Add ability to expand only on certain types.

gql/parser.go

@@ -2186,6 +2186,38 @@ func parseVarList(it *lex.ItemIterator, gq *GraphQuery) (int, error) {
 	return count, nil
 }
 
+func parseTypeList(it *lex.ItemIterator, gq *GraphQuery) error {
+	typeList := it.Item().Val
+	expectArg := false
+loop:
+	for it.Next() {
+		item := it.Item()
+		switch item.Typ {
+		case itemRightRound:
+			it.Prev()
+			break loop
+		case itemComma:
+			if expectArg {
+				return item.Errorf("Expected a variable but got comma")
+			}
+			expectArg = true
+		case itemName:
+			if !expectArg {
+				return item.Errorf("Expected a variable but got comma")
+			}
+			typeList = fmt.Sprintf("%s,%s", typeList, item.Val)
+			expectArg = false
+		default:
+			return item.Errorf("Unexpected token %s when reading a type list", item.Val)
+		}
+	}
+	if expectArg {
+		return it.Item().Errorf("Unnecessary comma in val()")
+	}
+	gq.Expand = typeList
+	return nil
+}
+
 func parseDirective(it *lex.ItemIterator, curp *GraphQuery) error {
 	valid := true
 	it.Prev()
@@ -2807,7 +2839,9 @@ func godeep(it *lex.ItemIterator, gq *GraphQuery) error {
 				case "_reverse_":
 					child.Expand = "_reverse_"
 				default:
-					return item.Errorf("Invalid argument %v in expand()", item.Val)
+					if err := parseTypeList(it, child); err != nil {
+						return err
+					}
 				}
 				it.Next() // Consume ')'
 				gq.Children = append(gq.Children, child)

gql/parser_test.go

@@ -188,6 +188,34 @@ func TestParseQueryExpandReverse(t *testing.T) {
 	require.NoError(t, err)
 }
 
+func TestParseQueryExpandType(t *testing.T) {
+	query := `
+	{
+		var(func: uid( 0x0a)) {
+			friends {
+				expand(Person)
+			}
+		}
+	}
+`
+	_, err := Parse(Request{Str: query})
+	require.NoError(t, err)
+}
+
+func TestParseQueryExpandMultipleTypes(t *testing.T) {
+	query := `
+	{
+		var(func: uid( 0x0a)) {
+			friends {
+				expand(Person, Relative)
+			}
+		}
+	}
+`
+	_, err := Parse(Request{Str: query})
+	require.NoError(t, err)
+}
+
 func TestParseQueryAliasListPred(t *testing.T) {
 	query := `
 	{
@@ -4804,3 +4832,23 @@ func TestTypeFilterInPredicate(t *testing.T) {
 	require.Equal(t, 1, len(gq.Query[0].Children[0].Children))
 	require.Equal(t, "name", gq.Query[0].Children[0].Children[0].Attr)
 }
+
+func TestParseExpandType(t *testing.T) {
+	query := `
+	{
+		var(func: has(name)) {
+			expand(Person,Animal) {
+				uid
+			}
+		}
+	}
+`
+	gq, err := Parse(Request{Str: query})
+	require.NoError(t, err)
+	require.Equal(t, 1, len(gq.Query))
+	require.Equal(t, 1, len(gq.Query[0].Children))
+	require.Equal(t, "expand", gq.Query[0].Children[0].Attr)
+	require.Equal(t, "Person,Animal", gq.Query[0].Children[0].Expand)
+	require.Equal(t, 1, len(gq.Query[0].Children[0].Children))
+	require.Equal(t, "uid", gq.Query[0].Children[0].Children[0].Attr)
+}

query/common_test.go

@@ -207,6 +207,10 @@ type CarModel {
 	previous_model
 }
 
+type Object {
+	name: string
+}
+
 type SchoolInfo {
 	name
 	abbr
@@ -545,11 +549,13 @@ func populateCluster() {
 		<201> <dgraph.type> "CarModel" .
 		<201> <previous_model> <200> .
 
+		<202> <name> "Car" .
 		<202> <make> "Toyota" .
 		<202> <year> "2009" .
 		<202> <model> "Prius" .
 		<202> <model> "プリウス"@jp .
 		<202> <dgraph.type> "CarModel" .
+		<202> <dgraph.type> "Object" .
 
 		# data for regexp testing
 		_:luke <firstName> "Luke" .

query/query.go

@@ -1857,9 +1857,14 @@ func expandSubgraph(ctx context.Context, sg *SubGraph) ([]*SubGraph, error) {
 			}
 			preds = append(preds, rpreds...)
 		default:
-			span.Annotate(nil, "expand default")
-			// We already have the predicates populated from the var.
-			preds = getPredsFromVals(child.ExpandPreds)
+			if len(child.ExpandPreds) > 0 {
+				span.Annotate(nil, "expand default")
+				// We already have the predicates populated from the var.
+				preds = getPredsFromVals(child.ExpandPreds)
+			} else {
+				types := strings.Split(child.Params.Expand, ",")
+				preds = getPredicatesFromTypes(types)
+			}
 		}
 		preds = uniquePreds(preds)
 
@@ -1869,7 +1874,10 @@ func expandSubgraph(ctx context.Context, sg *SubGraph) ([]*SubGraph, error) {
 				Attr:   pred,
 			}
 			temp.Params = child.Params
-			temp.Params.ExpandAll = child.Params.Expand == "_all_"
+			// TODO(martinmr): simplify this condition once _reverse_ and _forward_
+			// are removed
+			temp.Params.ExpandAll = child.Params.Expand != "_reverse_" &&
+				child.Params.Expand != "_forward_"
 			temp.Params.ParentVars = make(map[string]varValue)
 			for k, v := range child.Params.ParentVars {
 				temp.Params.ParentVars[k] = v
@@ -2637,6 +2645,7 @@ func (req *Request) ProcessQuery(ctx context.Context) (err error) {
 				continue
 			}
 			sg := req.Subgraphs[idx]
+
 			// Check the list for the requires variables.
 			if !canExecute(idx) {
 				continue

query/query0_test.go

@@ -152,9 +152,9 @@ func TestQueryCountEmptyNames(t *testing.T) {
 		{in: `{q(func: has(name)) @filter(eq(name, "")) {count(uid)}}`,
 			out: `{"data":{"q": [{"count":2}]}}`},
 		{in: `{q(func: has(name)) @filter(gt(name, "")) {count(uid)}}`,
-			out: `{"data":{"q": [{"count":46}]}}`},
+			out: `{"data":{"q": [{"count":47}]}}`},
 		{in: `{q(func: has(name)) @filter(ge(name, "")) {count(uid)}}`,
-			out: `{"data":{"q": [{"count":48}]}}`},
+			out: `{"data":{"q": [{"count":49}]}}`},
 		{in: `{q(func: has(name)) @filter(lt(name, "")) {count(uid)}}`,
 			out: `{"data":{"q": [{"count":0}]}}`},
 		{in: `{q(func: has(name)) @filter(le(name, "")) {count(uid)}}`,
@@ -165,7 +165,7 @@ func TestQueryCountEmptyNames(t *testing.T) {
 			out: `{"data":{"q": [{"count":2}]}}`},
 		// NOTE: match with empty string filters values greater than the max distance.
 		{in: `{q(func: has(name)) @filter(match(name, "", 8)) {count(uid)}}`,
-			out: `{"data":{"q": [{"count":28}]}}`},
+			out: `{"data":{"q": [{"count":29}]}}`},
 		{in: `{q(func: has(name)) @filter(uid_in(name, "")) {count(uid)}}`,
 			failure: `Value "" in uid_in is not a number`},
 	}

query/query4_test.go

@@ -335,7 +335,32 @@ func TestTypeExpandLang(t *testing.T) {
 	}`
 	js := processQueryNoErr(t, query)
 	require.JSONEq(t, `{"data": {"q":[
-		{"make":"Toyota","model":"Prius", "model@jp":"プリウス", "year":2009}]}}`, js)
+		{"name": "Car", "make":"Toyota","model":"Prius", "model@jp":"プリウス", "year":2009}]}}`, js)
+}
+
+func TestTypeExpandExplicitType(t *testing.T) {
+	query := `{
+		q(func: eq(make, "Toyota")) {
+			expand(Object) {
+				uid
+			}
+		}
+	}`
+	js := processQueryNoErr(t, query)
+	require.JSONEq(t, `{"data": {"q":[{"name":"Car"}]}}`, js)
+}
+
+func TestTypeExpandMultipleExplicitTypes(t *testing.T) {
+	query := `{
+		q(func: eq(make, "Toyota")) {
+			expand(CarModel, Object) {
+				uid
+			}
+		}
+	}`
+	js := processQueryNoErr(t, query)
+	require.JSONEq(t, `{"data": {"q":[
+		{"name": "Car", "make":"Toyota","model":"Prius", "model@jp":"プリウス", "year":2009}]}}`, js)
 }
 
 // Test Related to worker based pagination.

query/query_facets_test.go

@@ -915,6 +915,6 @@ func TestTypeExpandFacets(t *testing.T) {
 	}`
 	js := processQueryNoErr(t, query)
 	require.JSONEq(t, `{"data": {"q":[
-		{"make":"Toyota","model":"Prius", "model@jp":"プリウス", "model|type":"Electric",
-			"year":2009}]}}`, js)
+		{"name": "Car", "make":"Toyota","model":"Prius", "model@jp":"プリウス",
+			"model|type":"Electric", "year":2009}]}}`, js)
 }