Update github.com/xenolf/lego to 0.4.1

vendor/google.golang.org/api/gensupport/json.go

@@ -12,29 +12,43 @@ import (
 )
 
 // MarshalJSON returns a JSON encoding of schema containing only selected fields.
-// A field is selected if:
-//   * it has a non-empty value, or
-//     * its field name is present in forceSendFields, and
-//     * it is not a nil pointer or nil interface.
+// A field is selected if any of the following is true:
+//   * it has a non-empty value
+//   * its field name is present in forceSendFields and it is not a nil pointer or nil interface
+//   * its field name is present in nullFields.
 // The JSON key for each selected field is taken from the field's json: struct tag.
-func MarshalJSON(schema interface{}, forceSendFields []string) ([]byte, error) {
-	if len(forceSendFields) == 0 {
+func MarshalJSON(schema interface{}, forceSendFields, nullFields []string) ([]byte, error) {
+	if len(forceSendFields) == 0 && len(nullFields) == 0 {
 		return json.Marshal(schema)
 	}
 
-	mustInclude := make(map[string]struct{})
+	mustInclude := make(map[string]bool)
 	for _, f := range forceSendFields {
-		mustInclude[f] = struct{}{}
+		mustInclude[f] = true
+	}
+	useNull := make(map[string]bool)
+	useNullMaps := make(map[string]map[string]bool)
+	for _, nf := range nullFields {
+		parts := strings.SplitN(nf, ".", 2)
+		field := parts[0]
+		if len(parts) == 1 {
+			useNull[field] = true
+		} else {
+			if useNullMaps[field] == nil {
+				useNullMaps[field] = map[string]bool{}
+			}
+			useNullMaps[field][parts[1]] = true
+		}
 	}
 
-	dataMap, err := schemaToMap(schema, mustInclude)
+	dataMap, err := schemaToMap(schema, mustInclude, useNull, useNullMaps)
 	if err != nil {
 		return nil, err
 	}
 	return json.Marshal(dataMap)
 }
 
-func schemaToMap(schema interface{}, mustInclude map[string]struct{}) (map[string]interface{}, error) {
+func schemaToMap(schema interface{}, mustInclude, useNull map[string]bool, useNullMaps map[string]map[string]bool) (map[string]interface{}, error) {
 	m := make(map[string]interface{})
 	s := reflect.ValueOf(schema)
 	st := s.Type()
@@ -54,10 +68,36 @@ func schemaToMap(schema interface{}, mustInclude map[string]struct{}) (map[strin
 
 		v := s.Field(i)
 		f := st.Field(i)
+
+		if useNull[f.Name] {
+			if !isEmptyValue(v) {
+				return nil, fmt.Errorf("field %q in NullFields has non-empty value", f.Name)
+			}
+			m[tag.apiName] = nil
+			continue
+		}
+
 		if !includeField(v, f, mustInclude) {
 			continue
 		}
 
+		// If map fields are explicitly set to null, use a map[string]interface{}.
+		if f.Type.Kind() == reflect.Map && useNullMaps[f.Name] != nil {
+			ms, ok := v.Interface().(map[string]string)
+			if !ok {
+				return nil, fmt.Errorf("field %q has keys in NullFields but is not a map[string]string", f.Name)
+			}
+			mi := map[string]interface{}{}
+			for k, v := range ms {
+				mi[k] = v
+			}
+			for k := range useNullMaps[f.Name] {
+				mi[k] = nil
+			}
+			m[tag.apiName] = mi
+			continue
+		}
+
 		// nil maps are treated as empty maps.
 		if f.Type.Kind() == reflect.Map && v.IsNil() {
 			m[tag.apiName] = map[string]string{}
@@ -127,7 +167,7 @@ func parseJSONTag(val string) (jsonTag, error) {
 }
 
 // Reports whether the struct field "f" with value "v" should be included in JSON output.
-func includeField(v reflect.Value, f reflect.StructField, mustInclude map[string]struct{}) bool {
+func includeField(v reflect.Value, f reflect.StructField, mustInclude map[string]bool) bool {
 	// The regular JSON encoding of a nil pointer is "null", which means "delete this field".
 	// Therefore, we could enable field deletion by honoring pointer fields' presence in the mustInclude set.
 	// However, many fields are not pointers, so there would be no way to delete these fields.
@@ -144,8 +184,7 @@ func includeField(v reflect.Value, f reflect.StructField, mustInclude map[string
 		return false
 	}
 
-	_, ok := mustInclude[f.Name]
-	return ok || !isEmptyValue(v)
+	return mustInclude[f.Name] || !isEmptyValue(v)
 }
 
 // isEmptyValue reports whether v is the empty value for its type.  This