英文:
Can a closure be sent to a SendPort
问题
我正在实现双独立体应用程序。在此范围内，我正在探索通过 SendPort 发送闭包的可能性。文档 表示，在隔离体共享相同代码的情况下，可以发送任何东西，但有一些例外情况。但当我尝试调用此代码时
port.send(() {});
我收到一个错误:
> E/flutter (26634): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] 未处理的异常: 参数无效：隔离消息中的非法参数: （对象是闭包 - 函数'＜匿名闭包＞'：.）
这是预期行为，只是不能通过 SendPort 发送函数吗？
我的环境是:
Flutter 3.3.9 • 稳定通道 • https://github.com/flutter/flutter.git
框架 • 修订版 b8f7f1f986（6 个月前） • 2022-11-23 06:43:51 +0900
引擎 • 修订版 8f2221fbef
工具 • Dart 2.18.5 • DevTools 2.15.0
英文:
I'm working on implementation two-isolates app. In this scope I'm exploring a possibility to send a closure via SendPort. The documentation says that in case isolates share same code anything can be sent with some exceptions. But when I try to call this
port.send(() {});
I get an error:
> E/flutter (26634): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Invalid argument(s): Illegal argument in isolate message : (object is a closure - Function '<anonymous closure>':.)
Is that expected behavior and one just can't send functions via SendPort?
My environment is:
Flutter 3.3.9 • channel stable • https://github.com/flutter/flutter.git
Framework • revision b8f7f1f986 (6 months ago) • 2022-11-23 06:43:51 +0900
Engine • revision 8f2221fbef
Tools • Dart 2.18.5 • DevTools 2.15.0
答案1
得分: 1
自Dart 2.15版本开始，默认启用隔离组，使用Isolate.spawn()启动的隔离现在共享相同的代码，并允许在隔离消息中包含闭包。
如果闭包的封闭上下文包含不可发送的消息，则可能会失败。
由于此问题，通常不建议将闭包发送给隔离。请参阅dart-lang/sdk#36983，其中与另一个问题相关的讨论。
有关更多信息，请查看Dart 2.15.0变更日志中的Dart VM部分。
英文:
Since Dart 2.15, which enables isolate groups by default, isolates started with Isolate.spawn() share the same code and allow including closures in inter-isolate messages.
This may fail if the closure's enclosing context contains messages that are not sendable.
Sending closures to isolates is generally discouraged due to this issue. See dart-lang/sdk#36983, where this is discussed in relation to another issue.
See the Dart VM section of the Dart 2.15.0 changelog for more information.
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