Issue #3490843 by nicxvan, smustgrave, oily, joachim, berdir, alexpott,...

use Drupal\Component\Utility\UrlHelper;

use Drupal\Core\Database\Database;

use Drupal\Core\Extension\Dependency;

use Drupal\Core\Extension\Extension;

use Drupal\Core\Extension\ExtensionDiscovery;

use Drupal\Core\Extension\InstallRequirementsInterface;

use Drupal\Core\Installer\InstallerKernel;

use Symfony\Component\HttpFoundation\RedirectResponse;

      if (function_exists($function)) {

        $requirements = array_merge($requirements, $function('install'));

      }

      $requirements = array_merge($requirements, install_check_class_requirements($module_list[$module]));

    }

  }

    $requirements = array_merge($requirements, $function('install'));

  }

  $extension = \Drupal::service('extension.list.profile')->get($profile);

  $requirements = array_merge($requirements, install_check_class_requirements($extension));

  return $requirements;

}

function drupal_check_module($module) {

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

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

  $file = DRUPAL_ROOT . '/' . $module_list->getPath($module) . "/$module.install";

  $extension = $module_list->get($module);

  $file = \Drupal::root() . '/' . $extension->getPath() . "/$module.install";

  if (is_file($file)) {

    require_once $file;

  }

  // Check requirements

  $requirements = \Drupal::moduleHandler()->invoke($module, 'requirements', ['install']);

  if (is_array($requirements) && drupal_requirements_severity($requirements) == REQUIREMENT_ERROR) {

  $requirements = \Drupal::moduleHandler()->invoke($module, 'requirements', ['install']) ?? [];

  $requirements = array_merge($requirements, install_check_class_requirements($extension));

  if (!empty($requirements) && drupal_requirements_severity($requirements) == REQUIREMENT_ERROR) {

    // Print any error messages

    foreach ($requirements as $requirement) {

      if (isset($requirement['severity']) && $requirement['severity'] == REQUIREMENT_ERROR) {

  }

  return $cache[$profile][$langcode];

}

/**

 * Checks a module or profile requirements.

 *

 * See \Drupal\Core\Extension\InstallRequirementsInterface for more information.

 *

 * @param \Drupal\Core\Extension $extension

 *   The extension to check install requirements for.

 *

 * @return array

 *   The requirements.

 *

 * @internal

 */

function install_check_class_requirements(Extension $extension): array {

  $extension_path = $extension->getPath();

  $extension_name = $extension->getName();

  $dir = \Drupal::root() . "/$extension_path/src/Install/Requirements";

  $requirements = [];

  if (is_dir($dir)) {

    $fileSystemIterator = new FilesystemIterator($dir);

    foreach ($fileSystemIterator as $fileInfo) {

      if ($fileInfo->isFile() && $fileInfo->getExtension() === 'php') {

        $filename = $fileInfo->getFilename();

        $requirements_path = $dir . '/' . $filename;

        require_once $requirements_path;

        $namespace = "Drupal\\$extension_name\\Install\\Requirements";

        $class_name = $namespace . '\\' . $fileInfo->getBasename('.php');

        if (class_exists($class_name) && class_implements($class_name, InstallRequirementsInterface::class)) {

          $requirements = $class_name::getRequirements();

        }

      }

    }

  }

  return $requirements;

}

<?php

namespace Drupal\Core\Extension;

/**

 * Provides method for checking requirements during install time.

 */

interface InstallRequirementsInterface {

  /**

   * Check installation requirements.

   *

   * Classes implementing this must be in the Install/Requirements namespace.

   * For example src/Install/Requirements/ModuleNameRequirements.php.

   *

   * During the 'install' phase, modules can for example assert that

   * library or server versions are available or sufficient.

   * Note that the installation of a module can happen during installation of

   * Drupal itself (by install.php) with an installation profile or later by hand.

   * As a consequence, install-time requirements must be checked without access

   * to the full Drupal API, because it is not available during install.php.

   * If a requirement has a severity of REQUIREMENT_ERROR, install.php will abort

   * or at least the module will not install.

   * Other severity levels have no effect on the installation.

   * Module dependencies do not belong to these installation requirements,

   * but should be defined in the module's .info.yml file.

   *

   * During installation, if you need to load a class from your module,

   * you'll need to include the class file directly.

   *

   * @return array

   *   An associative array where the keys are arbitrary but must be unique (it

   *   is suggested to use the module short name as a prefix) and the values are

   *   themselves associative arrays with the following elements:

   *   - title: The name of the requirement.

   *   - value: This should only be used for version numbers, do not set it if

   *     not applicable.

   *   - description: The description of the requirement/status.

   *   - severity: (optional) The requirement's result/severity level, one of:

   *     - REQUIREMENT_INFO: For info only.

   *     - REQUIREMENT_OK: The requirement is satisfied.

   *     - REQUIREMENT_WARNING: The requirement failed with a warning.

   *     - REQUIREMENT_ERROR: The requirement failed with an error.

   *     Defaults to REQUIREMENT_OK when installing.

   */

  public static function getRequirements(): array;

}

name: 'Test Install Requirements Class'

type: module

description: 'Support module for testing install requirements.'

package: Testing

version: VERSION

<?php

declare(strict_types=1);

namespace Drupal\module_install_requirements\Install\Requirements;

use Drupal\Core\Extension\InstallRequirementsInterface;

/**

 * Provides method for checking requirements during install time.

 */

class ModuleInstallRequirements implements InstallRequirementsInterface {

  /**

   * {@inheritdoc}

   */

  public static function getRequirements(): array {

    $GLOBALS['module_install_requirements'] = 'module_install_requirements';

    return [];

  }

}

name: 'Test Install Requirements Class'

type: module

description: 'Support module for testing install unmet requirements.'

package: Testing

version: VERSION