ModuleExtensionList::getName() is not compatible with ModuleHandler::getName()

Problem/Motivation

At #2926070: Deprecate ModuleHandlerInterface::getName() it is going to replace \Drupal\Core\Extension\ModuleHandlerInterface::getName() with: \Drupal::service('extension.list.module')->getName($module) the problem is that ModuleHandler::getName() returns the name machine name of the module if it does not found the module name. There is even a docblock mentioning it:

/**
   * Gets the human readable name of a given module.
   *
   * @param string $module
   *   The machine name of the module which title should be shown.
   *
   * @return string
   *   Returns the human readable name of the module or the machine name passed
   *   in if no matching module is found.
   */
  public function getName($module);

And \Drupal::service('extension.list.module')->getName($module) triggers an exception if the module does not exists.

So, starting on Drupal 8.6 this is causing a WSOD whenever a non-existent module is passed to ModuleHander::getName()

Proposed resolution

The posible solutions:

• Rewrite the docblock reflecting this change at ModuleHandler::getName() and write a change record
• Make \Drupal::service('extension.list.module')->getName($module) returns the machine name if the module does not exists.
• Catch the \Drupal::service('extension.list.module')->getName($module) exception and return the expected value at ModuleHandlerInterface::getName()

Remaining tasks

User interface changes

API changes

Data model changes