move mail event class

framework/CHANGELOG.md

@@ -132,6 +132,7 @@ Yii Framework 2 Change Log
 - Chg #3804: Added `fileinfo` PHP extension to the basic requirement of Yii (Ragazzo)
 - Chg #3866: The `FileValidator::types` property is renamed to `FileValidator::extensions` (Ragazzo)
 - Chg #3897: Raised visibility of `yii\web\View::registerAssetFiles()` to protected (samdark)
+- Chg #3899: Moved `MailEvent` class to `yii\mail` namespace (cebe)
 - Chg #3956: Flash messages set via `Yii::$app->session->setFlash()` will be removed only if they are accessed (qiangxue)
 - Chg: Replaced `clearAll()` and `clearAllAssignments()` in `yii\rbac\ManagerInterface` with `removeAll()`, `removeAllRoles()`, `removeAllPermissions()`, `removeAllRules()` and `removeAllAssignments()` (qiangxue)
 - Chg: Added `$user` as the first parameter of `yii\rbac\Rule::execute()` (qiangxue)

framework/UPGRADE.md

@@ -55,3 +55,5 @@ Upgrade from Yii 2.0 Beta
   This change is needed because `yii\web\View` no longer automatically generates CSRF meta tags due to issue #3358.
 
 * If your model code is using the `file` validation rule, you should rename its `types` option to `extensions`.
+
+* `MailEvent` class has been moved to the `yii\mail` namespace. You have to adjust all references that may exist in your code.

framework/base/MailEvent.php → framework/mail/MailEvent.php

@@ -5,10 +5,12 @@
  * @license http://www.yiiframework.com/license/
  */
 
-namespace yii\base;
+namespace yii\mail;
+
+use yii\base\Event;
 
 /**
- * ActionEvent represents the event parameter used for an action event.
+ * MailEvent represents the event parameter used for events triggered by [[BaseMailer]].
  *
  * By setting the [[isValid]] property, one may control whether to continue running the action.
  *
@@ -17,13 +19,12 @@ namespace yii\base;
  */
 class MailEvent extends Event
 {
-
     /**
-     * @var \yii\mail\MessageInterface mail message being send
+     * @var \yii\mail\MessageInterface the mail message being send.
      */
     public $message;
     /**
-     * @var boolean if message send was successful
+     * @var boolean if message was sent successfully.
      */
     public $isSuccessful;
     /**