I can confirm this is an issue for me as well.
Nov 10 2019
Jul 19 2019
Jun 21 2019
@matmarex Any progress on this?
Jan 22 2019
Closing this as I was able to verify the patch in T100896#4898625 manually (without vagrant).
taven@debug-wiki:/var/www/html/w$ php maintenance/validateRegistrationFile.php ~/mediawiki/Discord/skin.json /home/taven/mediawiki/Discord/skin.json did not pass validation. [OOUIThemePaths.Discord.styles] Array value found, but a string is required
Jan 19 2019
@matmarex I've been able successfuly test out your patch. However this breaks for RTL.
Jan 18 2019
Jan 15 2019
I see, I was under the assumption this was defined using the badgeicons.json file and being use by the theme via ResourceLoadeImageModule since it was defined in extension.json. My mistake. Closing this!
If you're developing one and the approach in my patch works for you, then perhaps that helps validate it and eases the minds of potential reviewers :)
Jan 14 2019
This may not be an issue isolated to oojs-ui (partly because it's not implemented). I can reproduce this in Echo as well when adding a defaultColor ResourceLoaderImageModule parameter in extension.json or in it's associated JSON file for images.
Jan 12 2019
Why isn't this merged? I've created a theme and I just realized that it didn't work because this wasn't merged. How is anyone supposed to create a MediaWiki theme if one organization(WikiMedia) is breaking it and hard coding for itself?