1377414 - Gecko treat 'none' as a predefined counter style, while stylo treat it as a separate keyword value

Status: NEW

(Core :: CSS Parsing and Computation, enhancement, P5)

Description

[Xidorn Quan [:xidorn] UTC+10]

This is a recent spec change from w3c/csswg-drafts#1295.

The only effective difference as far as I can see is that "system" and "fallback" descriptors of @counter-style rule would reject 'none' as a valid value, which is currently valid in Gecko.

Also, there is some inconsistency from this currently, that the counter style rule object is still implemented in Gecko side, which means it still uses the grammar from Gecko. So although the parsing (implemented in Servo) would reject 'none' in those cases, if you set it via CSSOM, that would still be accepted.

This inconsistency would be fixed in the future after we drop the current style system.

This shouldn't cause any real issue, but it is still a behavior change we may want to track.

Comment 1

[Chris Mills [:cmills]]

Marking as part of documentation plan for intentional stylo differences

Comment 2

[Chris Mills [:cmills]]

Documented: 

https://developer.mozilla.org/en-US/docs/Web/CSS/@counter-style#Quantum_CSS_notes

Is this description OK?

Comment 3

[Xidorn Quan [:xidorn] UTC+10]

That description is opposite. Gecko allows "none" in those places, while Stylo doesn't. The spec was updated recently to reflect Stylo's behavior.

Comment 4

[Chris Mills [:cmills]]

(In reply to Xidorn Quan [:xidorn] UTC+10 from comment #3)
> That description is opposite. Gecko allows "none" in those places, while
> Stylo doesn't. The spec was updated recently to reflect Stylo's behavior.

Thanks for catching this; I've fixed it now.

Comment 5

[Firefox Bug Husbandry Bot]

https://wiki.mozilla.org/Bug_Triage/Projects/Bug_Handling/Bug_Husbandry#Move_fix-optionals