1774588 - Add relative selector parsing for :has(> a)

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, task)

Description

[Tiaan Louw [:tlouw]]

The :has selector only parses combinator selectors that has a type selector, e.g. p > a, but supports syntax like: :has(> a) which doesn't have the type selector.

Suggested fix is to fake the selector that is parsed to prepend the type of the :has element

Comment 1

[Sebastian Zartner [:sebo]]

(In reply to Tiaan Louw from comment #0)

Suggested fix is to fake the selector that is parsed to prepend the type of the :has element

Sorry for my ignorance as I have no idea how the parser actually works, but doesn't parsing relative selectors mean to start parsing expecting a combinator first?

Matching is a whole different beast, of course.
I'd expect it to work as if the selectors inside :has() wheren't surrounded by it. E.g. p:has(> a, > .class) + p would first match p > a and p > .class and remember the <p> elements matched by them. Then p + p is matched against the remembered ps.

And is this bug meant to cover both or only the parsing?

Sebastian

Comment 2

[Tiaan Louw [:tlouw]]

My apologies, I admit my comment is a bit light on details.

Sorry for my ignorance as I have no idea how the parser actually works, but doesn't parsing relative selectors mean to start parsing expecting a combinator first?

We don't handle relative selectors normally, because of marching, so we need to make :has an exception. Basically we plan to represent relative selector syntax by having a magic placeholder of sorts that represents the :has scope, but we don't serialize it. It follows a similar pattern used for the ::slotted selector.

And is this bug meant to cover both or only the parsing?

This would only be for the parsing part.

Comment 3

[D7460N]

Any progress on this? TIA

Comment 5

[David Shin[:dshin]]

Attachment: Bug 1774588 - Parsing for relative selectors in `:has()`. r=emilio,#layout-reviewers

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/3cf730621972
Parsing for relative selectors in `:has()`. r=emilio

Comment 7

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/3cf730621972