[csswg-drafts] [css-variables] CSS wide keywords in custom properties with dependencies (#9131)

emilio has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-variables] CSS wide keywords in custom properties with dependencies ==
I was investigating a [Firefox bug](https://bugzilla.mozilla.org/show_bug.cgi?id=1843783) about custom properties with css-wide keyword fallbacks.

The following test-case ([live](https://bug1843783.bmoattachments.org/attachment.cgi?id=9346498)) renders differently in Chromium and Safari. I can explain the difference, I believe.

Safari seems to first figure out what declarations apply, then you resolve dependencies between the values, and treat revert-layer as invalid at computed value time. This is similar to how longhands work.

Chromium seems to do something different, where their dependency-cycle detection also seems to deal with `revert-layer` somehow.

To me Safari's behavior seems easier to understand, but I might be biased because that's how Gecko implements custom-properties too. I _think_ Chromium's behavior is more correct tho, but a clarification on the spec and sanity-checking my understanding of the situation would be great.

@mdubet / @andruud is my understanding above right?

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/9131 using your GitHub account


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Received on Monday, 31 July 2023 15:58:58 UTC