lint(revive): fix unnecessary-stmt violations (#7978)

.golangci.yml

@@ -99,7 +99,6 @@ linters:
           disabled: true
 
         - name: unnecessary-stmt
-          disabled: true
 
         - name: unreachable-code
           disabled: true

plugin/loadbalance/loadbalance.go

@@ -65,7 +65,6 @@ func roundRobin(in []dns.RR) []dns.RR {
 func roundRobinShuffle(records []dns.RR) {
 	switch l := len(records); l {
 	case 0, 1:
-		break
 	case 2:
 		if dns.Id()%2 == 0 {
 			records[0], records[1] = records[1], records[0]

plugin/ready/setup.go

@@ -90,8 +90,7 @@ func parse(c *caddy.Controller) (string, monitorType, error) {
 		}
 
 		for c.NextBlock() {
-			switch c.Val() {
+			if c.Val() == "monitor" {
-			case "monitor":
 				args := c.RemainingArgs()
 				if len(args) != 1 {
 					return "", "", c.ArgErr()

plugin/rewrite/cname_target.go

@@ -69,12 +69,18 @@ func (r *cnameTargetRule) getFromAndToTarget(inputCName string) (from string, to
 
 func (r *cnameTargetRuleWithReqState) RewriteResponse(res *dns.Msg, rr dns.RR) {
 	// logic to rewrite the cname target of dns response
-	switch rr.Header().Rrtype {
+	if rr.Header().Rrtype != dns.TypeCNAME {
-	case dns.TypeCNAME:
+		return
+	}
 	// rename the target of the cname response
-		if cname, ok := rr.(*dns.CNAME); ok {
+	cname, ok := rr.(*dns.CNAME)
+	if !ok {
+		return
+	}
 	fromTarget, toTarget := r.rule.getFromAndToTarget(cname.Target)
-			if cname.Target == fromTarget {
+	if cname.Target != fromTarget {
+		return
+	}
 	// create upstream request with the new target with the same qtype
 	r.state.Req.Question[0].Name = toTarget
 	// upRes can be nil if the internal query path didn't write a response
@@ -111,9 +117,6 @@ func (r *cnameTargetRuleWithReqState) RewriteResponse(res *dns.Msg, rr dns.RR) {
 	// and it will be impossible to resolve the full response
 	res.Truncated = upRes.Truncated
 }
-		}
-	}
-}
 
 func newCNAMERule(nextAction string, args ...string) (Rule, error) {
 	var rewriteType string

plugin/sign/signer.go

@@ -133,8 +133,7 @@ func resign(rd io.Reader, now time.Time) (why error) {
 	i := 0
 
 	for rr, ok := zp.Next(); ok; rr, ok = zp.Next() {
-		switch x := rr.(type) {
+		if x, ok := rr.(*dns.RRSIG); ok {
-		case *dns.RRSIG:
 			if x.TypeCovered != dns.TypeSOA {
 				continue
 			}