Merge pull request #129 from goccy/feature/resolve-alias-before-unmar…

…shal-yaml

Resolve alias node before calling UnmarshalYAML([]byte)

decode.go

@@ -214,6 +214,26 @@ func (d *Decoder) nodeToValue(node ast.Node) interface{} {
 	return nil
 }
 
+func (d *Decoder) resolveAlias(node ast.Node) ast.Node {
+	switch n := node.(type) {
+	case *ast.MappingNode:
+		for idx, value := range n.Values {
+			n.Values[idx] = d.resolveAlias(value).(*ast.MappingValueNode)
+		}
+	case *ast.MappingValueNode:
+		n.Key = d.resolveAlias(n.Key)
+		n.Value = d.resolveAlias(n.Value)
+	case *ast.SequenceNode:
+		for idx, value := range n.Values {
+			n.Values[idx] = d.resolveAlias(value)
+		}
+	case *ast.AliasNode:
+		aliasName := n.Value.GetToken().Value
+		return d.anchorNodeMap[aliasName]
+	}
+	return node
+}
+
 func (d *Decoder) getMapNode(node ast.Node) (ast.MapNode, error) {
 	if _, ok := node.(*ast.NullNode); ok {
 		return nil, nil
@@ -399,6 +419,7 @@ func (d *Decoder) decodeValue(dst reflect.Value, src ast.Node) error {
 	}
 	valueType := dst.Type()
 	if unmarshaler, ok := dst.Addr().Interface().(BytesUnmarshaler); ok {
+		src = d.resolveAlias(src)
 		var b string
 		if scalar, isScalar := src.(ast.ScalarNode); isScalar {
 			b = fmt.Sprint(scalar.GetValue())

decode_test.go

@@ -1875,3 +1875,52 @@ k: l
 		t.Fatal("failed to stream decoding")
 	}
 }
+
+type unmarshalYAMLWithAliasString string
+
+func (v *unmarshalYAMLWithAliasString) UnmarshalYAML(b []byte) error {
+	var s string
+	if err := yaml.Unmarshal(b, &s); err != nil {
+		return err
+	}
+	*v = unmarshalYAMLWithAliasString(s)
+	return nil
+}
+
+type unmarshalYAMLWithAliasMap map[string]interface{}
+
+func (v *unmarshalYAMLWithAliasMap) UnmarshalYAML(b []byte) error {
+	var m map[string]interface{}
+	if err := yaml.Unmarshal(b, &m); err != nil {
+		return err
+	}
+	*v = unmarshalYAMLWithAliasMap(m)
+	return nil
+}
+
+func TestDecoder_UnmarshalYAMLWithAlias(t *testing.T) {
+	yml := `
+anchors:
+ x: &x hello
+ map: &y
+  a: b
+  c: d
+a: *x
+b:
+ <<: *y
+ e: f
+`
+	var v struct {
+		A unmarshalYAMLWithAliasString
+		B unmarshalYAMLWithAliasMap
+	}
+	if err := yaml.Unmarshal([]byte(yml), &v); err != nil {
+		t.Fatalf("%+v", err)
+	}
+	if v.A != "hello" {
+		t.Fatal("failed to unmarshal with alias")
+	}
+	if len(v.B) != 3 {
+		t.Fatal("failed to unmarshal with alias")
+	}
+}