lint: enable wastedassign linter (#7340)

.golangci.yml

@@ -13,6 +13,7 @@ linters:
     - unconvert
     - unused
     - usetesting
+    - wastedassign
     - whitespace
   exclusions:
     generated: lax

plugin/cache/handler.go

@@ -34,14 +34,13 @@ func (c *Cache) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg)
 	// in which upstream doesn't support DNSSEC, the two cache items will effectively be the same. Regardless, any
 	// DNSSEC RRs in the response are written to cache with the response.
 
-	ttl := 0
 	i := c.getIgnoreTTL(now, state, server)
 	if i == nil {
 		crr := &ResponseWriter{ResponseWriter: w, Cache: c, state: state, server: server, do: do, ad: ad, cd: cd,
 			nexcept: c.nexcept, pexcept: c.pexcept, wildcardFunc: wildcardFunc(ctx)}
 		return c.doRefresh(ctx, state, crr)
 	}
-	ttl = i.ttl(now)
+	ttl := i.ttl(now)
 	if ttl < 0 {
 		// serve stale behavior
 		if c.verifyStale {

plugin/dnstap/setup.go

@@ -25,7 +25,7 @@ func parseConfig(c *caddy.Controller) ([]*Dnstap, error) {
 			MultipleTcpWriteBuf: 1,
 			MultipleQueue:       1,
 		}
-		endpoint := ""
+
 		d.repl = replacer.New()
 
 		args := c.RemainingArgs()
@@ -34,7 +34,7 @@ func parseConfig(c *caddy.Controller) ([]*Dnstap, error) {
 			return nil, c.ArgErr()
 		}
 
-		endpoint = args[0]
+		endpoint := args[0]
 
 		if len(args) >= 3 {
 			d.MultipleTcpWriteBuf, _ = strconv.Atoi(args[2])

plugin/hosts/hostsfile.go

@@ -171,7 +171,7 @@ func (h *Hostsfile) parse(r io.Reader) *Map {
 			continue
 		}
 
-		family := 0
+		var family int
 		if addr.To4() != nil {
 			family = 1
 		} else {

plugin/kubernetes/kubernetes.go

@@ -379,7 +379,8 @@ func (k *Kubernetes) findPods(r recordRequest, zone string) (pods []msg.Service,
 	}
 
 	zonePath := msg.Path(zone, coredns)
-	ip := ""
+
+	var ip string
 	if strings.Count(podname, "-") == 3 && !strings.Contains(podname, "--") {
 		ip = strings.ReplaceAll(podname, "-", ".")
 	} else {

plugin/pkg/dnsutil/reverse.go

@@ -11,10 +11,8 @@ import (
 // 54.119.58.176.in-addr.arpa. becomes 176.58.119.54. If the conversion
 // fails the empty string is returned.
 func ExtractAddressFromReverse(reverseName string) string {
-	search := ""
-
 	f := reverse
-
+	var search string
 	switch {
 	case strings.HasSuffix(reverseName, IP4arpa):
 		search = strings.TrimSuffix(reverseName, IP4arpa)

plugin/pkg/proxy/connect.go

@@ -107,7 +107,7 @@ func (t *Transport) Dial(proto string) (*persistConn, bool, error) {
 func (p *Proxy) Connect(ctx context.Context, state request.Request, opts Options) (*dns.Msg, error) {
 	start := time.Now()
 
-	proto := ""
+	var proto string
 	switch {
 	case opts.ForceTCP: // TCP flag has precedence over UDP flag
 		proto = "tcp"