I'm very slightly worried about the cases which we seem to accept, but the latest on the CSSWG thread suggests we should disallow. Namely, @container and @page. How sure are you that changing those to be invalid in the future, to follow the latest CSSWG decisions, will not cause compat problems?
On Tuesday, May 13, 2025 at 6:37:14 AM UTC+9 Mike Taylor wrote: > LGTM1 > On 5/9/25 9:47 AM, Rune Lillesveen wrote: > > Contact emails futh...@chromium.org, se...@chromium.org > > Explainer > https://github.com/w3c/csswg-drafts/blob/main/css-values-5/tree-counting-explainer.md > > Specification https://drafts.csswg.org/css-values-5/#tree-counting > > Design docs > > https://github.com/w3c/csswg-drafts/blob/main/css-values-5/tree-counting-explainer.md > > Summary > > sibling-index() and sibling-count() can be used as integers in CSS > property values to style elements based on their position among its > siblings, or the total number of siblings respectively. These functions can > be used directly as integer values, but more interestingly inside calc() > expressions. Example: li { margin-left: calc(10px * sibling-index()); } > > > Blink component Blink>CSS > <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3ECSS%22> > > TAG review https://github.com/w3ctag/design-reviews/issues/1068 > > TAG review status Issues addressed > > Risks > > > Interoperability and Compatibility > > None > > > *Gecko*: No signal ( > https://github.com/mozilla/standards-positions/issues/1194) > > *WebKit*: No signal ( > https://github.com/WebKit/standards-positions/issues/471) > > *Web developers*: Positive > > https://css-tricks.com/how-to-wait-for-the-sibling-count-and-sibling-index-functions/ > https://chriscoyier.net/2023/11/29/element-indexes/ > https://kizu.dev/tree-counting-and-random/ > > *Other signals*: > > WebView application risks > > Does this intent deprecate or change behavior of existing APIs, such that > it has potentially high risk for Android WebView-based applications? > > None > > > Debuggability > > Basic support out-of-the box. With the value debugger (crbug.com/396080529) > shipped, evaluating sibling-index()/sibling-count() into a <number> should > work out-of-the-box. > > > Will this feature be supported on all six Blink platforms (Windows, Mac, > Linux, ChromeOS, Android, and Android WebView)? Yes > > Is this feature fully tested by web-platform-tests > <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md> > ? Yes > > https://wpt.fyi/results/css/css-values/tree-counting > > > Flag name on about://flags #enable-experimental-web-platform-features > > Finch feature name CSSSiblingFunctions > > Rollout plan Will ship enabled for all users > > Requires code in //chrome? False > > Tracking bug https://crbug.com/40282719 > > Sample links > https://codepen.io/argyleink/pen/KwKXPYW > > Estimated milestones > Shipping on desktop 138 > DevTrial on desktop 133 > Shipping on Android 138 > DevTrial on Android 133 > Shipping on WebView 138 > > Anticipated spec changes > > > There is an open issue[1] about what tree counting functions mean outside > of element contexts. The plan is to handles tree counting functions like > this for the relevant @-rules when shipping: > > > - @font-face: invalid at parse time > > - @font-palette-values: invalid at parse time > > - @property: accepted at parse time (the values are strings), but since > these values are not computationally independent when evaluated, they will > be dropped as initial values. > > - @counter-style: invalid at parse time > > - @container: the container is in an element context and tree counting > functions are evaluated as such > > - @page: accepted at parse time and evaluated against the root element > > - @media (in query value): invalid at parse time > > > Shipping a different specified behavior for tree counting functions in > these contexts (to what the issue is resolved to later) should be > straightforward. > > > [1] https://github.com/w3c/csswg-drafts/issues/10982 > > Link to entry on the Chrome Platform Status > https://chromestatus.com/feature/6225478530367488?gate=6089164107546624 > > Links to previous Intent discussions Intent to Prototype: > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/67c70d35.2b0a0220.36af1.0007.GAE%40google.com > > This intent message was generated by Chrome Platform Status > <https://chromestatus.com/>. > -- > Rune Lillesveen > > -- > You received this message because you are subscribed to the Google Groups > "blink-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to blink-dev+unsubscr...@chromium.org. > To view this discussion visit > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CACuPfeTS2BYBs8yqpNXnJa5tAMwPar4X3jOPtLddMydRX0oEoA%40mail.gmail.com > > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CACuPfeTS2BYBs8yqpNXnJa5tAMwPar4X3jOPtLddMydRX0oEoA%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > -- You received this message because you are subscribed to the Google Groups "blink-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+unsubscr...@chromium.org. To view this discussion visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/f4d661c8-78cd-46f5-9436-4bc45934c25fn%40chromium.org.
