1988224 - Enable anchor positioning pref (layout.css.anchor-positioning.enabled) by default on Nightly

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, enhancement)

Description

[Daniel Holbert [:dholbert]]

Filing this bug on setting layout.css.anchor-positioning.enabled to true on Nightly (or perhaps nightly-and-early-beta).

(We can use the dependency field to track [some of] the work that must happen before we can do this. Though also I think this work is tracked via [anchorpositioning:m whiteboard-field-contents, and maybe it's not worth trying to get those milestones to be perfectly reflected/mirrored in the dependency field of this bug.)

Comment 1

[Sebastian Zartner [:sebo]]

Once the pref is flipped, this should be added to https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Experimental_features, the related BCD, and the release notes on MDN and the general release notes.

[Why is this notable]: Feature CSS authors were requesting for a long time and part of Interop 2025.
[Affects Firefox for Android]: yes
[Suggested wording]: Starting with Firefox x, Nightly builds now support CSS anchor positioning, which allows to tether elements together. The anchor-positioned elements can then have their size and position set relative to the size and location of the anchor elements to which they are bound.
[Links (documentation, blog post, etc)]:
https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_anchor_positioning
https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_anchor_positioning/Using

Comment 2

[Jonathan Watt [:jwatt]]

Attachment: Bug 1988224. Enable anchor positioning pref by default on Nightly. r=dshin

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/693bae3ddb6a
https://hg.mozilla.org/integration/autoland/rev/3a515fea615c
Enable anchor positioning pref by default on Nightly. r=dshin,layout-reviewers

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/27fa9dbeb3dc
https://hg.mozilla.org/integration/autoland/rev/2825f78f0370
Revert "Bug 1988224. Enable anchor positioning pref by default on Nightly. r=dshin,layout-reviewers" for causing anchor related wpt failures.

Comment 5

[Serban Stanca [:SerbanS]]

Reverted this because it was causing anchor related wpt failures.

• Revert link
• Push with failures
• Failure Log
• Failure line: TEST-UNEXPECTED-PASS | /html/semantics/popovers/popover-anchor-display-none.tentative.html | Tests that a popover can be anchored to an unrendered element. - expected FAIL

Also, please check these mochitests failures.

• Failure Log

Comment 6

[Jonathan Watt [:jwatt]]

I used separate bugs to fix the random tests in some unexpected places that didn't have the pref enabled for some reason. I'll reland in a few hours if the landings for bug 1924086 look like they're going to stick.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/613f76a02842
https://hg.mozilla.org/integration/autoland/rev/061d3612121c
Enable anchor positioning pref by default on Nightly. r=dshin,layout-reviewers

Comment 8

[Jonathan Watt [:jwatt]]

Attachment: Bug 1988224 - Test changes for anchor positioning pref enabling. r=dshin

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/01ae2110dfcc
https://hg.mozilla.org/integration/autoland/rev/2b58d75df02a
Test changes for anchor positioning pref enabling. r=dshin

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/69a7ea9b3740
https://hg.mozilla.org/integration/autoland/rev/6339c06cd01d
Mark test `the-anchor-attribute-002.tentative.html` as passing.
https://github.com/mozilla-firefox/firefox/commit/2935a9728966
https://hg.mozilla.org/integration/autoland/rev/c7991781a1dc
Update wpt test @ popover-anchor-multicol-display.tentative.html.ini

Comment 11

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/061d3612121c
https://hg.mozilla.org/mozilla-central/rev/2b58d75df02a
https://hg.mozilla.org/mozilla-central/rev/6339c06cd01d
https://hg.mozilla.org/mozilla-central/rev/c7991781a1dc

Comment 12

[Pascal Chevrel:pascalc]

Note added to our Nightly release notes with this wording:

Starting with Firefox 145, Nightly builds now support CSS anchor positioning, which allows to tether elements together. The anchor-positioned elements can then have their size and position set relative to the size and location of the anchor elements to which they are bound.

Thanks