[css-fonts-4] “Font fetching requirements” doesn’t fully specify necessary requirements

[sideshowbarker]

The Font fetching requirements section of the CSS Fonts 4 spec doesn’t fully specify the requirements necessary for a UA to actually perform a font-fetch request and do something with the response.

https://drafts.csswg.org/css-fonts-4/#font-fetching-requirements

A patch (#5838) was recently merged that I wrote to add a part of the necessary requirements; but even with that change in place, there are still missing pieces:

• The spec text defines how to construct a request but should also explicitly set the request mode to cors.
• The spec doesn’t define what to do with the request; it needs to have something like, “Let response be the result of ∞fetching∞ request, where ∞fetching∞ links to the fetch algorithm in the Fetch spec.
• The spec doesn’t define what to to with the response it gets back.

@annevk

[svgeesus]

The spec doesn’t define what to to with the response it gets back.

Could you point to an example of a similar spec which does define what to do with the response?

[sideshowbarker]

Could you point to an example of a similar spec which does define what to do with the response?

Among CSS specs, in the CSSOM spec, the Fetching CSS style sheets algorithm:

https://drafts.csswg.org/cssom/#fetching-css-style-sheets

…and the call points for that in Requirements on User Agents Implementing the xml-stylesheet processing instruction:

https://drafts.csswg.org/cssom/#ref-for-fetch-a-css-style-sheet

…and in Requirements on User Agents Implementing the HTTP Link Header:

https://drafts.csswg.org/cssom/#ref-for-fetch-a-css-style-sheet①

[noamr]

I believe this is potentially fixed by #6715