Flutter build web 构建没有健全的 null 安全并且在错误时运行

Question

运行 flutter build web 给出以下错误：

flutter build web
Changing current working directory to: /home/forest/projects/icell/i_cell_parking_manager

Building without sound null safety
For more information see https://dart.dev/null-safety/unsound-null-safety

Target dart2js failed: Exception: ../../../snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/cloud_firestore_web-1.0.1/lib/src/interop/utils/utils.dart:15:41:
Error: The argument type 'Object? Function(Object)' can't be assigned to the parameter type 'Object? Function(Object?)?' because 'Object?' is nullable and 'Object' isn't.
 - 'Object' is from 'dart:core'.
  return core_interop.dartify(jsObject, (Object object) {
                                        ^
../../../snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/cloud_firestore_web-1.0.1/lib/src/interop/utils/utils.dart:39:41:
Error: The argument type 'dynamic Function(Object)' can't be assigned to the parameter type 'Object? Function(Object?)?' because 'Object?' is nullable and 'Object' isn't.
 - 'Object' is from 'dart:core'.
  return core_interop.jsify(dartObject, (Object object) {
                                        ^
Error: Compilation failed.


Compiling lib/main.dart for the Web...                              8.3s
Exception: Failed to compile application for the Web.

android 的构建工作没有任何错误 (flutter build apk)。

flutter doctor

Flutter 2.0.3 • channel stable • https://github.com/flutter/flutter.git
Framework • revision 4d7946a68d (10 days ago) • 2021-03-18 17:24:33 -0700
Engine • revision 3459eb2436
Tools • Dart 2.12.2

Running flutter doctor...
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 2.0.3, on Linux, locale en_US.UTF-8)
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
[✓] Chrome - develop for the web
[!] Android Studio (not installed)
[✓] IntelliJ IDEA Ultimate Edition (version 2020.2)
[✓] Connected device (2 available)
! Doctor found issues in 1 category.

（未安装Androd studio很奇怪，因为我是运行它的项目，我使用AVD的虚拟设备没问题...）

我的 index.html 导入了最新的库：

...

  <script src="https://www.gstatic.com/firebasejs/7.8.0/firebase-auth.js"></script>
  <script src="https://www.gstatic.com/firebasejs/7.20.0/firebase-app.js"></script>

相关pubspec.yaml部分：

dependencies:
  flutter:
    sdk: flutter
  flutter_localizations:
    sdk: flutter
  flutter_spinkit: "^4.1.2"
  cloud_firestore: ^1.0.1
  cloud_functions: "^1.0.2"
  provider: ^5.0.0
  google_sign_in: ^5.0.0
  firebase_core: ^1.0.1
  firebase_messaging: ^9.0.0
  firebase_auth: ^1.0.1

Answer 1

解决方案是运行

flutter pub upgrade 和 flutter pub outdated 然后 flutter pub get 并解决了问题。

我怀疑某些东西被缓存了，并且在开始时并没有在 web 构建中使用所有新的依赖项，但不知道为什么它突然起作用了：\

Answer 2

要制作没有空安全的发布版本，请使用：

flutter build web --no-sound-null-safety

生成的文件将放在build/web.

下

^{NOTE: The --no-sound-null-safety must be passed as a flag to the web subcommand, and not to build or flutter.}

^{NOTE2: The build sets <base href="/"> therefore unless you serve your app from the webserver root you'll need to adjust the value to the correct path. There is a github issue to make the base href configurable via a command line parameter. The current docs recommend to set the base href by hand.}

Answer 3

如果您使用 mac 或 linux，请在您的终端中输入，以导出此 EXTRA_FRONT_END_OPTIONS 变量，如下所示

导出EXTRA_FRONT_END_OPTIONS=--no-sound-null-safety

Flutter build web 构建没有健全的 null 安全并且在错误时运行

Flutter build web builds without sound null safety and runs on error

flutter

flutter-web