Issue #3437786 by quietone, longwave, catch, Gábor Hojtsy: Remove...

   */

  const CONNECTION_REFUSED = 2002;

  /**

   * Error code for "Can't initialize character set" error.

   */

  const UNSUPPORTED_CHARSET = 2019;

  /**

   * Driver-specific error code for "Unknown character set" error.

   */

  const UNKNOWN_CHARSET = 1115;

  /**

   * SQLSTATE error code for "Syntax error or access rule violation".

   */

  const SQLSTATE_SYNTAX_ERROR = 42000;

  /**

   * {@inheritdoc}

   */

   * {@inheritdoc}

   */

  public static function open(array &$connection_options = []) {

    if (isset($connection_options['_dsn_utf8_fallback']) && $connection_options['_dsn_utf8_fallback'] === TRUE) {

      // Only used during the installer version check, as a fallback from utf8mb4.

      $charset = 'utf8';

    }

    else {

      $charset = 'utf8mb4';

    }

    // The DSN should use either a socket or a host/port.

    if (isset($connection_options['unix_socket'])) {

      $dsn = 'mysql:unix_socket=' . $connection_options['unix_socket'];

    // Character set is added to dsn to ensure PDO uses the proper character

    // set when escaping. This has security implications. See

    // https://www.drupal.org/node/1201452 for further discussion.

    $dsn .= ';charset=' . $charset;

    $dsn .= ';charset=utf8mb4';

    if (!empty($connection_options['database'])) {

      $dsn .= ';dbname=' . $connection_options['database'];

    }

    // 'utf8mb4_general_ci' (MySQL 5) or 'utf8mb4_0900_ai_ci' (MySQL 8) for

    // utf8mb4.

    if (!empty($connection_options['collation'])) {

      $pdo->exec('SET NAMES ' . $charset . ' COLLATE ' . $connection_options['collation']);

      $pdo->exec('SET NAMES utf8mb4 COLLATE ' . $connection_options['collation']);

    }

    else {

      $pdo->exec('SET NAMES ' . $charset);

      $pdo->exec('SET NAMES utf8mb4');

    }

    // Set MySQL init_commands if not already defined.  Default Drupal's MySQL

use Drupal\mysql\Driver\Database\mysql\Connection;

use Drupal\Core\Database\DatabaseNotFoundException;

// cspell:ignore libmysqlclient

/**

 * Specifies installation tasks for MySQL and equivalent databases.

 */

   */

  const MARIADB_MINIMUM_VERSION = '10.3.7';

  /**

   * Minimum required MySQLnd version.

   */

  const MYSQLND_MINIMUM_VERSION = '5.0.9';

  /**

   * Minimum required libmysqlclient version.

   */

  const LIBMYSQLCLIENT_MINIMUM_VERSION = '5.5.3';

  /**

   * The PDO driver name for MySQL and equivalent databases.

   *

      // This doesn't actually test the connection.

      Database::setActiveConnection();

      // Now actually do a check.

      try {

      Database::getConnection();

      }

      catch (\Exception $e) {

        // Detect utf8mb4 incompatibility.

        if ($e->getCode() == Connection::UNSUPPORTED_CHARSET || ($e->getCode() == Connection::SQLSTATE_SYNTAX_ERROR && $e->errorInfo[1] == Connection::UNKNOWN_CHARSET)) {

          $this->fail(t('Your MySQL server and PHP MySQL driver must support utf8mb4 character encoding. Make sure to use a database system that supports this (such as MySQL/MariaDB/Percona 5.5.3 and up), and that the utf8mb4 character set is compiled in. See the <a href=":documentation" target="_blank">MySQL documentation</a> for more information.', [':documentation' => 'https://dev.mysql.com/doc/refman/5.0/en/cannot-initialize-character-set.html']));

          $info = Database::getConnectionInfo();

          $info_copy = $info;

          // Set a flag to fall back to utf8. Note: this flag should only be

          // used here and is for internal use only.

          $info_copy['default']['_dsn_utf8_fallback'] = TRUE;

          // In order to change the Database::$databaseInfo array, we need to

          // remove the active connection, then re-add it with the new info.

          Database::removeConnection('default');

          Database::addConnectionInfo('default', 'default', $info_copy['default']);

          // Connect with the new database info, using the utf8 character set so

          // that we can run the checkEngineVersion test.

          Database::getConnection();

          // Revert to the old settings.

          Database::removeConnection('default');

          Database::addConnectionInfo('default', 'default', $info['default']);

        }

        else {

          // Rethrow the exception.

          throw $e;

        }

      }

      $this->pass('Drupal can CONNECT to the database ok.');

    }

    catch (\Exception $e) {

    }

  }

  /**

   * {@inheritdoc}

   */

  protected function checkEngineVersion() {

    parent::checkEngineVersion();

    // Ensure that the MySQL driver supports utf8mb4 encoding.

    $version = Database::getConnection()->clientVersion();

    if (str_contains($version, 'mysqlnd')) {

      // The mysqlnd driver supports utf8mb4 starting at version 5.0.9.

      $version = preg_replace('/^\D+([\d.]+).*/', '$1', $version);

      if (version_compare($version, self::MYSQLND_MINIMUM_VERSION, '<')) {

        $this->fail(t("The MySQLnd driver version %version is less than the minimum required version. Upgrade to MySQLnd version %mysqlnd_minimum_version or up, or alternatively switch mysql drivers to libmysqlclient version %libmysqlclient_minimum_version or up.", ['%version' => $version, '%mysqlnd_minimum_version' => self::MYSQLND_MINIMUM_VERSION, '%libmysqlclient_minimum_version' => self::LIBMYSQLCLIENT_MINIMUM_VERSION]));

      }

    }

    else {

      // The libmysqlclient driver supports utf8mb4 starting at version 5.5.3.

      if (version_compare($version, self::LIBMYSQLCLIENT_MINIMUM_VERSION, '<')) {

        $this->fail(t("The libmysqlclient driver version %version is less than the minimum required version. Upgrade to libmysqlclient version %libmysqlclient_minimum_version or up, or alternatively switch mysql drivers to MySQLnd version %mysqlnd_minimum_version or up.", ['%version' => $version, '%libmysqlclient_minimum_version' => self::LIBMYSQLCLIENT_MINIMUM_VERSION, '%mysqlnd_minimum_version' => self::MYSQLND_MINIMUM_VERSION]));

      }

    }

  }

}