By scott_euser on
Change record status: 
Draft (View all draft change records)
Project: 
Drupal core
Introduced in branch: 
11.x
Introduced in version: 
11.4.0
Issue links: 
https://www.drupal.org/node/2642122
Description: 

If a parent theme overrode a grandparent theme, the theme libraries overrides would no longer work the same and a non-obvious workaround was needed. Now a library override of a grandparent theme is done in the same way as the first override.

For example, Olivero's olivero.info.yml has:

libraries-override:
  core/drupal.ajax:
    css:
      component:
        core/components/ajax-progress.module.css: css/components/ajax-progress.module.css

If a sub-theme of Olivero is created, let's call it Verona can now do this in verona.info.yml:

libraries-override:
  core/drupal.ajax:
    css:
      component:
        core/components/ajax-progress.module.css: false

Previously developers would need to search where the css was overridden and hard-code the path like:

libraries-override:
  core/drupal.ajax:
    css:
      component:
        /core/themes/olivero/css/components/ajax-progress.module.css: false
Impacts: 
Themers