1660804 - Bad rendering of pseudo-element with CSS custom property added through JS in an iframe

Status: RESOLVED FIXED

(Core :: DOM: CSS Object Model, defect)

Description

[dakur]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:80.0) Gecko/20100101 Firefox/80.0

Steps to reproduce:

I use TinyMCE editor and styled headings to have a little badge with heading level written down there after the heading text. This badge is implemented as and ::after pseudo-element and its content is passed through a custom property.

Actual results:

The badge does not render. When I open DOM Inspector and select the node in there (or whichever from editor's DOM) it appears.

See this codepen: https://codepen.io/dakur/pen/NWNdEQB

Expected results:

Render instantly.

Comment 1

[Andrei Purice]

Reproduced on the latest version of Firefox Nightly 82.0a1 (2020-08-27), beta 81.0b3 and release 80.0.

Setting a component for this issue in order to get the dev team involved.
If you feel it's an incorrect one please feel free to change it to a more appropriate one.

Comment 2

[Emilio Cobos Álvarez (:emilio)]

Attachment: Reduced test-case

For reference, attaching more minimal test-cases usually helps getting bugs looked at faster.

That being said this looks clearly broken, I'll poke. Thank you for filing!

Comment 3

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1660804 - Don't optimize ::before/::after away if content/display have been specified via custom properties. r=#style

We need to treat them the same way as we treat content: inherit.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/9863c168a18f
Don't optimize ::before/::after away if content/display have been specified via custom properties. r=jwatt

Comment 5

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

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/25646 for changes under testing/web-platform/tests

Comment 6

[Dorel Luca [:dluca]]

https://hg.mozilla.org/mozilla-central/rev/9863c168a18f

Comment 7

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

Upstream PR merged by moz-wptsync-bot

Comment 8

[dakur]

Great, thank you very much!

Comment 9

[BugBot [:suhaib / :marco/ :calixte]]

The patch landed in nightly and beta is affected.
:emilio, is this bug important enough to require an uplift?
If not please set status_beta to wontfix.

For more information, please visit auto_nag documentation.

Comment 10

[Emilio Cobos Álvarez (:emilio)]

Long-standing bug, can probably ride the trains.