领域驱动设计：冻结的 dart 包给出“失败的断言布尔表达式不能为空”

如何解决领域驱动设计：冻结的 dart 包给出“失败的断言布尔表达式不能为空”

我正在尝试使用本教程构建带有身份验证的电子邮件模型 https://www.youtube.com/watch?v=fdUwW0GgcS8&list=PLB6lc7nQ1n4iS5p-IezFFgqP6YvAJy84U&index=2

import 'package:Flutter/cupertino.dart';
import 'package:dartz/dartz.dart';
import 'package:freezed_annotation/freezed_annotation.dart';
import 'package:Flutter/foundation.dart';

part 'email_address.freezed.dart';

//https://www.youtube.com/watch?v=fdUwW0GgcS8&list=PLB6lc7nQ1n4iS5p-IezFFgqP6YvAJy84U&index=2

// Make Illegal states unrepresentable

@immutable
class EmailAddress {
  final Either<ValueFailure<String>,String> value;

  factory EmailAddress(String input) {
    //assert input is not null
    assert(input != null);

    //use private constructor
    return EmailAddress._(
      validateEmailAddress(input),);
  }

  // private constructor which will be used in factory constructor if email is valid.
  const EmailAddress._(this.value);

  @override
  String toString() {
    return 'EmailAddress($value)';
  }

  @override
  bool operator ==(Object o) {
    if (identical(this,o)) return true;

    return o is EmailAddress && o.value == value;
  }

  @override
  int get hashCode => value.hashCode;
}

// Use a REGEX expression to valid the email address.
Either<ValueFailure<String>,String> validateEmailAddress(String input) {
  const emailRegex =
      r"""^[a-zA-Z0-9.a-zA-Z0-9.!#$%&'*+-/=?^_`{|}~]+@[a-zA-Z0-9]+\.[a-zA-Z]+""";
  if (RegExp(emailRegex).hasMatch(input)) {
    // right side of Either gives String of valid email
    return right(input);
  } else {
    // left side of either gives ValueFailure<String>
    return left(ValueFailure.invalidEmail(FailedValue: input));
  }
}

@freezed
abstract class ValueFailure<T> with _$ValueFailure<T> {
  const factory ValueFailure.invalidEmail({
    @required String FailedValue,}) = InvalidEmail<T>;
  const factory ValueFailure.shortPassword({
    @required String FailedValue,}) = ShortPassword<T>;
}

但是，我在使冻结的包正常工作时遇到了许多问题。

首先收到关于 SDK 和分析器之间版本冲突的错误：

Your current `analyzer` version may not fully support your current SDK version.

Please try upgrading to the latest `analyzer` by running `Flutter packages upgrade`.

Analyzer language version: 2.10.0
SDK language version: 2.12.0

我将以下内容添加到 pub spec.yaml 中，这似乎修复了它：

dependency_overrides:
  analyzer: ^0.41.1

但是，现在我在运行 Flutter pub run build_runner watch 时收到以下错误，

[INFO] 7.8s elapsed,3/4 actions completed.
[SEVERE] freezed:freezed on lib/domain/auth/email_address.dart:

Failed assertion: boolean expression must not be null
[INFO] Running build completed,took 8.1s.

我尝试添加

analyzer:
  enable-experiment:
    - non-nullable

基于一些谷歌搜索到 analysis_options.yaml 但仍然得到错误。

任何帮助将不胜感激！

解决方法

我已经尝试了您的代码，解决方案是在 freezed 中设置特定版本的 pubspec.yaml：

dependencies:
  freezed_annotation: ^0.12.0
dev_dependencies:
  freezed: ^0.12.2

无需覆盖 analyzer 软件包版本。

这适用于 Flutter 2.0.3 和 Dart 2.12.2。