Breaking change: Remove expand(_forward_) and expand(_reverse_).

gql/parser.go

@@ -2802,10 +2802,6 @@ func godeep(it *lex.ItemIterator, gq *GraphQuery) error {
 					child.Expand = child.NeedsVar[len(child.NeedsVar)-1].Name
 				case "_all_":
 					child.Expand = "_all_"
-				case "_forward_":
-					child.Expand = "_forward_"
-				case "_reverse_":
-					child.Expand = "_reverse_"
 				default:
 					return item.Errorf("Invalid argument %v in expand()", item.Val)
 				}

gql/parser_test.go

@@ -160,34 +160,6 @@ func TestParseQueryListPred1(t *testing.T) {
 	require.NoError(t, err)
 }
 
-func TestParseQueryExpandForward(t *testing.T) {
-	query := `
-	{
-		var(func: uid( 0x0a)) {
-			friends {
-				expand(_forward_)
-			}
-		}
-	}
-`
-	_, err := Parse(Request{Str: query})
-	require.NoError(t, err)
-}
-
-func TestParseQueryExpandReverse(t *testing.T) {
-	query := `
-	{
-		var(func: uid( 0x0a)) {
-			friends {
-				expand(_reverse_)
-			}
-		}
-	}
-`
-	_, err := Parse(Request{Str: query})
-	require.NoError(t, err)
-}
-
 func TestParseQueryAliasListPred(t *testing.T) {
 	query := `
 	{

query/query.go

@@ -1824,7 +1824,7 @@ func expandSubgraph(ctx context.Context, sg *SubGraph) ([]*SubGraph, error) {
 		}
 
 		switch child.Params.Expand {
-		// It could be expand(_all_), expand(_forward_), expand(_reverse_) or expand(val(x)).
+		// It could be expand(_all_) or expand(val(x)).
 		case "_all_":
 			span.Annotate(nil, "expand(_all_)")
 			if len(types) == 0 {
@@ -1837,25 +1837,6 @@ func expandSubgraph(ctx context.Context, sg *SubGraph) ([]*SubGraph, error) {
 				return out, err
 			}
 			preds = append(preds, rpreds...)
-		case "_forward_":
-			span.Annotate(nil, "expand(_forward_)")
-			if len(types) == 0 {
-				break
-			}
-
-			preds = getPredicatesFromTypes(types)
-		case "_reverse_":
-			span.Annotate(nil, "expand(_reverse_)")
-			if len(types) == 0 {
-				break
-			}
-
-			typePreds := getPredicatesFromTypes(types)
-			rpreds, err := getReversePredicates(ctx, typePreds)
-			if err != nil {
-				return out, err
-			}
-			preds = append(preds, rpreds...)
 		default:
 			span.Annotate(nil, "expand default")
 			// We already have the predicates populated from the var.

query/query4_test.go

@@ -296,35 +296,6 @@ func TestTypeExpandAll(t *testing.T) {
 	]}}`, js)
 }
 
-func TestTypeExpandForward(t *testing.T) {
-	query := `{
-		q(func: eq(make, "Ford")) {
-			expand(_forward_) {
-				uid
-			}
-		}
-	}`
-	js := processQueryNoErr(t, query)
-	require.JSONEq(t, `{"data": {"q":[
-		{"make":"Ford","model":"Focus","year":2008},
-		{"make":"Ford","model":"Focus","year":2009, "previous_model": {"uid":"0xc8"}}
-	]}}`, js)
-}
-
-func TestTypeExpandReverse(t *testing.T) {
-	query := `{
-		q(func: eq(make, "Ford")) {
-			expand(_reverse_) {
-				uid
-			}
-		}
-	}`
-	js := processQueryNoErr(t, query)
-	require.JSONEq(t, `{"data": {"q":[
-		{"~previous_model": [{"uid":"0xc9"}]}
-	]}}`, js)
-}
-
 func TestTypeExpandLang(t *testing.T) {
 	query := `{
 		q(func: eq(make, "Toyota")) {

wiki/content/query-language/index.md

@@ -1800,10 +1800,6 @@ There are four ways to use the `expand` function.
 * If `_all_` is passed as an argument to `expand()`, all the predicates for each
   node at that level are retrieved. More levels can be specified in a nested
   fashion under `expand()`.
-* If `_forward_` is passed as an argument to `expand()`, all predicates for each
-  node at that level (minus any reverse predicates) are retrieved.
-* If `_reverse_` is passed as an argument to `expand()`, only the reverse
-  predicates at each node in that level are retrieved.
 
 The last three keywords require that the nodes have types. Dgraph will look 
 for all the types that have been assigned to a node,
@@ -2509,8 +2505,7 @@ err := c.Alter(context.Background(), &api.Operation{
 ### Expand queries and types
 
 Queries using [expand]({{< relref "#expand-predicates" >}}) (i.e.:
-`expand(_all_)`, `expand(_reverse_)`, or `expand(_forward_)`) require that the
-nodes to expand have types.
+`expand(_all_)`) require that the nodes to be expanded have types.
 
 ## Facets : Edge attributes