Why do I get an error about the extension.list.module service non existing?

Question

I installed Drupal 8.5.6 and Drupal Commerce with Composer. They installed fine, but after I cleared the cache, I got this exception in a WSOD.

Uncaught PHP Exception Symfony\Component\DependencyInjection\Exception\ServiceNotFoundException: "You have requested a non-existent service "extension.list.module"." at C:\wamp\www\drupal-8.5.6\core\lib\Drupal\Component\DependencyInjection\Container.php line 151

I searched for extension.list.module and I found this.

function system_rebuild_module_data() {
  return \Drupal::service('extension.list.module')->reset()->getList();
}

What did I do wrong to cause this problem?
What is my next step to solve this dilemma?

Answer 1

When Drupal loads some 'foo.bar' service (e.g. \Drupal::service('extension.list.module')), it expects this service to be defined in one of the somemodule/somemodule.services.yml files. For example:

services:
  extension.list.module:
    class: Drupal\somewhere\SomeService

This particular service (extension.list.module) is defined in core/core.services.yml

  extension.list.module:
    class: Drupal\Core\Extension\ModuleExtensionList

This should be available by default, so either the Drupal core files are missing or your lost some integrity of your data in your database. Try rebuilding cache (e.g. drush cache:rebuild), if it fails, manually clear all cache_* tables (especially cache_bootstrap). Otherwise restore your database from the backup.