Re: [css3-background] clarify which properties in this module apply to ::first-letter and ::first-line

On 04/03/2012 10:39 AM, Brian Manthos wrote:
> It's more than that.
>
> The requirement to NOT allow it for box-shadow was explicitly stated.  Has the due diligence been done to research why that was the case?

As I said, we attempted to align box-shadow with the CSS2.1 conformance
requirements on borders because, like borders, it delineates the box.
The result was wrong for two reasons:
   a) The reason borders were excluded in 2.1 wasn't because they delineate
      the box (as backgrounds also do this), but because they affect layout.
   b) Our wording forbid 'box-shadow' on ::first-line, whereas 2.1 allows
      borders to apply through the "may apply other properties" clause.

> How many pages on the planet would be broken by changing that?

I'd wager none. 'box-shadow' on ::first-line doesn't seem like an especially
common thing to try.

> Seems like an another post-CR arbitrary change to CSS3.

We're supposed to correct errors. Given CSS2.1 allows UAs to apply more
than the properties listed, and the CSSWG never explicitly discussed
and resolved on this, I consider outright forbidding 'box-shadow' on
::first-line to be an error.

Whether we allow it or not depends on the CSSWG's resolution on how to
handle ::first-line properties going forward: on whether we choose to
make ::first-line as permissive as possible or as restricted as possible.
And if we intend for Level 4 to require box-shadow to ::first-line, then
we certainly should relax the restriction in L3 so that it is not
non-conforming.

> There's a larger story here also:  Don't put conformance requirements into the spec that are frivolous.  It's a waste of implementer resources to enforce requirements that you end up casually waving off later.

Nobody's perfect. You don't release software free of bugs; neither do
we release specs free of issues. Of course we try, but it's unrealistic
to expect we will succeed.

~fantasai

Received on Tuesday, 3 April 2012 19:09:17 UTC