SwiftMailer message updated to setup charset for alternative body correctly.

extensions/yii/swiftmailer/Message.php

@@ -188,6 +188,7 @@ class Message extends BaseMessage
 	{
 		$message = $this->getSwiftMessage();
 		$oldBody = $message->getBody();
+		$charset = $message->getCharset();
 		if (empty($oldBody)) {
 			$parts = $message->getChildren();
 			$partFound = false;
@@ -195,6 +196,7 @@ class Message extends BaseMessage
 				if (!($part instanceof \Swift_Mime_Attachment)) {
 					/* @var \Swift_Mime_MimePart $part */
 					if ($part->getContentType() == $contentType) {
+						$charset = $part->getCharset();
 						unset($parts[$key]);
 						$partFound = true;
 						break;
@@ -204,7 +206,7 @@ class Message extends BaseMessage
 			if ($partFound) {
 				reset($parts);
 				$message->setChildren($parts);
-				$message->addPart($body, $contentType);
+				$message->addPart($body, $contentType, $charset);
 			} else {
 				$message->setBody($body, $contentType);
 			}
@@ -215,8 +217,8 @@ class Message extends BaseMessage
 			} else {
 				$message->setBody(null);
 				$message->setContentType(null);
-				$message->addPart($oldBody, $oldContentType);
+				$message->addPart($oldBody, $oldContentType, $charset);
-				$message->addPart($body, $contentType);
+				$message->addPart($body, $contentType, $charset);
 			}
 		}
 	}

tests/unit/extensions/swiftmailer/MessageTest.php

@@ -341,4 +341,23 @@ class MessageTest extends VendorTestCase
 		$unserializedMessaage = unserialize($serializedMessage);
 		$this->assertEquals($message, $unserializedMessaage, 'Unable to unserialize message!');
 	}
+
+	/**
+	 * @depends testSendAlternativeBody
+	 */
+	public function testAlternativeBodyCharset()
+	{
+		$message = $this->createTestMessage();
+		$charset = 'windows-1251';
+		$message->setCharset($charset);
+
+		$message->setTextBody('some text');
+		$message->setHtmlBody('some html');
+		$content = $message->toString();
+		$this->assertEquals(2, substr_count($content, $charset), 'Wrong charset for alternative body.');
+
+		$message->setTextBody('some text override');
+		$content = $message->toString();
+		$this->assertEquals(2, substr_count($content, $charset), 'Wrong charset for alternative body override.');
+	}
 }