[css-color-4] [css-color-5] compat issues #8943
Description
There are several open issues around css-color-4 and css-color-5.
At the same time vendors are shipping these features and each vendor has it's own set of implementation bugs. Some are just bugs, others where once correct in an older version of the specification.
These aren't minor issues as they surface in very common cases, most notably interpolations with black | white | transparent and some other color in polar color spaces.
These feature are part of interop 2023, so there is extra pressure to ship something that passes WPT today, even if the specification has already changed and WPT is out of date.
Authors are being taught about the issues as if these are intentional features :
Safari
https://developer.apple.com/videos/play/wwdc2023/10121/?time=755
https://chriscoyier.net/2023/05/12/add-opacity-to-an-existing-color/
I am concerned that the incorrect behavior will become so engrained that it becomes impossible to change. I don't have any strong opinions on what is correct or bugged.
I also want to avoid that authors just give up on all the features of css-color-4 and css-color-5 because of these compat issues.
But I don't know who to ping or what is the right thing to do in cases like these.
It's already part of interop 2023, but that only helps if the specification is final and WPT is up to date.
The issue here is that everyone shipped, shipped different things, while the specification is being finalized and WPT is out of date.
I almost miss vendor prefixes for this case 😅
@svgeesus @tabatkins thoughts?
Edit :
More examples :