fix: address code review issues on PR #9

- gofmt main.go to fix tab indentation in main() body
- stats.go ComputeSummary: return nil when Answers and ByType are empty
- dns/types.go: remove duplicate ParseQueryType (dead code)
- formatter.go: log hook errors to stderr when Debug > 0; add Debug to Config
- text.go referralID: remove redundant depth==0 branch
- text.go writeServers: remove version lookup placeholder string

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: multica-agent <github@multica.ai>

cmd/exploredns/main.go

@@ -203,6 +203,7 @@ ShowSummaryResults: cfg.ShowSummaryResults,
 		Verbose:            cfg.Verbose,
 		Quiet:              cfg.Quiet,
 		Color:              os.Getenv("NO_COLOR") == "",
+		Debug:              cfg.Debug,
 	}
 
 	ctx := context.Background()

internal/dns/query_test.go

@@ -328,4 +328,3 @@ func TestQueryNoTCPFallbackWhenDisabled(t *testing.T) {
 		t.Error("expected truncated response to be returned as-is")
 	}
 }
-

internal/dns/types.go

@@ -1,9 +1,6 @@
 package dns
 
 import (
-	"fmt"
-	"strings"
-
 	"github.com/miekg/dns"
 )
 
@@ -40,32 +37,6 @@ func QNameType(qtype uint16) string {
 	return dns.TypeToString[qtype]
 }
 
-func ParseQueryType(s string) (uint16, error) {
-	s = strings.ToUpper(strings.TrimSpace(s))
-	switch s {
-	case "A":
-		return TypeA, nil
-	case "AAAA":
-		return TypeAAAA, nil
-	case "NS":
-		return TypeNS, nil
-	case "CNAME":
-		return TypeCNAME, nil
-	case "MX":
-		return TypeMX, nil
-	case "TXT":
-		return TypeTXT, nil
-	case "SOA":
-		return TypeSOA, nil
-	case "PTR":
-		return TypePTR, nil
-	case "ANY":
-		return TypeANY, nil
-	default:
-		return 0, fmt.Errorf("invalid query type: %s", s)
-	}
-}
-
 func DefaultEDNS0UDPSize() int {
 	return 2048
 }

internal/output/formatter.go

@@ -1,6 +1,7 @@
 package output
 
 import (
+	"fmt"
 	"io"
 	"os"
 
@@ -28,6 +29,7 @@ type Config struct {
 	Verbose            bool
 	Quiet              bool
 	Color              bool
+	Debug              int
 }
 
 func DefaultConfig() *Config {
@@ -69,16 +71,21 @@ func AttachHooks(cfg *Config, formatter Formatter) *traverse.TraverserHooks {
 	if cfg == nil || formatter == nil {
 		return nil
 	}
+	logErr := func(context string, err error) {
+		if err != nil && cfg.Debug > 0 {
+			fmt.Fprintf(os.Stderr, "Debug: formatter %s: %v\n", context, err)
+		}
+	}
 	return &traverse.TraverserHooks{
 		OnEvent: func(event traverse.TraversalEvent) {
 			switch {
 			case event.IsResolve && cfg.ShowResolves:
-				_ = formatter.WriteResolve(event)
+				logErr("WriteResolve", formatter.WriteResolve(event))
 			case !event.IsResolve && cfg.ShowProgress:
-				_ = formatter.WriteProgress(event)
+				logErr("WriteProgress", formatter.WriteProgress(event))
 			}
 			if event.Stage == traverse.EventComplete && cfg.ShowAllStats {
-				_ = formatter.WriteResult(event.Result)
+				logErr("WriteResult", formatter.WriteResult(event.Result))
 			}
 		},
 	}

internal/output/stats.go

@@ -73,6 +73,9 @@ func ComputeSummary(results []traverse.TraversalResult) *SummaryStats {
 		return stats.Answers[i].RData < stats.Answers[j].RData
 	})
 
+	if len(stats.Answers) == 0 && len(stats.ByType) == 0 {
+		return nil
+	}
 	return stats
 }
 

internal/output/text.go

@@ -99,11 +99,7 @@ func (f *textFormatter) writeServers(results []traverse.TraversalResult) error {
 
 	for _, name := range names {
 		for _, ip := range servers[name] {
-			version := ""
-			if f.cfg.ShowVersions {
-				version = " (version lookup pending)"
-			}
-			if _, err := fmt.Fprintf(f.w, "%*s: %-15s%s\n", width, name, ip, version); err != nil {
+			if _, err := fmt.Fprintf(f.w, "%*s: %-15s\n", width, name, ip); err != nil {
 				return err
 			}
 		}
@@ -234,9 +230,6 @@ func referralID(ref *traverse.Referral) string {
 	if ref == nil {
 		return ""
 	}
-	if ref.Depth == 0 {
-		return "1"
-	}
 	return fmt.Sprintf("%d", ref.Depth+1)
 }