After updating to Drupal 8.4 I now have an error in my browser when trying to load my Drupal site:
Error: Class '\Drupal\rest\PathProcessor\PathProcessorEntityResourceBC' not found in Drupal\Component\DependencyInjection\Container->createService() (line 262 of core/lib/Drupal/Component/DependencyInjection/Container.php)
If I execute a drush or drupal console command the error is the same but with more of a stacktrace.
I upgraded to Drush 9 which simplifies the error a bit more:
Service 'rest.path_processor_entity_resource_bc' for consumer 'path_processor_manager' does not implement Drupal\Core\PathProcessor\InboundPathProcessorInterface.
It looks like I have some dependency missing somewhere. I'm not sure how to track it down.
I have tried "composer install", "composer update", and removing the vendor directory and re-installing the composer packages but nothing has worked yet.
Has anyone had this error or know how to get the missing PathProcessorEntityResourceBC class?
drush up
will break things. In that case, I would revert to a backup and then update core through composer.