Issue #3195197: Use a factory service to create Mailchimp library

mailchimp.module

@@ -9,7 +9,6 @@ use Drupal\Component\Utility\Crypt;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Render\Markup;
 use Drupal\Core\Site\Settings;
-use Drupal\mailchimp\Autoload;
 use Mailchimp\MailchimpLists;
 
 define('MAILCHIMP_QUEUE_CRON', 'mailchimp');
@@ -22,6 +21,9 @@ define('MAILCHIMP_STATUS_SENDING', 'sending');
 
 /**
  * Access callback for mailchimp submodule menu items.
+ *
+ * @return bool
+ *   TRUE if the mailchimp api is available and accessible by the user.
  */
 function mailchimp_apikey_ready_access($permission) {
   if (mailchimp_get_api_object() && \Drupal::currentUser()->hasPermission($permission)) {
@@ -33,49 +35,18 @@ function mailchimp_apikey_ready_access($permission) {
 /**
  * Instantiates a Mailchimp library object.
  *
- * @return \Mailchimp
+ * @return \Mailchimp\Mailchimp
  *   Drupal Mailchimp library object.
  */
 function mailchimp_get_api_object($classname = 'Mailchimp') {
-  $mailchimp = &drupal_static(__FUNCTION__);
-  if (isset($mailchimp) && $mailchimp instanceof $classname) {
-    return $mailchimp;
-  }
-
-  $config = \Drupal::config('mailchimp.settings');
+  $object = \Drupal::service('mailchimp.client_factory')->getByClassNameOrNull($classname);
 
-  if ($config->get('test_mode')) {
-    // Register autoloader for loading test classes.
-    Autoload::register();
-    $classname = '\Mailchimp\Tests\\' . $classname;
-  }
-  else {
-    $classname = '\Mailchimp\\' . $classname;
-  }
-
-  if (!class_exists($classname)) {
-    $msg = t('Failed to load Mailchimp PHP library. Please refer to the installation requirements.');
-    \Drupal::logger('mailchimp')->error($msg);
-    \Drupal::messenger()->addError($msg);
-    return NULL;
-  }
-
-  $api_key = $config->get('api_key');
-  if (!strlen($api_key)) {
-    \Drupal::logger('mailchimp')->error('Mailchimp Error: API Key cannot be blank.');
+  if (!$object) {
+    \Drupal::messenger()->addError('Failed to load Mailchimp PHP library. Please refer to the installation requirements.');
     return NULL;
   }
 
-  $http_options = [
-    'timeout' => $config->get('api_timeout'),
-    'headers' => [
-      'User-Agent' => _mailchimp_get_user_agent(),
-    ],
-  ];
-
-  $mailchimp = new $classname($api_key, 'apikey', $http_options);
-
-  return $mailchimp;
+  return $object;
 }
 
 /**