Bug 157180 – Specifying a longhand property should not serialize to a shorthand property

• Component: CSS
• Status: RESOLVED FIXED

[Antoine Quint]

The CSS spec defines what should happen when serializing a CSS declaration block at http://www.w3.org/TR/cssom-1/#serialize-a-css-declaration-block. In there, the spec says that we should only serialize to a shorthand property if all required longhand properties are specified. So an element with a "style" attribute set to "background-color: green" should not return "green" when querying element.style.background, but "".

[Radar WebKit Bug Importer]

<rdar://problem/26002754>

[Antoine Quint]

Created attachment 277700 [details]
Patch

[Dean Jackson]

Comment on attachment 277700 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=277700&action=review

> Source/WebCore/css/StyleProperties.cpp:389
> +        // We don't have all longhand properties defined as required for the shorthand
> +        // property and thus should not serialize to a shorthand value. See spec at
> +        // http://www.w3.org/TR/cssom-1/#serialize-a-css-declaration-block.
> +        if (!values[i])
> +            return String();

Put this comment inside the if statement, so it doesn't read as applying to everything here.

> LayoutTests/fast/css/no-shorthand-with-incomplete-longhands.html:9
> +var shorthands = { "background": ["background-image: url(foo.png)", "background-position-x: 10px", "background-position-y: 10px", "background-size: cover", "background-repeat-x: no-repeat", "background-repeat-y: no-repeat", "background-attachment: scroll", "background-origin: padding-box", "background-clip: padding-box", "background-color: green"] }

Shouldn't you try a few more shorthands? Like animation, transition, border, margin, etc

[Simon Fraser (smfr)]

Does this regress bug 81737?

[Dean Jackson]

This would cause pasted content to get more verbose inline style.

I think we need a way for editing workflows to keep this behaviour, but allow our Web-facing APIs to be compliant.

[Ryosuke Niwa]

(In reply to comment #5)
> This would cause pasted content to get more verbose inline style.
> 
> I think we need a way for editing workflows to keep this behaviour, but
> allow our Web-facing APIs to be compliant.

I thought we had a different code path for editing?  Specifically, I don't see this patch changing http://trac.webkit.org/browser/trunk/LayoutTests/editing/pasteboard/paste-and-sanitize.html.

[Dean Jackson]

(In reply to comment #6)
> (In reply to comment #5)
> > This would cause pasted content to get more verbose inline style.
> > 
> > I think we need a way for editing workflows to keep this behaviour, but
> > allow our Web-facing APIs to be compliant.
> 
> I thought we had a different code path for editing?  Specifically, I don't
> see this patch changing
> http://trac.webkit.org/browser/trunk/LayoutTests/editing/pasteboard/paste-
> and-sanitize.html.

Great, then I'll go ahead and land it.

[Dean Jackson]

Committed r200357: <http://trac.webkit.org/changeset/200357>