1809505 - Style containment not working well with counters on pseudo-elements

Status: NEW

(Core :: Layout: Generated Content, Lists, and Counters, defect)

Description

[Oriol Brufau [:Oriol]]

Attachment: style-containment.html

Load attached testcase.

Expected:

[::before=0]
  1. [::before=1][::after=1]
  [::before=0]    <-- Here
    1. [::before=1][::after=1]
  [::after=1]
  2. [::before=2][::after=2]
[::after=2]

Actual:

[::before=0]
  1. [::before=1][::after=1]
  [::before=1]    <-- Here
    1. [::before=1][::after=1]
  [::after=1]
  2. [::before=2][::after=2]
[::after=2]

Also, layout is not stable. if then I run

var div = document.querySelector("div");
div.style.display = "none";
div.offsetLeft;
div.style.display = "";

it becomes

[::before=0]
  1. [::before=1][::after=1]
  [::before=2]    <-- Here
    1. [::before=1][::after=1]
  [::after=1]
  2. [::before=2][::after=2]
[::after=2]

Comment 1

[Oriol Brufau [:Oriol]]

Attachment: style-containment.html

I forgot about https://drafts.csswg.org/css-contain/#containment-style

the counter() and counters() value of the content property is not itself scoped, and can refer to counters established outside of the subtree.

So the initial result is actually good. I'm attaching a better testcase with counters().

[::before=0]
  1. [::before=1][::after=1]
  [::before=1]
    1. [::before=1.1][::after=1.1]
  [::after=1.1]
  2. [::before=2][::after=2]
[::after=2]

But when I run the JS, it wrongly becomes

[::before=0]
  1. [::before=1][::after=1]
  [::before=2]
    1. [::before=2.1][::after=2.1]
  [::after=2.1]
  2. [::before=2][::after=2]
[::after=2]

Comment 2

[Tiaan Louw]

Reproduced on nightly 110

Comment 3

[Emilio Cobos Álvarez (:emilio)]

Martin, do you have cycles to take a look at this? No big deal if not but it seems it might not be too hard to address.

Comment 4

[Martin Robinson (email:[e-mail])]

Sure. I can take a look at this failure.

Comment 5

[Martin Robinson (email:[e-mail])]

Please accept my apologies for dropping the ball on this issue. I think that I may not have time to tackle it in the short term. :(