Issue #2939904 by alexpott, Mile23: Fix system_get_info() for non-installed modules

    /** @var \Drupal\Core\Extension\ModuleExtensionList $module_list */

    $module_list = \Drupal::service('extension.list.module');

    if (isset($name)) {

      try {

        return $module_list->getExtensionInfo($name);

      }

      catch (\InvalidArgumentException $e) {

        return [];

      }

    }

    else {

      return $module_list->getAllInstalledInfo();

    }

<?php

namespace Drupal\Tests\system\Kernel\System;

use Drupal\KernelTests\KernelTestBase;

/**

 * Tests system_get_info().

 *

 * @group system

 */

class SystemGetInfoTest extends KernelTestBase {

  public static $modules = ['system'];

  /**

   * Tests system_get_info().

   */

  public function testSystemGetInfo() {

    $system_module_info = system_get_info('module', 'system');

    $this->assertSame('System', $system_module_info['name']);

    $this->assertSame(['system' => $system_module_info], system_get_info('module'));

    // The User module is not installed so system_get_info() should return

    // an empty array.

    $this->assertSame([], system_get_info('module', 'user'));

    // Install the User module and check system_get_info() returns the correct

    // information.

    $this->container->get('module_installer')->install(['user']);

    $user_module_info = system_get_info('module', 'user');

    $this->assertSame('User', $user_module_info['name']);

    $this->assertSame(['system' => $system_module_info, 'user' => $user_module_info], system_get_info('module'));

    // Test theme info. There are no themes installed yet.

    $this->assertSame([], system_get_info('theme', 'stable'));

    $this->assertSame([], system_get_info('theme'));

    $this->container->get('theme_installer')->install(['stable']);

    $stable_theme_info = system_get_info('theme', 'stable');

    $this->assertSame('Stable', $stable_theme_info['name']);

    $this->assertSame(['stable' => $stable_theme_info], system_get_info('theme'));

  }

}