1576229 - Dynamic changes due to rules in user sheets don't get applied in Shadow DOM

Status: RESOLVED FIXED

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

Description

[Dalton]

Attachment: Add-on demonstrating CSS application to Shadow DOM contents

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.42 Safari/537.36

Steps to reproduce:

Using the add-on attached to this issue, I'm attempting to style Shadow DOM contents with CSS inserted by the add-on (with a cssOrigin of user). The styles are applied on initial load as expected, but aren't being applied when the Shadow DOM content changes.

STR:

1. Load the attached add-on into Firefox.
2. Navigate to any web page. A red box should appear in the top left corner.
3. Click the "Toggle blue background" button.

Actual results:

The box's background color doesn't change even though its class changes to "blue" and CSS to change the background color has been inserted by the add-on.

Expected results:

The box's background color should have changed from red to blue as defined by the "blue" class being toggled and the associated CSS inserted by the add-on.

I have tested the attached add-on in Chrome and Opera and the background changes to blue as expected when clicking the "Toggle blue background" button.

Comment 1

[Henri Sivonen (:hsivonen)]

What does the spec require?

Comment 2

[Anne (:annevk)]

I haven't looked at the add-on, but if we don't take dynamic changes into account that seems like a bug. Per the specification add-ons are kinda out-of-scope.

Comment 3

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1576229 - Account for user stylesheets for Shadow DOM invalidation.

Comment 4

[Emilio Cobos Álvarez (:emilio)]

So this is because it's a user stylesheet... It's not 100% clear to me how Shadow DOM and user sheets interact, but right now we're handling it inconsistently.

I've attached an automated test that reproduces the issue, though I haven't investigated the root cause of the bug yet.

Comment 5

[Emilio Cobos Álvarez (:emilio)]

(Didn't mean to cancel ni?)

Comment 6

[Emilio Cobos Álvarez (:emilio)]

Ok, back now, the bug was so silly that it's embarrassing, whoops :)

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/19e21bdb79cb
Account for user stylesheets for Shadow DOM invalidation. r=jwatt

Comment 8

[Alexandru Michis [:malexandru]]

https://hg.mozilla.org/mozilla-central/rev/19e21bdb79cb

Comment 9

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/releases/mozilla-beta/rev/19e21bdb79cb