Bug 96844 – Sign in front of keyframe selector causes the subsequent ruleset to be ignored

• Component: CSS
• Status: RESOLVED FIXED

[Simon Fraser (smfr)]

A keyframes rule like:

@-webkit-keyframes fade {
    -10% { background-color: blue; }
    100% { background-color: green; }
}

will cause stylesheet parsing to abort.

I don't understand why, since the 'key' production is using PERCENTAGE, which is a <number>, which should accept signs.

I think this is a problem in the lexer code.

[Simon Fraser (smfr)]

Created attachment 164254 [details]
Testcase

[Simon Fraser (smfr)]

Looks like dashes are only handled in NthChildMode. Maybe we need a mode for keyframe selectors.

[Takashi Sakamoto]

According to the spec: http://dev.w3.org/csswg/css3-animations/#keyframes,
"If a keyframe selector specifies negative percentage values or values higher than 100%, then the keyframe will be ignored."

So I think, the attached TestCase does not work.

Best regards,
Takashi Sakamoto

(In reply to comment #0)
> A keyframes rule like:
> 
> @-webkit-keyframes fade {
>     -10% { background-color: blue; }
>     100% { background-color: green; }
> }
> 
> will cause stylesheet parsing to abort.
> 
> I don't understand why, since the 'key' production is using PERCENTAGE, which is a <number>, which should accept signs.
> 
> I think this is a problem in the lexer code.

[Simon Fraser (smfr)]

(In reply to comment #3)
> According to the spec: http://dev.w3.org/csswg/css3-animations/#keyframes,
> "If a keyframe selector specifies negative percentage values or values higher than 100%, then the keyframe will be ignored."

That's not the point. A minus sign in front of the keyframe selector causes the entire rest of the stylesheet to be ignored. That's obviously wrong.

[Glenn Adams]

Created attachment 166351 [details]
Better test case.

This test case shows that it is the next (ruleset) statement that is being skipped, and not the entire remaining stylesheet.

[Glenn Adams]

Created attachment 166375 [details]
Patch

[Simon Fraser (smfr)]

Comment on attachment 166375 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=166375&action=review

> Source/WebCore/ChangeLog:8
> +        Upon encountering negative percentage, ignore only subsequent block.

I don't think we should ignore the block at the parsing level. This is totally valid CSS; we just need to handle keyframes outside of 0-100% in the code.

[Glenn Adams]

Created attachment 166381 [details]
Patch

[Glenn Adams]

Comment on attachment 166381 [details]
Patch

address comment #7

[WebKit Review Bot]

Comment on attachment 166381 [details]
Patch

Clearing flags on attachment: 166381

Committed r130007: <http://trac.webkit.org/changeset/130007>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.