i < nlInitArgs.numDisablements; i++ {
+	for range nlInitArgs.numDisablements {
 		var secret [32]byte
 		if _, err := rand.Read(secret[:]); err != nil {
 			return err

cmd/tailscale/cli/serve_legacy.go

@@ -387,7 +387,7 @@ func isProxyTarget(source string) bool {
 // allNumeric reports whether s only comprises of digits
 // and has at least one digit.
 func allNumeric(s string) bool {
-	for i := 0; i < len(s); i++ {
+	for i := range len(s) {
 		if s[i] < '0' || s[i] > '9' {
 			return false
 		}

cmd/testcontrol/testcontrol.go

@@ -29,7 +29,7 @@ func main() {
 		DERPMap:         derpMap,
 		ExplicitBaseURL: "http://127.0.0.1:9911",
 	}
-	for i := 0; i < *flagNFake; i++ {
+	for range *flagNFake {
 		control.AddFakeNode()
 	}
 	mux := http.NewServeMux()

cmd/viewer/viewer.go

@@ -149,7 +149,7 @@ func genView(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named, thi
 		}
 	}
 	writeTemplate("common")
-	for i := 0; i < t.NumFields(); i++ {
+	for i := range t.NumFields() {
 		f := t.Field(i)
 		fname := f.Name()
 		if !f.Exported() {
@@ -292,7 +292,7 @@ func genView(buf *bytes.Buffer, it *codegen.ImportTracker, typ *types.Named, thi
 		}
 		writeTemplate("unsupportedField")
 	}
-	for i := 0; i < typ.NumMethods(); i++ {
+	for i := range typ.NumMethods() {
 		f := typ.Method(i)
 		if !f.Exported() {
 			continue