使用dart的异步与stack_trace的链 [英] Using dart's async with stack_trace's Chain

问题描述

我试图利用stack_trace提供的Chain对象，如下：

I'm trying to take advantage of the Chain object provided by stack_trace like so:

import 'dart:async';
import 'package:stack_trace/stack_trace.dart';

main() async {
  print('Hello world: ${console_test.calculate()}!');
  Chain.capture(() async {
    try {
      await testFunction();
    } catch(e,st) {
      print(Trace.format(new Chain.forTrace(st)));
    }
  });
}


Future testFunction() async {
  throw new Exception("TEST");
}

我得到的输出是：

Hello world: 42!
main.dart 4:1  main.<async>.<fn>.<async>

我理解输出的堆栈跟踪应包括testFunction，但由于某种原因不是。如果我用futures代替：

I understand that the outputted stack trace should include testFunction, but for some reason it isn't. If I do it with futures instead:

import 'dart:async';
import 'package:stack_trace/stack_trace.dart';

main() async {
  print('Hello world: ${console_test.calculate()}!');
  Chain.capture(()  {
      return testFunction();
  }, onError: (e, stackTrace) => print(Trace.format(new Chain.forTrace(stackTrace))));
}

Future testFunction() async {
  throw new Exception("TEST");
}

我得到更多的预期输出：

I get more expected output:

Hello world: 42!
main.dart 17:3       testFunction.<async>
dart:async           _Completer.completeError
main.dart 4:1        testFunction.<async>
dart:async           Future.Future
main.dart 4:1        testFunction
main.dart 11:26      main.<async>.<fn>
package:stack_trace  Chain.capture
main.dart 10:16      main.<async>

我做错了什么？

推荐答案

是什么版本的Dart和 stack_trace 你在使用吗？在Dart 1.9.0-edge.44028 与 stack_trace 1.2.3 ，删除 console_test 行后，我得到以下输出：

What versions of Dart and stack_trace are you using? On Dart 1.9.0-edge.44028 with stack_trace 1.2.3, after deleting the console_test line, I get the following output:

test.dart 16:3       testFunction.<async>
dart:async           _Completer.completeError
test.dart 17:2       testFunction.<async>
dart:async           Future.Future.microtask
test.dart 7:25       main.<async>.<fn>.<async>
package:stack_trace  Chain.capture
test.dart 5:16       main.<async>

这也值得注意，你不需要使用 Trace。格式与链。你可以使用 Chain.terse ，这也将保留异步间隙。

It's also worth noting that you don't really need to use Trace.format with Chain. You can just use Chain.terse, which will also preserve the asynchronous gaps.

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