ensureDefaults function

Map<String, Object?> ensureDefaults(Map<String, Object?> message, List<Map<String, Object?>> descriptor)

Returns a copy of message with missing fields filled in with proto3 default values according to descriptor.

Fields already present in the map are left unchanged. Fields absent from the map are inserted with their type-appropriate default: 0, 0.0, false, "", empty list, or null.

Implementation

Map<String, Object?> ensureDefaults(
  Map<String, Object?> message,
  List<Map<String, Object?>> descriptor,
) {
  final result = Map<String, Object?>.from(message);
  for (final field in descriptor) {
    final name = field['name'] as String;
    if (result.containsKey(name)) continue;

    final type = field['type'] as String;
    final label = field['label'] as String?;
    final isMap = field['mapEntry'] == true;

    if (isMap) {
      result[name] = <String, Object?>{};
    } else if (label == 'LABEL_REPEATED') {
      result[name] = <Object?>[];
    } else {
      result[name] = _defaultForType(type);
    }
  }
  return result;
}