fix(resolvers): stop search-list iteration on NODATA responses

When search domains are configured (e.g., dnsmasq `domain=le`), doggo
appended search suffixes even when the original query got a valid NODATA
response (NOERROR with no answers). This caused spurious `. SOA ...
NXDOMAIN` results in the output.

The search-list loop now also breaks when the DNS response Rcode is
NOERROR (success), even if there are no answer records. NOERROR means
the name exists but has no records of the requested type — that's a
definitive answer, not a reason to try search suffixes.

Fixes #234

Author: mr-karan

pkg/resolvers/classic.go

@@ -119,7 +119,7 @@ func (r *ClassicResolver) query(ctx context.Context, question dns.Question, flag
 		rsp.Additional = output.Additional
 		rsp.Edns = output.Edns
 
-		if len(output.Answers) > 0 {
+		if len(output.Answers) > 0 || in.Rcode == dns.RcodeSuccess {
 			// Stop iterating the searchlist.
 			break
 		}

pkg/resolvers/dnscrypt.go

@@ -100,7 +100,7 @@ func (r *DNSCryptResolver) query(ctx context.Context, question dns.Question, fla
 			rsp.Additional = output.Additional
 			rsp.Edns = output.Edns
 
-			if len(output.Answers) > 0 {
+			if len(output.Answers) > 0 || in.Rcode == dns.RcodeSuccess {
 				// stop iterating the searchlist.
 				return rsp, nil
 			}

pkg/resolvers/doh.go

@@ -135,7 +135,7 @@ func (r *DOHResolver) query(ctx context.Context, question dns.Question, flags Qu
 		rsp.Additional = output.Additional
 		rsp.Edns = output.Edns
 
-		if len(output.Answers) > 0 {
+		if len(output.Answers) > 0 || msg.Rcode == dns.RcodeSuccess {
 			// stop iterating the searchlist.
 			break
 		}

pkg/resolvers/doq.go

@@ -168,7 +168,7 @@ func (r *DOQResolver) query(ctx context.Context, question dns.Question, flags Qu
 		rsp.Additional = output.Additional
 		rsp.Edns = output.Edns
 
-		if len(output.Answers) > 0 {
+		if len(output.Answers) > 0 || msg.Rcode == dns.RcodeSuccess {
 			// stop iterating the searchlist.
 			break
 		}