add golangci-lint linter (#5499)

plugin/pkg/cidr/cidr.go

@@ -38,7 +38,7 @@ func Split(n *net.IPNet) []string {
 func nets(network *net.IPNet, newPrefixLen int) []*net.IPNet {
 	prefixLen, _ := network.Mask.Size()
 	maxSubnets := int(math.Exp2(float64(newPrefixLen)) / math.Exp2(float64(prefixLen)))
-	nets := []*net.IPNet{{network.IP, net.CIDRMask(newPrefixLen, 8*len(network.IP))}}
+	nets := []*net.IPNet{{IP: network.IP, Mask: net.CIDRMask(newPrefixLen, 8*len(network.IP))}}
 
 	for i := 1; i < maxSubnets; i++ {
 		next, exceeds := cidr.NextSubnet(nets[len(nets)-1], newPrefixLen)

plugin/pkg/dnstest/multirecorder_test.go

@@ -19,7 +19,6 @@ func TestMultiWriteMsg(t *testing.T) {
 
 	if len(record.Msgs) != 2 {
 		t.Fatalf("Expected 2 messages to be written, but instead found %d\n", len(record.Msgs))
-
 	}
 	if record.Len != responseTestMsg.Len()*2 {
 		t.Fatalf("Expected the bytes written counter to be %d, but instead found %d\n", responseTestMsg.Len()*2, record.Len)

plugin/pkg/dnsutil/reverse_test.go

@@ -66,6 +66,5 @@ func TestIsReverse(t *testing.T) {
 		if got != tc.expected {
 			t.Errorf("Test %d, got %d, expected %d for %s", i, got, tc.expected, tc.name)
 		}
-
 	}
 }

plugin/pkg/parse/host.go

@@ -32,7 +32,6 @@ func stripZone(host string) string {
 func HostPortOrFile(s ...string) ([]string, error) {
 	var servers []string
 	for _, h := range s {
-
 		trans, host := Transport(h)
 
 		addr, _, err := net.SplitHostPort(host)

plugin/pkg/rand/rand.go

@@ -32,5 +32,4 @@ func (r *Rand) Perm(n int) []int {
 	v := r.r.Perm(n)
 	r.m.Unlock()
 	return v
-
 }

plugin/pkg/replacer/replacer.go

@@ -271,6 +271,7 @@ func (r replacer) Replace(ctx context.Context, state request.Request, rr *dnstes
 		}
 	}
 	s := string(b)
+	//nolint:staticcheck
 	bufPool.Put(b[:0])
 	return s
 }

plugin/pkg/replacer/replacer_test.go

@@ -276,7 +276,6 @@ func BenchmarkReplacer(b *testing.B) {
 }
 
 func BenchmarkReplacer_CommonLogFormat(b *testing.B) {
-
 	w := dnstest.NewRecorder(&test.ResponseWriter{})
 	r := new(dns.Msg)
 	r.SetQuestion("example.org.", dns.TypeHINFO)