Need a global error handler primitive in dart2js.

[floitschG]

We need a way to set the global error-handler. For now just having a private dart2js specific implementation is good enough. We can then provide a public API on top of it.

Also see issue #9273 and issue #9012.

[floitschG]

Marked this as blocking #5958.

[floitschG]

Added some comments on what we want to issue #9273 (the VM counterpart of this bug).

[kasperl]

Added this to the Later milestone.

[kasperl]

Added TriageForM5 label.

[kasperl]

Removed TriageForM5 label.

[kasperl]

Removed this from the Later milestone.
Added this to the M7 milestone.

[kasperl]

Set owner to @kasperl.

[kasperl]

Removed this from the M7 milestone.
Added this to the M8 milestone.

[DartBot]

This comment was originally written by @bjornm

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I cannot find a uniform way to catch all unhandled errors. I see unhandled errors arising in the following situations:

a) inside main()
b) when invoking async closures (futures, timers etc)
c) when handling a browser event
d) in javascript code on page (called from dart, or running by itself)

The RootZone seems to be able to deal with some of these cases but it lacks documentation. I can't seem to be able to override the default behavior for unhandled errors?

For now, I've resorted to listening to the window.addEventListener('error'). However, when the AsyncErrors bubble this far, the trace is lost due to wrapException():

Uncaught Illegal argument(s): foobar Instance of 'ErrorEvent' Error
    at Object.wrapException (studio.dart.js:2706:13)
    at _rootHandleUncaughtError__closure.call$0 (studio.dart.js:7638:13)
    at Closure$0._asyncRunCallback as call$0
    at TimerImpl_internalCallback0.call$0 (studio.dart.js:2384:21)
    at invokeClosure_closure.call$0 (studio.dart.js:3649:27)
    at _IsolateContext.eval$1 (studio.dart.js:1700:21)
    at Object._callInIsolate (studio.dart.js:1450:24)
    at invokeClosure (studio.dart.js:2847:14)
    at studio.dart.js:2867:106

 As a workaround I'm overriding dartPrint() so I can grab the original stackTrace written by the RootZone error handler for later processing. But it would be nice with a cleaner way to do this.

[floitschG]

The following should capture all errors.

main() {
  runZoned(() { <original_main> }),
           onError: (error, stackTrace) { <deal with error> })
}

We are also planning to provide other means to deal with uncaught errors, by sending control-messages to the isolate.

[kasperl]

Added Accepted label.

[kasperl]

Set owner to @floitschG.

[kasperl]

Removed this from the M8 milestone.
Added this to the 1.6 milestone.

[kasperl]

Removed this from the 1.6 milestone.
Added Oldschool-Milestone-1.6 label.

[kasperl]

Removed Oldschool-Milestone-1.6 label.

[lrhn]

Zones is the solution to capturing errors.

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Added AssumedStale label.