By catch on
Change record status: 
Published (View all published change records)
Project: 
Drupal core
Introduced in branch: 
11.2.x
Introduced in version: 
11.2.0
Issue links: 
https://www.drupal.org/node/3502882
Description: 

A new API and associated classloader has been added to enable renaming classes in the code base.

This allows classes to be renamed or moved to different namespaces, without having to leave the old class in the code base, only the services.yml entries are required.

module.services.yml now supports a moved_classes parameter. This specifies the old and new class, with optional deprecation suppport.

Without deprecation:

parameters:
  core.moved_classes:
    'Drupal\Core\StringTranslation\TranslationWrapper':
      class: 'Drupal\Core\StringTranslation\TranslatableMarkup'

With deprecation:

parameters:
  module_autoload_test.moved_classes:
    'Drupal\module_autoload_test\Foo':
      class: 'Drupal\module_autoload_test\Bar'
      deprecation_version: drupal:11.2.0
      removed_version: drupal:12.0.0
      change_record: https://www.drupal.org/project/drupal/issues/3502882

When the old class is autoloaded, the classloader will detect this, and swap it for the new one using class_alias(). When the deprecation-related keys are specified, the classloader will trigger E_USER_DEPRECATED with a message.

The non-deprecation version should only be used where there is a specific reason to leave the alias permanently, for example if the class is used in serialized data which cannot be easily updated.

Impacts: 
Module developers