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From Alex Harui <aha...@adobe.com>
Subject Re: Why can't we try-catch errors thrown from event handlers?
Date Thu, 26 Jun 2014 15:49:22 GMT
No objection from me.  For simple, easily reversible code changes, I just
do them and let folks object when they see the commit email.  Otherwise, I
try to let an email sit about 24 hours, then go and do it.  For big
things, I try to warn folks up front as I start on it.

On 6/26/14 8:35 AM, "Mihai Chira" <mihai.chira@gmail.com> wrote:

>Cool, thanks for the explanation. I'm happy to take this[1] on, if we
>agree it's worth doing (I definitely think it is).
>[1] https://issues.apache.org/jira/browse/FLEX-34385
>On 26 June 2014 05:49, Alex Harui <aharui@adobe.com> wrote:
>> On 6/25/14 4:53 AM, "Mihai Chira" <mihai.chira@gmail.com> wrote:
>>>Today I stumbled upon what feels like strange behaviour. In short, if
>>>there's an Error thrown in an event listener, it won't be caught in
>>>the catch block of the code that dispatched the event. Instead, it
>>>will be dispatched by the uncaughtErrorEvents property of LoaderInfo.
>>>(See the code below.)
>> Yep, that is expected behavior.  I believe it has to do with the
>> stack/activationObject getting lost in the player's dispatchEvent code.
>> I
>> think there are other cases where, if you call into the player and the
>> player calls more ActionScript that you can't catch errors in that AS.
>>>Does this imply that event dispatching is asynchronous? Despite that
>>>the stack traces always include the event dispatching, and thus seem
>>>to imply it's synchronous? Or just the fact that it happens at a lower
>>>level (within the C++ code of the flash player, perhaps?) impacts
>>>try-catch blocks?
>> No, event dispatching is synchronous.
>>>In any case, I think it would really help if we updated the
>>>documentation under LoaderInfo.uncaughtErrorEvents [1] and the
>>>description of the UncaughtErrorEvents class [2] to include this.
>> Well, we can't since that's a player API.   UIComponent does wrap
>> dispatchEvent so you could add some documentation there.  Or we could
>> start a Wiki page of "Nasty Issues".  You are now a committer.  Go for
>> -Alex

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