1840781 - [css-nesting] Ship CSS Nesting

Status: VERIFIED FIXED

(Core :: CSS Parsing and Computation, task)

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1840781 - [css-nesting] Enable by default. r=#style,#layout

After the pending test fixes (bug 1843349) we only fail tests due to two
reasons:

• :has() being unsupported. Not related to the feature itself.

• The nesting selector being inside another (invalid) forgiving
  selector, e.g. :is(!&) not being preserved.

The later is pretty much in edge-case-land, and I think
https://github.com/w3c/csswg-drafts/issues/8356 would be more consistent
rather than doing it only when an & is found (which is very very weird).

So I wouldn't want to block on that. Let's let it ride the trains.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/88d3fbc7589e
[css-nesting] Enable by default. r=boris

Comment 3

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/88d3fbc7589e

Comment 5

[Noemi Erli[:noemi_erli]]

Verified in today's beta simulation push

Comment 6

[Ryan VanderMeulen [:RyanVM]]

Should we call this out in the Fx117 relnotes?

Comment 7

[Emilio Cobos Álvarez (:emilio)]

Release Note Request (optional, but appreciated)
[Why is this notable]: Implements improved nesting behavior, see the dev-platform thread for details
[Affects Firefox for Android]: Yes
[Suggested wording]: Support for improved CSS nesting is enabled by default. We could go into more technical details I guess but the email thread is probably better for that.
[Links (documentation, blog post, etc)]: Probably https://groups.google.com/a/mozilla.org/g/dev-platform/c/2oBSRgIRf80 is ok? Apparently MDN doesn't have great documentation for this?

Comment 8

[Ryan VanderMeulen [:RyanVM]]

Added to the Fx117 relnotes.

Comment 9

[Dave Letorey]

A number of pages have been created:

• /en-US/docs/Web/CSS/CSS_nesting
• /en-US/docs/Web/CSS/Nesting_selector
• /en-US/docs/Web/CSS/CSS_nesting/Using_CSS_nesting
• /en-US/docs/Web/CSS/CSS_nesting/Nesting_and_specificity
• /en-US/docs/Web/CSS/CSS_nesting/Nesting_at-rules

Added to the release notes for Firefox 117:

• /en-US/docs/Mozilla/Firefox/Releases/117

Updated the CSSRef.ejs page in Yari to show the new pages in Guides

Associated Pull Requests

• Content PR
• Browser Compat Data PR
• Yari PR