fix(Query): Fix incorrect RDF response. (#7017)

* remove <X> <uid> <X> type of triplets from the output

* fix output for recurse queries

* fix for recurse queries

* fix test

* add Test for ignoring uid

* minor modification

* fix solution for recurse

query/outputrdf.go

@@ -75,6 +75,19 @@ func (b *rdfBuilder) castToRDF(sg *SubGraph) error {
 
 // rdfForSubgraph generates RDF and appends to the output parameter.
 func (b *rdfBuilder) rdfForSubgraph(sg *SubGraph) error {
+	// handle the case of recurse queries
+	// Do not generate RDF if all the children of sg null uidMatrix
+	nonNullChild := false
+	for _, ch := range sg.Children {
+		if len(ch.uidMatrix) != 0 {
+			nonNullChild = true
+		}
+	}
+
+	if len(sg.Children) > 0 && !nonNullChild {
+		return nil
+	}
+
 	for i, uid := range sg.SrcUIDs.Uids {
 		if sg.Params.IgnoreResult {
 			// Skip ignored values.
@@ -101,7 +114,7 @@ func (b *rdfBuilder) rdfForSubgraph(sg *SubGraph) error {
 		case len(sg.counts) > 0:
 			// Add count rdf.
 			b.rdfForCount(uid, sg.counts[i], sg)
-		case i < len(sg.uidMatrix) && len(sg.uidMatrix[i].Uids) != 0:
+		case i < len(sg.uidMatrix) && len(sg.uidMatrix[i].Uids) != 0 && len(sg.Children) > 0:
 			// Add posting list relation.
 			b.rdfForUIDList(uid, sg.uidMatrix[i], sg)
 		case i < len(sg.valueMatrix):
@@ -154,11 +167,8 @@ func (b *rdfBuilder) rdfForUIDList(subject uint64, list *pb.List, sg *SubGraph)
 }
 
 // rdfForValueList returns rdf for the value list.
+// Ignore RDF's for the attirbute `uid`.
 func (b *rdfBuilder) rdfForValueList(subject uint64, valueList *pb.ValueList, attr string) {
-	if attr == "uid" {
-		b.writeRDF(subject, []byte(attr), x.ToHex(subject, true))
-		return
-	}
 	for _, destValue := range valueList.Values {
 		val, err := convertWithBestEffort(destValue, attr)
 		if err != nil {

query/rdf_result_test.go

@@ -111,6 +111,38 @@ func TestRDFIngoreReflex(t *testing.T) {
 		"ignorereflex directive is not supported in the rdf output format")
 }
 
+func TestRDFRecurse(t *testing.T) {
+	query := `
+	{
+		me(func: anyofterms(name, "Michonne Rick Daryl")) @recurse(depth: 1, loop: true) {
+			name
+			friend
+		}
+	}`
+	rdf, err := processQueryRDF(context.Background(), t, query)
+	require.NoError(t, err)
+	require.Equal(t, rdf, `<0x1> <name> "Michonne" .
+<0x17> <name> "Rick Grimes" .
+<0x19> <name> "Daryl Dixon" .
+`)
+}
+
+func TestRDFIgnoreUid(t *testing.T) {
+	query := `
+	{
+		me(func: anyofterms(name, "Michonne Rick Daryl")) {
+			uid
+			name
+		}
+	}`
+	rdf, err := processQueryRDF(context.Background(), t, query)
+	require.NoError(t, err)
+	require.Equal(t, rdf, `<0x1> <name> "Michonne" .
+<0x17> <name> "Rick Grimes" .
+<0x19> <name> "Daryl Dixon" .
+`)
+}
+
 func TestRDFCheckPwd(t *testing.T) {
 	query := `
     {