flutter - 如何修复 “Failed to snapshot build script”

Question

我为Web和Dart SDK安装了Flutter。添加到路径bin文件夹。跑oji​​t_code和flutter pub global activate webdev，但是输入flutter pub upgrade后，我总是报错”:

[SEVERE] Failed to snapshot build script .dart_tool/build/entrypoint/build.dart.
[SEVERE] This is likely caused by a misconfigured builder definition.
[SEVERE] /C:/flutter/.pub-cache/hosted/pub.dartlang.org/protobuf-0.13.16/lib/src/protobuf/builder_info.dart:43:34: Error: Method not found: 'MapFieldInfo.map'.    _addField(MapFieldInfo<K, V>.map(name, tagNumber, index, PbFieldType.M,                                 ^^^/C:/flutter/.pub-cache/hosted/pub.dartlang.org/protobuf-0.13.16/lib/src/protobuf/field_info.dart:45:9: Error: '_mapEntryBuilderInfo' isn't an instance field of this class.        _mapEntryBuilderInfo = null {        ^^^^^^^^^^^^^^^^^^^^/C:/flutter/.pub-cache/hosted/pub.dartlang.org/protobuf-0.13.16/lib/src/protobuf/field_info.dart:61:9: Error: '_mapEntryBuilderInfo' isn't an instance field of this class.        _mapEntryBuilderInfo = null;        ^^^^^^^^^^^^^^^^^^^^/C:/flutter/.pub-cache/hosted/pub.dartlang.org/protobuf-0.13.16/lib/src/protobuf/field_info.dart:68:9: Error: '_mapEntryBuilderInfo' isn't an instance field of this class.        _mapEntryBuilderInfo = null {        ^^^^^^^^^^^^^^^^^^^^/C:/flutter/.pub-cache/hosted/pub.dartlang.org/protobuf-0.13.16/lib/src/protobuf/field_info.dart:82:12: Error: '_mapEntryBuilderInfo' isn't an instance field of this class.      this._mapEntryBuilderInfo])           ^^^^^^^^^^^^^^^^^^^^/C:/flutter/.pub-cache/hosted/pub.dartlang.org/protobuf-0.13.16/lib/src/protobuf/field_info.dart:199:9: Error: Superclass has no constructor named 'FieldInfo._'.      : super._(        ^^^^^/C:/flutter/.pub-cache/hosted/pub.dartlang.org/protobuf-0.13.16/lib/src/protobuf/field_info.dart:195:21: Error: Final field '_mapEntryBuilderInfo' is not initialized.Try to#7      _CommandRunner.runCommand (package:webdev/src/webdev_command_runner.dart:38:24)
<asynchronous suspension>
#8      CommandRunner.run.<anonymous closure> (package:args/command_runner.dart:112:25)
#9      new Future.sync (dart:async/future.dart:224:31)
#10     CommandRunner.run (package:args/command_runner.dart:112:14)
#11     run (package:webdev/src/webdev_command_runner.dart:19:56)
#12     main (file:///C:/flutter/.pub-cache/hosted/pub.dartlang.org/webdev-2.5.1/bin/webdev.dart:17:22)
<asynchronous suspension>
#13     _startIsolate.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:303:32)
#14     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:172:12)

flutter 医生:

Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, v1.9.1+hotfix.2, on Microsoft Windows [Version 10.0.18362.356], locale ru-RU)
[X] Android toolchain - develop for Android devices
    X Unable to locate Android SDK.
      Install Android Studio from: https://developer.android.com/studio/index.html
      On first launch it will assist you in installing the Android SDK components.
      (or visit https://flutter.dev/setup/#android-setup for detailed instructions).
      If the Android SDK has been installed to a custom location, set ANDROID_HOME to that location.
      You may also want to add it to your PATH environment variable.

[!] Android Studio (not installed)
[√] VS Code (version 1.38.1)
[!] Connected device
    ! No devices available

! Doctor found issues in 3 categories.

pubspec.yaml:

name: addd
description: An app built using Flutter for web

environment:
  # You must be using Flutter >=1.5.0 or Dart >=2.3.0
  sdk: '>=2.3.0 <3.0.0'

dependencies:
  flutter_web: any
  flutter_web_ui: any

dev_dependencies:
  build_runner: ^1.5.0
  build_web_compilers: ^2.1.0
  pedantic: ^1.7.0

dependency_overrides:
  flutter_web:
    git:
      url: https://github.com/flutter/flutter_web
      path: packages/flutter_web
  flutter_web_ui:
    git:
      url: https://github.com/flutter/flutter_web
      path: packages/flutter_web_ui

如何解决？

UPD。添加了更多详细信息(Flutter Doctor和pubspec.yaml)

Answer 1

嗨，我今天也遇到了同样的问题。通过运气和与正常工作的版本进行比较，我发现它被protobuf版本> 0.13.15破坏了。

短期修复:

在依赖性下的pubspec.yaml中，将protobuf的版本降级为0.13.15:

dependencies:
  protobuf: <=0.13.15

正常运行 pub get然后运行 webdev serve。