1975531 - Change `&` behaviour inside `@scope` block as per spec resolution

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, enhancement)

Description

[David Shin[:dshin]]

Currently & behaves as if copy and pasting the scope-start-selector.
As per discussion logged in See Also, this is probably going to change:

• Current suggested resolution is :where(:scope), like the implicitly inserted :scope.
• There's going to be another discussion in a week's time to discuss alternatives.

Explainer here

Comment 1

[David Shin[:dshin]]

Resolution was made to keep the suggested change, so will be working on this.

Comment 2

[David Shin[:dshin]]

Attachment: Bug 1975531: Change behaviour of parent selector in @scope to be :where(:scope). r=#style

... Rather, just use the implicit scope selector, which is effectively the same
thing. This is done as per the recent CSSWG resolution [1].

[1] https://github.com/w3c/csswg-drafts/issues/9740

Comment 3

[David Shin[:dshin]]

Attachment: Bug 1975531: Adjust web-platform-tests for & being replaced by :where(:scope) in @scope. r=#style

This is as per the CSSWG resolution [1].

• scope-invalidation.html: Adjust for & no longer inheriting scope start
  selector's specificity.
• scope-specificity.html: Now equate @scope(#main) { & .b {} } with
  :where(#main) .b in terms of specificity.
• scope-nesting.html:
  • test_nest_scope_end: Now behaves identically to
    test_nest_scope_end_implicit_scope
  • test_inner_nest: Now behaves identically to
    test_parent_in_pseudo_scope
  • test_parent_pseudo_in_nested_scope_end: Removed; there's no equivalence
    with implicit :scope
  • test_insert_ampersand_rule_within_scope: Insert the selector using &
    before and after the selector using implicit scope selector, since
    order of apperance matters.

[1] https://github.com/w3c/csswg-drafts/issues/9740

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/a44f91979c3a
https://hg.mozilla.org/integration/autoland/rev/ba63941d4041
Change behaviour of parent selector in @scope to be :where(:scope). r=firefox-style-system-reviewers,emilio
https://github.com/mozilla-firefox/firefox/commit/5dbaf0bb28a1
https://hg.mozilla.org/integration/autoland/rev/b7593b87da93
Adjust web-platform-tests for & being replaced by :where(:scope) in @scope. r=firefox-style-system-reviewers,emilio

Comment 5

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/53831 for changes under testing/web-platform/tests

Comment 6

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/ba63941d4041
https://hg.mozilla.org/mozilla-central/rev/b7593b87da93

Comment 7

[David Shin[:dshin]]

Attachment: Bug 1975531: Adjust WPT test as per upstream review. r=#style

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/97bf7293431c
https://hg.mozilla.org/integration/autoland/rev/3ab10e3da283
Adjust WPT test as per upstream review. r=firefox-style-system-reviewers,emilio

Comment 9

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/3ab10e3da283

Comment 10

[BugBot [:suhaib / :marco]]

A patch has been attached on this bug, which was already closed. Filing a separate bug will ensure better tracking. If this was not by mistake and further action is needed, please alert the appropriate party. (Or: if the patch doesn't change behavior -- e.g. landing a test case, or fixing a typo -- then feel free to disregard this message)

Comment 11

[David Shin[:dshin]]

(For future reference, this progressed WPT pull request here)

Comment 12

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by jgraham

Comment 13

[Brian Thomas Smith [:bsmth]]

MDN docs changes for this bug can be tracked here: https://github.com/mdn/content/issues/40481