[whatwg] Error propagation in child workers

Ian Hickson ian at hixie.ch
Sat Dec 27 15:23:02 PST 2008

On Sat, 27 Dec 2008, ben turner wrote:
> I'm implementing these latest changes and it looks like there are some 
> typos in this edit:
> - The ErrorEvent interface has a 'fileno' property, not a 'lineno' 
> property as mentioned elsewhere. I believe it should be 'lineno'.
> - There's a stray 'span>' before 'queue a task'.

Oops. Fixed. Thanks.

> Then I have a few more observations and questions:
> 1. The part about the initial value of onerror being undefined... I 
> understand why you'd want that, but we don't have a similar requirement 
> for onmessage. Should we?

Historically, onerror is the only attribute that acts like this on Window. 
I agree that it is kind of weird, but I think we're better off just 
leaving it like that -- weirdness is bad enough, but inconsistent 
weirdness is even worse.

> 2. Should we allow multiple error handlers in the scope via 
> addEventListener? Or should there only ever be one?

How does it work with Window error reporting?

> 3. Currently the mozilla implementation also uses the error event 
> mechanism for parse errors in the worker script, and these errors will 
> be impossible to trap in the scope's onerror handler. I don't really 
> care about that but I wanted to mention it in case someone else does.

I think that's ok. Workers are equivalent to <script> blocks with a single 
<script>, and the same limitation applies there.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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