1569292 - `+` CSS selector in combination with :empty in shadow DOM only refreshes when opening inspector

Status: NEW

(Core :: CSS Parsing and Computation, defect, P3)

Description

[Tim Nguyen :ntim]

Testcase: https://nt1m.github.io/playground/shadow-dom-bug/

STR:

• Click the button

Expected result:

• "foo" and "bar" should be shown

Actual result:

• only "foo" is shown

If you open devtools, then you get the expected result

Comment 1

[Tim Nguyen :ntim]

mozregression brought me at bug 1410578, but I'm looking if I can reproduce using <style> instead of <link rel="stylesheet"> so I can provide a more useful regression range.

Comment 2

[Tim Nguyen :ntim]

I'm otherwise getting https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=d3910b7628b8066d3f30d58b17b5824b05768854&tochange=515407ebfa1433c31144374313bbfd8b942af41

but before the regression range, I get this.attachShadow is undefined so I guess it's not that useful either.

Comment 3

[Emilio Cobos Álvarez (:emilio)]

FWIW, opening devtools just causes .bar to be restyled because devtools inject stylesheets in the page.

Comment 4

[Emilio Cobos Álvarez (:emilio)]

So the issue is that we hit the early return here, because the grand parent (the ShadowRoot) doesn't have the flags.

This is because of this code, which looks at parent_element and maybe should look at parent node.

Wrapping .foo and .bar under another element works around the issue. This is pretty similar to bug 1480746. I want to fix all these in bug 1480477, though maybe I can fix them earlier / separately.

Comment 5

[Emilio Cobos Álvarez (:emilio)]

So the issue here is specific to :empty, as far as I can tell.