Re: [WebIDL] Handling undefined in Overload Resolution Algorithm

On 8/4/11 4:44 AM, Anne van Kesteren wrote:
> On Thu, 04 Aug 2011 02:50:38 +0200, Cameron McCormack <cam@mcc.id.au>
> wrote:
>> Let me know your thoughts.
>
> In general this sounds good to me. Has anyone tested legacy APIs like
> the open() method of XMLHttpRequest to see if you get the same? I sort
> of thought undefined was passed through, but maybe I misremember.

In Gecko, undefined used to be treated as "not specified" for 
XMLHttpRequest.  When we changed to following the current spec (which 
converts undefined to "undefined") we actually ran into compat issues 
with some popular JS libraries that pass undefined for username/password 
explicitly.  For now we're sticking it out, but it sure would be nice to 
not have those compat issues!

-Boris