[css-values-5] Should random() function caching key work over used values?

[nt1m]

Right now, it works over used values as specified by https://drafts.csswg.org/css-values-5/#random-caching , but that leads to weird behavior where resizing a window will cause new random values to be computed when viewport units are used: https://bugs.webkit.org/show_bug.cgi?id=287918

cc @tabatkins @weinig @smfr

[Loirooriol]

<length> is absolutized to canonical units at computed-value time, so basing caching on computed values would have the same problem. And basing it on specified values seems weird?

[nt1m]

#11742 would be one solution to this.

[tabatkins]

Putting #11742 to the side for now, I don't have a real opinion on how this is resolved. The caching key is just constructed from the arguments to make it more likely that it's page-unique by default.

I don't think we really have a defined notion of "equality" for specified values. In theory we could make it based on token streams or source text, if we really wanted it to be stable?