Build fails due to the usage of TypeConverters with optional property, is this a bug?

[pratamatama]

I'm trying to make an extendable base entity that contains an id, updatedAt, and createdAt field.

The updatedAt should always be a DateTime.now() that refers to the current time, meanwhile the createdAt should take the original DateTime associated within records if not provided.

datetime_converter.dart

class DateTimeConverter extends TypeConverter<DateTime, int> {
  @override
  DateTime decode(int databaseValue) {
    return DateTime.fromMillisecondsSinceEpoch(databaseValue);
  }

  @override
  int encode(DateTime value) {
    return value.millisecondsSinceEpoch;
  }
}

base.dart

class BaseEntity {
  @PrimaryKey(autoGenerate: true)
  final int? id;

  @ColumnInfo(name: 'created_at')
  final DateTime createdAt;

  @ColumnInfo(name: 'updated_at')
  final DateTime updatedAt;

  BaseEntity({
    this.id,
    DateTime? updatedAt,
    DateTime? createdAt,
  })  : createdAt = createdAt ?? DateTime.now(),
        updatedAt = DateTime.now();
}

category.dart

@Entity(tableName: 'categories')
class Category extends BaseEntity {
  final String name;

  @ColumnInfo(name: 'label_color')
  final int? labelColor;

  Category(
    this.name,
    this.labelColor, {
    int? id,
    DateTime? createdAt,
    DateTime? updatedAt,
  }) : super(id: id, createdAt: createdAt, updatedAt: updatedAt);

  @override
  bool operator ==(Object other) =>
      identical(this, other) ||
      other is Category &&
          runtimeType == other.runtimeType &&
          id == other.id &&
          name == other.name &&
          labelColor == other.labelColor &&
          createdAt == other.createdAt &&
          updatedAt == other.updatedAt;

  @override
  int get hashCode =>
      id.hashCode ^
      name.hashCode ^
      labelColor.hashCode ^
      createdAt.hashCode ^
      updatedAt.hashCode;

  @override
  String toString() {
    return 'Category { '
        'id: $id, '
        'name: $name, '
        'labelColor: $labelColor, '
        'createdAt: $createdAt, '
        'updatedAt: $updatedAt '
        '}';
  }
}

It works fine if I change the type to String and use DateTime.now().toIso8601String() but I can't think a way to sort by date this way so I decided to make a TypeConverter. I copied the snippets from the docs and uses it on my app.

Because I know those values are unmodifiable by the user, I decided to make it optional to avoid writing DateTime.now() repeatedly and set it from the constructor instead.

However, when I try to rebuild my app, it fails with this error

PS D:\Yura\Projs\myapp> flutter packages pub run build_runner build --delete-conflicting-outputs
[INFO] Generating build script...
[INFO] Generating build script completed, took 1.3s

[INFO] Initializing inputs
[INFO] Reading cached asset graph...
[INFO] Reading cached asset graph completed, took 186ms

[INFO] Checking for updates since last build...
[INFO] Checking for updates since last build completed, took 3.3s

[INFO] Running build...
[INFO] 1.0s elapsed, 0/1 actions completed.
[INFO] 2.0s elapsed, 0/1 actions completed.
[INFO] 3.1s elapsed, 0/1 actions completed.
[INFO] 4.3s elapsed, 0/1 actions completed.
[INFO] 5.4s elapsed, 0/1 actions completed.
[INFO] 6.5s elapsed, 0/1 actions completed.
[INFO] 24.3s elapsed, 0/1 actions completed.
[WARNING] No actions completed for 24.3s, waiting on:
  - floor_generator:floor_generator on lib/app/data/database.dart

[SEVERE] floor_generator:floor_generator on lib/app/data/database.dart:

Column type is not supported for DateTime?
[INFO] Running build completed, took 25.4s

[INFO] Caching finalized dependency graph...
[INFO] Caching finalized dependency graph completed, took 224ms

[SEVERE] Failed after 25.7s
pub finished with exit code 1

Is this a bug? Or I implemented it in a wrong way? If that's the case, what's the possible solution to achieve this requirement?

[pratamatama]

Ah, there is already an open issue about this (#508). Will close the discussion now.