[whatwg] Questions on error handling in web workers
levin at chromium.org
Wed Jun 15 22:23:03 PDT 2011
On Wed, Jul 15, 2009 at 5:17 PM, Ian Hickson <ian at hixie.ch> wrote:
> On Wed, 15 Jul 2009, Jian Li wrote:
> > I have a couple questions regarding error handling in HTML 5 workers. In
> > the spec, it says "Whenever a runtime script error occurs in one of the
> > worker's scripts, if the error did not occur while handling a previous
> > script error, the user agent must report the error using the
> > WorkerGlobalScope object's onerror attribute.". Does it mean that
> > onerror attribute of WorkerContext would be called? In addition to the
> > errors being thrown?
> The term "report the error" is defined here:
The wording in the Web Workers part of the spec about what to do for onerror
has confused a number of people.
Recently, when asked about it, I thought that it should send through an
ErrorEvent when I was pointed at the spec (even though I had seen this issue
Owen Merkling added a repro case here under that assumption:
Separately, Yury Semikhatsky got it mixed up here:
And a number of us (Jian Li, etc.) were confused about it.
We can see that Ben Turner also found it confusing:
Hopefully, the spec can be clarified in this regard to avoid
incompatibilities and confusion among implementors. One possible
clarification would be a link in the onerror section for Web Workers to
indicate that they use this definition:
> > The spec also says "For dedicated workers, if the error is still not
> > handled afterwards, or if the error occurred while handling a previous
> > script error, the user agent must queue a task to fire a worker error
> > event at the Worker object associated with the worker.". What does it
> > mean by "the error is still not handled afterwards"? Does it mean that
> > the onerror attribute is not set for WorkerContext?
> The term "not handled" is defined here:
> Ian Hickson U+1047E )\._.,--....,'``. fL
> http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
> Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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