TODO.md

@@ -19,6 +19,8 @@ trial run of the finished image: https://git.eeqj.de/sneak/dnswatcher/issues/149
 
 # Completed Steps
 
+- 2026-10-02: a nameserver whose query for one record type failed while the
+  others answered with no records is `ok`, not `nodata` (closes #253).
 - 2026-10-02: a domain that does not exist is shown so, with no nameservers; no
   name gets a parent's nameservers when its own did not answer (closes #222).
 - 2026-10-02: the refused-query test sends one query to four operators' public

internal/resolver/iterative.go

@@ -941,7 +941,9 @@ func isTimeout(err error) bool {
 
 // classifyResponse sets the nameserver's status. One that answered no
 // record type has failed, and Error says why; one that answered some has
-// the status of those answers.
+// the status of those answers. It has no data only when every type
+// answered with no records: a type in FailedTypes may have records, so a
+// nameserver with one stays ok.
 func classifyResponse(resp *NameserverResponse, state queryState) {
 	switch {
 	case state.gotNXDomain && !state.hasRecords:
@@ -961,7 +963,8 @@ func classifyResponse(resp *NameserverResponse, state queryState) {
 	case state.gotReferral && !state.answered:
 		resp.Status = StatusError
 		resp.Error = "server returned a referral"
-	case !state.hasRecords && !state.gotNXDomain:
+	// An NXDOMAIN reply with no records was taken by the first case.
+	case !state.hasRecords && len(resp.FailedTypes) == 0:
 		resp.Status = StatusNoData
 	}
 }

internal/resolver/iterative_internal_test.go

@@ -11,60 +11,77 @@ import (
 )
 
 // TestClassifyResponse sets a nameserver's status from the results of
-// its queries, built here. One that answered some record types, even
+// its queries and the record types whose query failed, built here. One
-// with no records, has not failed when its query for another type got
+// that answered some record types, even with no records, has not failed
-// no usable reply, whatever the reason; one whose every query got none
+// when its query for another type got no usable reply, whatever the
-// has.
+// reason, and is ok, not nodata: that type may have records. One whose
+// every query got none has failed. Only one whose every type answered
+// with no records is nodata.
 func TestClassifyResponse(t *testing.T) {
 	t.Parallel()
 
 	tests := []struct {
-		name       string
+		name        string
-		results    queryState
+		results     queryState
-		wantStatus string
+		failedTypes []string
-		wantError  string
+		wantStatus  string
+		wantError   string
 	}{
+		{
+			"every type answered with no records",
+			queryState{answered: true},
+			nil,
+			StatusNoData, "",
+		},
 		{
 			"some types answered with no records, another timed out",
 			queryState{answered: true, gotTimeout: true},
-			StatusNoData, "",
+			[]string{"A"},
+			StatusOK, "",
 		},
 		{
 			"some types answered with no records, another got SERVFAIL",
 			queryState{
 				answered: true, gotErrorReply: true, errorReply: "SERVFAIL",
 			},
-			StatusNoData, "",
+			[]string{"A"},
+			StatusOK, "",
 		},
 		{
 			"some types answered with no records, another was refused",
 			queryState{answered: true, gotRefused: true},
-			StatusNoData, "",
+			[]string{"A"},
+			StatusOK, "",
 		},
 		{
 			"some types answered with no records, another got a network error",
 			queryState{answered: true, netErr: syscall.ECONNREFUSED},
-			StatusNoData, "",
+			[]string{"A"},
+			StatusOK, "",
 		},
 		{
 			"some types answered with no records, another's reply was " +
 				"truncated and its retry over TCP failed",
 			queryState{answered: true, netErr: ErrTruncated},
-			StatusNoData, "",
+			[]string{"TXT"},
+			StatusOK, "",
 		},
 		{
 			"some types answered with no records, another got a referral",
 			queryState{answered: true, gotReferral: true},
-			StatusNoData, "",
+			[]string{"A"},
+			StatusOK, "",
 		},
 		{
 			"every query timed out",
 			queryState{gotTimeout: true},
+			[]string{"A", "AAAA", "CNAME"},
 			StatusTimeout, "all queries timed out",
 		},
 		{
 			"every query got NOTIMP",
 			queryState{gotErrorReply: true, errorReply: "NOTIMP"},
+			[]string{"A", "AAAA", "CNAME"},
 			StatusError, "server returned NOTIMP",
 		},
 	}
@@ -73,11 +90,12 @@ func TestClassifyResponse(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 
-			resp := &NameserverResponse{Status: StatusOK}
+			resp := &NameserverResponse{Status: StatusOK, FailedTypes: tt.failedTypes}
 			classifyResponse(resp, tt.results)
 
 			assert.Equal(t, tt.wantStatus, resp.Status)
 			assert.Equal(t, tt.wantError, resp.Error)
+			assert.Equal(t, tt.failedTypes, resp.FailedTypes)
 		})
 	}
 }