lint: enable intrange linter (#7331)

Enable intrange linter to enforce modern Go range syntax over
traditional for loops, by converting:

for i := 0; i < n; i++

to:

for i := range n

Adding type conversions where needed for compatibility
with existing uint64 parameters.

Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>

plugin/pkg/cache/cache.go

@@ -38,7 +38,7 @@ func New(size int) *Cache {
 	c := &Cache{}
 
 	// Initialize all the shards
-	for i := 0; i < shardSize; i++ {
+	for i := range shardSize {
 		c.shards[i] = newShard(ssize)
 	}
 	return c

plugin/pkg/cache/cache_test.go

@@ -13,10 +13,10 @@ func TestCacheAddAndGet(t *testing.T) {
 		t.Fatal("Failed to find inserted record")
 	}
 
-	for i := 0; i < N; i++ {
+	for i := range N {
 		c.Add(uint64(i), 1)
 	}
-	for i := 0; i < N; i++ {
+	for i := range N {
 		c.Add(uint64(i), 1)
 		if c.Len() != N {
 			t.Fatal("A item was unnecessarily evicted from the cache")
@@ -45,7 +45,7 @@ func TestCacheLen(t *testing.T) {
 
 func TestCacheSharding(t *testing.T) {
 	c := New(shardSize)
-	for i := 0; i < shardSize*2; i++ {
+	for i := range shardSize * 2 {
 		c.Add(uint64(i), 1)
 	}
 	for i, s := range c.shards {
@@ -58,7 +58,7 @@ func TestCacheSharding(t *testing.T) {
 func TestCacheWalk(t *testing.T) {
 	c := New(10)
 	exp := make([]int, 10*2)
-	for i := 0; i < 10*2; i++ {
+	for i := range 10 * 2 {
 		c.Add(uint64(i), 1)
 		exp[i] = 1
 	}
@@ -78,7 +78,7 @@ func BenchmarkCache(b *testing.B) {
 	b.ReportAllocs()
 
 	c := New(4)
-	for n := 0; n < b.N; n++ {
+	for range b.N {
 		c.Add(1, 1)
 		c.Get(1)
 	}

plugin/pkg/cache/shard_test.go

@@ -26,11 +26,11 @@ func TestAddEvict(t *testing.T) {
 	const size = 1024
 	s := newShard(size)
 
-	for i := uint64(0); i < size; i++ {
-		s.Add(i, 1)
+	for i := range size {
+		s.Add(uint64(i), 1)
 	}
-	for i := uint64(0); i < size; i++ {
-		s.Add(i, 1)
+	for i := range size {
+		s.Add(uint64(i), 1)
 		if s.Len() != size {
 			t.Fatal("A item was unnecessarily evicted from the cache")
 		}
@@ -86,7 +86,7 @@ func TestShardLenEvict(t *testing.T) {
 
 	// Make sure we don't accidentally evict an element when
 	// we the key is already stored.
-	for i := 0; i < 4; i++ {
+	for range 4 {
 		s.Add(5, 1)
 		if l := s.Len(); l != 4 {
 			t.Fatalf("Shard size should %d, got %d", 4, l)
@@ -96,12 +96,12 @@ func TestShardLenEvict(t *testing.T) {
 
 func TestShardEvictParallel(t *testing.T) {
 	s := newShard(shardSize)
-	for i := uint64(0); i < shardSize; i++ {
-		s.Add(i, struct{}{})
+	for i := range shardSize {
+		s.Add(uint64(i), struct{}{})
 	}
 	start := make(chan struct{})
 	var wg sync.WaitGroup
-	for i := 0; i < shardSize; i++ {
+	for range shardSize {
 		wg.Add(1)
 		go func() {
 			<-start
@@ -119,7 +119,7 @@ func TestShardEvictParallel(t *testing.T) {
 func BenchmarkShard(b *testing.B) {
 	s := newShard(shardSize)
 	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for i := range b.N {
 		k := uint64(i) % shardSize * 2
 		s.Add(k, 1)
 		s.Get(k)

plugin/pkg/cidr/cidr.go

@@ -71,7 +71,7 @@ func Reverse(nets []string) []string {
 		nearest := (bits - ones) + mod
 		offset := 0
 		var end bool
-		for i := 0; i < nearest/sizeDigit; i++ {
+		for range nearest / sizeDigit {
 			offset, end = dns.NextLabel(r, offset)
 			if end {
 				break

plugin/pkg/dnstest/server.go

@@ -28,7 +28,7 @@ func NewServer(f dns.HandlerFunc) *Server {
 	s1 := &dns.Server{} // udp
 	s2 := &dns.Server{} // tcp
 
-	for i := 0; i < 5; i++ { // 5 attempts
+	for range 5 { // 5 attempts
 		s2.Listener, _ = reuseport.Listen("tcp", ":0")
 		if s2.Listener == nil {
 			continue

plugin/pkg/dnsutil/reverse.go

@@ -43,7 +43,7 @@ func IsReverse(name string) int {
 }
 
 func reverse(slice []string) string {
-	for i := 0; i < len(slice)/2; i++ {
+	for i := range len(slice) / 2 {
 		j := len(slice) - i - 1
 		slice[i], slice[j] = slice[j], slice[i]
 	}
@@ -58,12 +58,12 @@ func reverse(slice []string) string {
 // b.a.9.8.7.6.5.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2
 // is reversed to 2001:db8::567:89ab
 func reverse6(slice []string) string {
-	for i := 0; i < len(slice)/2; i++ {
+	for i := range len(slice) / 2 {
 		j := len(slice) - i - 1
 		slice[i], slice[j] = slice[j], slice[i]
 	}
 	slice6 := []string{}
-	for i := 0; i < len(slice)/4; i++ {
+	for i := range len(slice) / 4 {
 		slice6 = append(slice6, strings.Join(slice[i*4:i*4+4], ""))
 	}
 	ip := net.ParseIP(strings.Join(slice6, ":")).To16()

plugin/pkg/dnsutil/ttl_test.go

@@ -63,7 +63,7 @@ func BenchmarkMinimalTTL(b *testing.B) {
 	mt, _ := response.Typify(m, utc)
 
 	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for range b.N {
 		dur := MinimalTTL(m, mt)
 		if dur != 1000*time.Second {
 			b.Fatalf("Wrong MinimalTTL %d, expected %d", dur, 1000*time.Second)

plugin/pkg/proxy/connect_test.go

@@ -242,7 +242,7 @@ func TestDial_MultipleCallsAfterStop(t *testing.T) {
 	tr.Stop()
 	time.Sleep(50 * time.Millisecond)
 
-	for i := 0; i < 3; i++ {
+	for i := range 3 {
 		_, _, err := tr.Dial("udp")
 		if err == nil {
 			t.Errorf("Attempt %d: %s: %s", i+1, testMsgExpectedError, testMsgUnexpectedNilError)

plugin/pkg/rand/rand_test.go

@@ -47,7 +47,7 @@ func TestIntDeterministic(t *testing.T) {
 	r2 := New(seed)
 
 	// They should produce the same sequence
-	for i := 0; i < 10; i++ {
+	for i := range 10 {
 		val1 := r1.Int()
 		val2 := r2.Int()
 		if val1 != val2 {
@@ -123,11 +123,11 @@ func TestConcurrentAccess(t *testing.T) {
 	errors := make(chan error, numGoroutines*numOperations)
 
 	// Test concurrent Int() calls
-	for i := 0; i < numGoroutines; i++ {
+	for range numGoroutines {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
-			for j := 0; j < numOperations; j++ {
+			for range numOperations {
 				val := r.Int()
 				if val < 0 {
 					errors <- nil
@@ -137,11 +137,11 @@ func TestConcurrentAccess(t *testing.T) {
 	}
 
 	// Test concurrent Perm() calls
-	for i := 0; i < numGoroutines; i++ {
+	for range numGoroutines {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
-			for j := 0; j < numOperations; j++ {
+			for range numOperations {
 				perm := r.Perm(5)
 				if len(perm) != 5 {
 					errors <- nil
@@ -172,11 +172,11 @@ func TestConcurrentMixedOperations(t *testing.T) {
 	errors := make(chan error, numGoroutines*numOperations)
 
 	// Mix of Int() and Perm() operations running concurrently
-	for i := 0; i < numGoroutines; i++ {
+	for i := range numGoroutines {
 		wg.Add(1)
 		go func(id int) {
 			defer wg.Done()
-			for j := 0; j < numOperations; j++ {
+			for j := range numOperations {
 				if j%2 == 0 {
 					val := r.Int()
 					if val < 0 {

plugin/pkg/replacer/replacer_test.go

@@ -276,7 +276,7 @@ func BenchmarkReplacer(b *testing.B) {
 	b.ReportAllocs()
 
 	replacer := New()
-	for i := 0; i < b.N; i++ {
+	for range b.N {
 		replacer.Replace(context.TODO(), state, nil, "{type} {name} {size}")
 	}
 }
@@ -297,13 +297,13 @@ func BenchmarkReplacer_CommonLogFormat(b *testing.B) {
 
 	b.ResetTimer()
 	b.ReportAllocs()
-	for i := 0; i < b.N; i++ {
+	for range b.N {
 		replacer.Replace(ctxt, state, w, CommonLogFormat)
 	}
 }
 
 func BenchmarkParseFormat(b *testing.B) {
-	for i := 0; i < b.N; i++ {
+	for range b.N {
 		parseFormat(CommonLogFormat)
 	}
 }

plugin/pkg/singleflight/singleflight_test.go

@@ -63,7 +63,7 @@ func TestDoDupSuppress(t *testing.T) {
 
 	const n = 10
 	var wg sync.WaitGroup
-	for i := 0; i < n; i++ {
+	for range n {
 		wg.Add(1)
 		go func() {
 			v, err := g.Do(1, fn)