[mediaqueries-5] duplication of `forced-colors: active` and `prefers-contrast: forced`

[cookiecrook]

[mediaqueries-5] duplication of forced-colors: active and prefers-contrast: forced

Breaking this discussion out of the large mega thread in #2943.

I believe these statements are true.

1. AFAICT, forced-colors: active and prefers-contrast: forced are exact duplications of each other.
2. I am only aware of one implementation of forced colors: on Windows.
3. forced-colors is already implemented in Edge (and possibly in the Chrome HC extension.)

Opinions:

• I'm not sure why two properties are needed. I think I'd heard both that the forced value is intended as a replacement for the forced-colors media feature, and I've also heard that these are intended to be complementary and co-exist. Which is it, and why?
• Since there is only one implementation (Windows), I worry that shoehorning a single forced value into prefers-constrast is unnecessarily limiting. Another platform (iOS, Mac, ChromeOS, Android, Linux) may support a different forced mode in the future, and forced-colors would be easier to extend.

Editorial: prefers-contrast: forced cross-link to forced-colors: active an confirms the duplication. If both are kept, the reciprocal link and explanatory prose should be added, too.

[cookiecrook]

Even though I'm a WG member, I'm not able to add the requested labels. Is that intentionally limited to full editors?

[astearns]

Nope, it's just a manual step for us to add people to the right team. You should be good now.

[frivoal]

Whether or not its the right conclusion is a separate question, but the current idea is:

They are indeed the exact same thing. We wish we had though of defining it as prefers-contrast: forced first, but we didn't, so MS shipped force-color: active already. We thought we still liked prefers-contrast: forced better, so we defined that, but since forced-colors: active shipped, we're keeping it as well for compat reasons. The fact that one is the desired syntax, and the other is the legacy alias isn't currently clear in the spec, but an editorial cleanup should make that more obvious.

So, with that in mind, I think we can take 3 stances:

1. I think all is all is fine, just do the editorial clean up to make it clear why there's two.
2. I agree that prefers-contrast: forced is the better design, but the benefit isn't strong enough to justify a "good syntax" and "legacy syntax", so we should revert the decision taken in [css-color-adjust-1][mediaqueries-5] Fold forced-colors and prefers-contrast? #3856 to add forced to prefers contrast.
3. I disagree that prefers-contrast: forced is the better design. Keeping forced colors separate from contrast preferences is desirable, regardless of compat. On that basis, we should revert the decision taken in [css-color-adjust-1][mediaqueries-5] Fold forced-colors and prefers-contrast? #3856 to add forced to prefers contrast.

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My stance is (1), and as the spec's Editor, I'll do the editorial clean-up to at least make it clear what the current situation is.

I believe your stance is closer to (3). I'd suggest holding off just a bit to see if the clean-up I'm about to do makes things better in your opinion. If it doesn't, it's probably worth re-reading #3856 (I'd say from the top up to and including the teleconf minutes of June 11, after that it goes into a number of tangeants, most of which are answered by #2943 or by the editorial clean-up I'm about to make), and responding to the points that were made in favor of the resolution that was taken then.

[cookiecrook]

My stance is partially 2 (added 2b below) and fully 3.

2b. Regardless of which syntax is better, there is only one platform that supports this feature and the current syntax is sufficient to cover that platform. Therefore, the benefit isn't strong enough to justify a syntax duplication. If future platform features require additional syntax changes, it would be better to wait until we know what those are.

3. I disagree that prefers-contrast: forced is the better design. Keeping forced colors separate from contrast preferences is desirable, regardless of compat. On that basis, we should revert the decision taken in [css-color-adjust-1][mediaqueries-5] Fold forced-colors and prefers-contrast? #3856 to add forced to prefers contrast.

Yes to this, too.