1678945 - Color scheme simulation doesn't work on remote iframe when Fission is enabled

Status: RESOLVED FIXED

(DevTools :: Inspector, defect, P3)

Description

[Sebastian Zartner [:sebo]]

What were you doing?

1. Enable the preferences fission.autostart and devtools.inspector.color-scheme-simulation.enabled
2. Go to https://developer.mozilla.org/en-US/docs/Web/CSS/@media/prefers-color-scheme#Result
3. Open the Inspector
4. Toggle the color scheme simulation via the button in the Styles side panel

What happened?

When Fission is enabled, the color scheme simulation doesn't work.

What should have happened?

The <div>s in the example saying "changes in light/dark scheme" should change their background and foreground colors like they do when Fission is disabled.

Anything else we should know?

I've tested this using Nightly 85.0a1 (2020-11-22).

Sebastian

Comment 1

[Nicolas Chevobbe [:nchevobbe]]

DevTools code seems to run fine all the way to https://searchfox.org/mozilla-central/rev/f081504642a115cb8236bea4d8250e5cb0f39b02/devtools/server/actors/emulation/content-viewer.js#91 .

Emilio, would you know what's missing from emulatePrefersColorScheme (nsIContentViewer.idl) to make it work with Fission enabled?
Would that be fixed with Bug 1662840 or Bug 1591120 ?

Comment 2

[Emilio Cobos Álvarez (:emilio)]

I think those two bugs will fix this. The example is in a cross-origin iframe.

Comment 3

[Nicolas Chevobbe [:nchevobbe]]

thanks emilio!

Comment 4

[Nicolas Chevobbe [:nchevobbe]]

Bug 1679409 will have a test for a remote iframe (with fail-if = fission annotation)

Comment 5

[Neha Kochar [:neha]]

Honza said this is not part of dt-fission-m3-mvp and is not considered Fission M7 blocker.

Comment 6

[Chris Peterson [:cpeterson]]

Moving "dt-fission-m3-reserve" bugs to "dt-fission-future" because they don't block Fission MVP.

Comment 7

[Nicolas Chevobbe [:nchevobbe]]

The test highlighting the issue is now enabled on fission (https://hg.mozilla.org/mozilla-central/diff/11263420ea88cf234951aa2d015f30f8cd49c6a6/devtools/client/inspector/rules/test/browser_part1.ini), so we should be able to close this bug :)