[css-fonts-5] font property uses it's own concept for reset-only sub-properties

[AtkinsSJ]

The definition for font lists properties that are "reset implicitly" rather than using the "Reset-only sub-property" concept from Cascade-5. I assume it was written first? It would be nice to unify those.

Specifically I recently was going to implement font's concept of it generically but couldn't find it used anywhere else. Turns out it is used elsewhere, it just has a different name. 😅

[svgeesus]

Yes these categories were introduced first, to clarify a specific bug in setting font shorthand properties:

• [css-fonts] Should font-palette be reset by the font shorthand? #7832

in accordance with this CSSWG resolution

I agree that harmonization would be good, but Cascade 5 does not seem to cover all the categories (Cascaded Independently is missing) so this needs further discussion and coordination.

@fantasai @mirisuzanne @tabatkins

[mirisuzanne]

My understanding is that properties which cascade independently are not sub-properties, so I'm not sure what it does to define the type of sub-property that behaves as not a sub-property? Is the goal to call out that some props named foo-* are actually longhand sub-properties of foo, while some are independent but still part of the larger foo feature? I don't think I've seen that called out before.

[svgeesus]

My understanding is that properties which cascade independently are not sub-properties, so I'm not sure what it does to define the type of sub-property that behaves as not a sub-property?

Put like that, it seems obvious. The problem was that some implementations were treating properties called font-foo as if they were sub-properties, and so resetting them to initial values when the font shorthand were set. We needed to clarify which were not sub-properties.

I'm fine to add that clarification to Fonts 4, and to link to the Cascade 5 definition for reset-only sub-property.

[AtkinsSJ]

Perfect, thank you!