Intent to Ship: Rename position-try-options to position-try-fallbacks

{NOTE: this is a replacement of this chromestatus, which has the wrong feature type and cannot be changed.}

Contact emails

[email protected], [email protected]

Explainer

None

Specification

https://github.com/w3c/csswg-drafts/issues/10395#issuecomment-2192127524

Summary

The CSSWG resolved to rename this property, because "fallbacks" more accurately describes what this property controls. The word "options" is a bit deceiving, since the styles outside of `position-try` blocks will be tested first, and if they result in a layout that fits within the containing block, none of the "options" will get used. So "fallbacks" is a better word to describe this behavior. https://github.com/w3c/csswg-drafts/issues/10395#issuecomment-2192127524

Blink component

Blink>CSS

TAG review

None

TAG review status

Not applicable

Risks

Interoperability and Compatibility

This is a name change, which will result in the old name no longer functioning. So there is a risk of breakage. However, the anchor positioning feature was very recently shipped, and does not have implementation in other browsers. So we feel the risk is quite small currently, but will grow over time. Given that, we'd like to rename this property ASAP to avoid the risk getting too large. The use counter is currently quite low, around 0.01% in June: https://chromestatus.com/metrics/css/timeline/popularity/784 An HTTP Archive search was performed, which showed that almost all usage comes from one Shopify CSS file (`spec-and-compare.css`), and we intend to reach out to Shopify (or hope for a response from one very special Blink API owner) to make sure this will not break Shopify.

On Wed, Jul 10, 2024 at 6:34 PM Mason Freed <[email protected]> wrote:

{NOTE: this is a replacement of this chromestatus, which has the wrong feature type and cannot be changed.}

Contact emails

[email protected], [email protected]

Explainer

None

Specification

https://github.com/w3c/csswg-drafts/issues/10395#issuecomment-2192127524

Summary

The CSSWG resolved to rename this property, because "fallbacks" more accurately describes what this property controls. The word "options" is a bit deceiving, since the styles outside of `position-try` blocks will be tested first, and if they result in a layout that fits within the containing block, none of the "options" will get used. So "fallbacks" is a better word to describe this behavior. https://github.com/w3c/csswg-drafts/issues/10395#issuecomment-2192127524

Blink component

Blink>CSS

TAG review

None

TAG review status

Not applicable

Risks

Interoperability and Compatibility

This is a name change, which will result in the old name no longer functioning. So there is a risk of breakage. However, the anchor positioning feature was very recently shipped, and does not have implementation in other browsers. So we feel the risk is quite small currently, but will grow over time. Given that, we'd like to rename this property ASAP to avoid the risk getting too large. The use counter is currently quite low, around 0.01% in June: https://chromestatus.com/metrics/css/timeline/popularity/784 An HTTP Archive search was performed, which showed that almost all usage comes from one Shopify CSS file (`spec-and-compare.css`), and we intend to reach out to Shopify (or hope for a response from one very special Blink API owner) to make sure this will not break Shopify.

Have you had a chance to investigate what a breakage looks like by checking the sites using the feature?

Have you had a chance to investigate what a breakage looks like by checking the sites using the feature?

More specifically, as discussed previously, this usage is coming from a 3P app that merchant sites install and that Shopify has no direct control over. Have you reached out to the app's authors? Have you tried to see if it gets broken by this change? 

I think this rename is fairly safe, but I want to make sure that we're planning on shipping it with a flag that would be able to undo the behavior (a killswitch). I assume having two flags, one to add a new flag and one to remove the old flag is the easiest way to do that. WDYT?