Fix CNAME and glue record behavior

TODO.txt

@@ -1,3 +1,4 @@
+- Refactor bad testdata into bad/ dir
 - CNAME resolution
 - Ensure NS records don't point inward (will require changes to unrelated tests)
 - Alias values via `!alias <hostname> <type> [index, default 0]`

yamlzone.go

@@ -123,10 +123,11 @@ func (z *Zone) Validate(name string, soa *NamedRecord, ns *[]Record) error {
 		}
 		for subname, subzone := range z.Subzones {
 			// This populates z.GlueRecords directly
-			err := subzone.GetGlueRecords(concatName(name, subname), nameserversMap)
+			glueRecords, err := subzone.GetGlueRecords(concatName(name, subname), nameserversMap)
 			if err != nil {
 				return err
 			}
+			z.GlueRecords = append(z.GlueRecords, glueRecords...)
 		}
 		return nil
 	} else {
@@ -136,7 +137,6 @@ func (z *Zone) Validate(name string, soa *NamedRecord, ns *[]Record) error {
 	}
 
 	// Either we're outside a zone, at a zone apex, or at a non-delegated subzone
-
 	for subname, subzone := range z.Subzones {
 		if err := subzone.Validate(concatName(name, subname), soa, ns); err != nil {
 			return err
@@ -145,26 +145,30 @@ func (z *Zone) Validate(name string, soa *NamedRecord, ns *[]Record) error {
 	return nil
 }
 
-func (z *Zone) GetGlueRecords(name string, nameserversMap map[string]bool) error {
+func (z *Zone) GetGlueRecords(name string, nameserversMap map[string]bool) ([]NamedRecord, error) {
 	// If the domain is not a nameserver, it must have no records
 	if _, ok := nameserversMap[strings.TrimSuffix(name, ".")]; !ok {
 		if len(z.Records) > 0 {
-			return fmt.Errorf("%s: non-glue records found under delegation point: %v", name, z.Records)
+			return nil, fmt.Errorf("%s: non-glue records found under delegation point: %v", name, z.Records)
 		}
 	}
 	// Any records under a delegation point must be glue records
+	glueRecords := []NamedRecord{}
 	for _, record := range z.Records {
 		if !(record.Type == "A" || record.Type == "AAAA") {
-			return fmt.Errorf("%s: non-glue record found under delegation point: %v", name, record)
+			return nil, fmt.Errorf("%s: non-glue record found under delegation point: %v", name, record)
 		}
-		z.GlueRecords = append(z.GlueRecords, NamedRecord{Name: name, Record: record})
+		glueRecords = append(glueRecords, NamedRecord{Name: name, Record: record})
 	}
 	for subname, subzone := range z.Subzones {
-		if err := subzone.GetGlueRecords(concatName(name, subname), nameserversMap); err != nil {
-			return err
+		var subGlueRecords []NamedRecord
+		var err error
+		if subGlueRecords, err = subzone.GetGlueRecords(concatName(name, subname), nameserversMap); err != nil {
+			return nil, err
 		}
+		glueRecords = append(glueRecords, subGlueRecords...)
 	}
-	return nil
+	return glueRecords, nil
 }
 
 func (r *Record) UnmarshalYAML(ctx context.Context, data []byte) error {
@@ -299,6 +303,11 @@ func (z *Zone) LookupType(name string, recordType string) (LookupResult, bool) {
 		} else {
 			z = sz
 		}
+		if len(z.Records) > 0 && z.Records[0].Type == "CNAME" {
+			// Return CNAME
+			res.Answer = []NamedRecord{{Name: name, Record: z.Records[0]}}
+			return res, true
+		}
 		if z.IsDelegationPoint {
 			// Retrieve glue records from cache, whether referral or NS query
 			res.Extra = append(res.Extra, z.GlueRecords...)

yamlzone_test.go

@@ -181,8 +181,15 @@ func TestFullZone(t *testing.T) {
 		assertRecord(t, res.Answer[0].Record, "CNAME", 3600, "example.com")
 	})
 
-	t.Run("Lookup www.example.com TXT", func(t *testing.T) {
-		res, ok := zFull.LookupType("www.example.com", "TXT")
+	t.Run("LookupType www.example.com A", func(t *testing.T) {
+		res, ok := zFull.LookupType("www.example.com", "CNAME")
+		assertOk(t, ok)
+		assertRecordCount(t, res, 1)
+		assertRecord(t, res.Answer[0].Record, "CNAME", 3600, "example.com")
+	})
+
+	t.Run("LookupType mail.example.com TXT", func(t *testing.T) {
+		res, ok := zFull.LookupType("mail.example.com", "TXT")
 		assertOk(t, ok)
 		assertRecordCount(t, res, 0)
 	})