The mysql.views.cast_sql service depends on the views module and exists when views is not installed

Maybe we could improve \Drupal\Core\DependencyInjection\Compiler\BackendCompilerPass instead, and remove the backend-specific service from the container if the main service doesn't exist.

@amateescu but without views installed we have no idea that mysql.views.cast_sql exists to override views.cast_sql

@alexpott, but we do know that mysql.views.cast_sql is a backend override service because it's tagged with backend_overridable, and then we just need to split the backend name from its ID to find out the main service ID.

I'm not sure that MR was meant for this issue though :)

alexpott → changed the visibility of the branch 3493595-the-mysql.views.castsql-service to hidden.

@amateescu we only know that it is an override once the views service exists. This is about sites without views installed. The MySQL service is not tagged.

Fixed the MR.

Ohh.. that's right, somehow I didn't realize that only the main service is tagged :)

The kernel test failure seems to be caused by this change.

The kernel failure occurred because before we had two services in services.yml files implementing \Drupal\views\Plugin\views\query\CastSqlInterface and now we have 1 - ie. the one in views.services.yml so now it errors. The best fix is to add the missing alias. The fact this is in a plugin directory is odd because it is a backend overridable service and it only ever accessed in real runtime code by doing \Drupal::service('views.cast_sql') so it's not a plugin at all. Anyhow that's not something this issue needs to resolve.