1117572 - Implement >>> Selecting Through Shadows Selector for access into shadow root

Status: RESOLVED WONTFIX

(Core :: CSS Parsing and Computation, enhancement)

Description

[Rodney Rehm]

The "selecting through shadows selector" (also referred to "shadow-piercing descendant combinator") allows selecting elements within regardless of them being in a ShadowRoot or nested ShadowRoot or not. It is somewhat similar to ::shadow [1].

Note: The ">>>" selector used to be called "/deep/" (and is currently implemented in Chrome as "/deep/".

Link to specification for reference: http://dev.w3.org/csswg/css-scoping-1/#deep-combinator

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1112251

Comment 1

[Anne (:annevk)]

We should not implement this until there's agreement that this is actually desired. See https://github.com/w3c/webcomponents/issues/78.

Comment 2

[Thomas Wisniewski]

It seems that Chrome 60 will be treating the >>> combinator as the descendant combinator, so perhaps it would be wise to simply follow suit?

https://developers.google.com/web/updates/2017/06/chrome-60-deprecations#make_shadow-piercing_descendant_combinator_behave_like_descendent_combinator

Comment 3

[Anne (:annevk)]

Thomas, as per comment 1 I don't think we should implement this. There's no agreement on this feature.

Comment 4

[Thomas Wisniewski]

I agree, but we may wish to wait and see if we need to support it as a descendant combinator as Chrome does per comment 2 (for the sake of webcompat).

Comment 5

[Olli Pettay [:smaug][[e-mail]]]

Based on the current state of the spec issues -> WONTFIX.