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Re: [WebIDL] Exceptions

From: Aryeh Gregor <Simetrical+w3c@gmail.com>
Date: Wed, 6 Jul 2011 17:23:06 -0400
Message-ID: <CAKA+Axm=CvEw7h1o9jnUxDAUeZKXHtSxKt=9KhjBY4vsnb-jYw@mail.gmail.com>
To: Anne van Kesteren <annevk@opera.com>
Cc: WebApps WG <public-webapps@w3.org>
On Wed, Jul 6, 2011 at 7:06 AM, Anne van Kesteren <annevk@opera.com> wrote:
> So with Web IDL going to Last Call does this mean that the exception model
> outlined in http://www.w3.org/Bugs/Public/show_bug.cgi?id=10623#c8 is the
> way forward? I.e. we introduce new exception interfaces in DOM Core for all
> the different exception types and update all other specifications that use
> DOM Core to dispatch those exceptions instead (and they are somewhat
> backwards compatible because they inherit from DOMException and therefore
> still have the code member).
>
> I guess there is no particular rush on this; I am mainly wondering whether
> other editors are aware of this change and agree with it.

The thing I don't like about this proposal is that it encourages
authors to use "e instanceof IndexSizeError" or similar.  This will
work 98% of the time and then fail in an extremely mysterious way when
multiple globals are involved.  All you need is the exception to be
thrown by something in an iframe for whatever reason.

Moreover, I don't even think behavior in that case is defined.  If I
call foo.appendChild(bar) and it throws, is the exception from the
window where the method was called, or the one foo is associated with,
or the one bar is associated with?  Browsers other than Gecko seem to
agree it's the one foo is associated with
(<http://software.hixie.ch/utilities/js/live-dom-viewer/saved/1064>),
and Gecko is just buggy, but is this specced anywhere?  I don't see it
in DOM Core.

I don't see why we need the extra classes.  What's the advantage over
just adding the .name attribute, or something equivalent, and not
adding new classes?  Just consistency with ES, or something else too?
Received on Wednesday, 6 July 2011 21:23:53 GMT

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