Bug 280034 – Page crash in CSSCalcSymbolNode::doubleValue when using channel extracted from relative color syntax into a calc(pow()) expression

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

[P]

Created attachment 472608 [details]
Crash log

Hello,

I've been using the relative color syntax https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_colors/Relative_colors to manipulate the alpha level based on the oklch lightness of a given color.

We have noticed that re-using one of the channel (Lightness in our case, but the same seems to happen for Chroma and Hue) inside a pow() function causes a complete crash of the page.


Here's how to reproduce:
- On Safari 18
- Navigate to https://svelte.dev/repl/ea2f7b1c06644275abaee5247b938a76?version=4.2.19
- Notice the --alpha expression works for the first 4 options
- Notice crash on the bottom 3 options

Attached a crash log of when the issue triggered.

Thanks.

[Alexey Proskuryakov]

rdar://135787066

[Sam Weinig]

Does not reproduce in ToT.

[Sam Weinig]

From the crashlog, I think it is likely this was fixed with the calc() re-write in https://bugs.webkit.org/show_bug.cgi?id=278244 (though I did not bisect to confirm).