Bug 285142 – Fix font-style-interpolation.html WPT to expect `oblique 0deg` instead of `normal`

• Status: RESOLVED
• Resolution: FIXED
• Component: CSS

[Karl Dubost]

On Bug 258510, failures were fixed by Antoine.
https://wpt.fyi/results/css/css-fonts/animations/font-style-interpolation.html?label=master&label=experimental&aligned&q=font-style

Some asserts are failing.
assert_equals: expected "normal " but got "oblique 0deg "

It was regressed by
https://github.com/WebKit/WebKit/commit/ea0e8115cda32876124dc327f488b465e7041b0d

[Alexey Proskuryakov]

> It was regressed by
> https://github.com/WebKit/WebKit/commit/ea0e8115cda32876124dc327f488b465e7041b0d

That's https://commits.webkit.org/283851@main

[Radar WebKit Bug Importer]

<rdar://problem/142226848>

[Tim Nguyen (:ntim)]

You could fix this by making ComputedStyleExtractor return `CSSPrimitiveValue::create(CSSValueNormal)` when the angle is 0deg:
 https://searchfox.org/wubkat/rev/334d5acc1496f43ce5ffbc3abc190f145f9add1a/Source/WebCore/css/ComputedStyleExtractor.cpp#2557-2563

[Sam Weinig]

My reading of the spec is that 0deg oblique is correct.

Per https://drafts.csswg.org/css-fonts-4/#font-weight-prop, Animation Type is spec'd to "by computed value type;normal animates as oblique 0deg".

[Tim Nguyen (:ntim)]

(In reply to Sam Weinig from comment #4)
> My reading of the spec is that 0deg oblique is correct.
> 
> Per https://drafts.csswg.org/css-fonts-4/#font-weight-prop, Animation Type
> is spec'd to "by computed value type;normal animates as oblique 0deg".


Indeed: https://github.com/w3c/csswg-drafts/issues/2505

The computed value should be left alone, and only the interpolation should use `oblique 0deg`.

https://drafts.csswg.org/css-fonts-4/#font-style-prop

We should probably update the WPT then.

[Tim Nguyen (:ntim)]

Arguably `normal` is the shorter serialization for `oblique 0deg` so my suggested change might be reasonable, but more as a general serialization rule rather than an interpolation specific one.

[Sam Weinig]

Updating the tests makes the most sense to me.

[Tim Nguyen (:ntim)]

Pull request: https://github.com/WebKit/WebKit/pull/38475

[Tim Nguyen (:ntim)]

Submitted web-platform-tests pull request: https://github.com/web-platform-tests/wpt/pull/49892

[Tim Nguyen (:ntim)]

Pull request: https://github.com/WebKit/WebKit/pull/38481

[EWS]

Committed 288388@main (4cb01b5b4562): <https://commits.webkit.org/288388@main>

Reviewed commits have been landed. Closing PR #38481 and removing active labels.