Bug 296134 – REGRESSION(296337@main): currentcolor used in custom property no longer resolves correctly

• Component: New Bugs
• Status: RESOLVED FIXED

[Sam Weinig]

Created attachment 476073 [details]
Test Case

Benoît Rouleau (@benface) pointed out in https://github.com/w3c/csswg-drafts/issues/10371#issuecomment-3082053452 that we have a regression from 296337@main where `currentcolor` is no longer resolved correctly for rendering when used in a custom property:

https://codepen.io/benface/pen/KwddNvX

(Further simplified test case attached)

[Sam Weinig]

The issue is that during style building, rather than using the parsed content in the `Style::CustomProperty`, which has the correct "currentcolor" Style::Color in it, what we do is fall into a code path that calls, `Style::CustomProperty::tokens()`, and then re-parses the color.

`CustomProperty::tokens()` uses `CustomProperty::propertyValueSerialization()`, but with no RenderStyle available, we end up serializing to black by default.

Ideally we would just use the already parsed value in the CustomProperty, but I don't know enough about this code to understand why we don't.

So, barring that, I can see two solution:

1. Store the original tokens in the CustomProperty at creation so that we have exactly what is needed.
2. Add additional serialization logic needed for this case back.

I think 1 would less error prone.

[Sam Weinig]

I don't think this would be a trivial direct revert, as there has been a bit that has built on the serialization changes this provided.

[Benoît Rouleau]

Thank you for filing this! 🙏 This bug is breaking this website in production: https://thegraph.com. Notice the icons in the header are now black instead of white.

[Radar WebKit Bug Importer]

<rdar://problem/156076502>

[Sam Weinig]

Ok, given this is a real world regression, going to try to do a partial revert, and just do some name changing to make things work.

[Sam Weinig]

Pull request: https://github.com/WebKit/WebKit/pull/48197

[EWS]

Committed 297600@main (6496fbaca29d): <https://commits.webkit.org/297600@main>

Reviewed commits have been landed. Closing PR #48197 and removing active labels.