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我尝试使用空安全，但它给了我这个错误：

这需要启用“不可为空”语言功能。尝试更新 pubspec.yaml 以将最小 SDK 约束设置为 2.10.0 或更高版本，并运行“pub get”。

我将 Dart SDK 约束从 更改2.7.0为2.10.0，但它仍然显示此错误。

另外，我升级了我的 Dart 和 Flutter SDK：

dart-sdk v2.10.2 是基于您的来源的最新版本。

颤动（通道稳定，1.22.3，...

我正在尝试迁移 dart null safety，但运行时出现以下错误dart migrate

Bad state: Error: package has unmigrated dependencies.\n\nBefore migrating your package, we recommend ensuring that every library it\nimports (either directly or indirectly) has been migrated to null safety, so\nthat you will be able to run your unit tests in sound null checking mode.  You\nare currently importing the following non-null-safe libraries:\n\n  file:///C:/flutter/packages/flutter_tools/test/integration.shard/test_data/basic_project.dart\n  file:///C:/flutter/packages/flutter_tools/test/integration.shard/test_data/deferred_components_config.dart\n  file:///C:/flutter/packages/flutter_tools/test/integration.shard/test_data/project.dart\n  file:///C:/flutter/packages/flutter_tools/test/integration.shard/test_driver.dart\n  file:///C:/flutter/packages/flutter_tools/test/src/test_flutter_command_runner.dart\n  file:///C:/flutter/packages/flutter_tools/test/src/testbed.dart\n package:dwds/data/build_result.dart\n  package:dwds/data/connect_request.dart\n  package:dwds/data/debug_event.dart\n  package:dwds/data/devtools_request.dart\n  package:dwds/data/error_response.dart\n  package:dwds/data/extension_request.dart\n  package:dwds/data/isolate_events.dart\n  package:dwds/data/register_event.dart\n  package:dwds/src/debugging/dart_scope.dart\n  package:dwds/src/debugging/debugger.dart\n  package:dwds/src/debugging/execution_context.dart\n  package:dwds/src/debugging/frame_computer.dart\n  package:dwds/src/debugging/inspector.dart\n  package:dwds/src/debugging/instance.dart\n  package:dwds/src/debugging/libraries.dart\n  package:dwds/src/debugging/location.dart\n  package:dwds/src/debugging/metadata/class.dart\n  package:dwds/src/debugging/metadata/function.dart\n …