By claudiu.cristea on
Change record status: 
Published (View all published change records)
Project: 
Drupal core
Introduced in branch: 
8.8.x
Introduced in version: 
8.8.0
Issue links: 
https://www.drupal.org/node/3035274
Description: 

Procedural functions drupal_classloader_register() and system_register() are deprecated. Use the class_loader service to add new namespaces.

Before

drupal_classloader_register('some_module', 'modules/custom/some_module');

system_register('module', 'some_module', 'modules/some_module/some_module.info.yml');

After

// Instead of drupal_classloader_register.
\Drupal::service('class_loader')->classLoader->addPsr4('Drupal\\some_module\\',  \Drupal::root() . '/modules/custom/some_module/src');

// Instead of system_register()
$path = \Drupal::service('extension.list.module')->getPath('some_module');
\Drupal::service('class_loader')->classLoader->addPsr4('Drupal\\some_module\\',  \Drupal::root() . $path . '/src');
Impacts: 
Module developers
Themers
Site templates, recipes and distribution developers