[Mailer] Fixed generator bug when creating multiple transports using Transport::fromDsn

src/Symfony/Component/Mailer/Tests/TransportTest.php

@@ -60,6 +60,22 @@ class TransportTest extends TestCase
         ];
     }
 
+    /**
+     * @dataProvider fromDsnProvider
+     */
+    public function testFromDsn(string $dsn, TransportInterface $transport): void
+    {
+        $this->assertEquals($transport, Transport::fromDsn($dsn));
+    }
+
+    public function fromDsnProvider(): iterable
+    {
+        yield 'multiple transports' => [
+            'failover(smtp://a smtp://b)',
+            new FailoverTransport([new Transport\Smtp\EsmtpTransport('a'), new Transport\Smtp\EsmtpTransport('b')]),
+        ];
+    }
+
     /**
      * @dataProvider fromWrongStringProvider
      */

src/Symfony/Component/Mailer/Transport.php

@@ -51,7 +51,7 @@ class Transport
 
     public static function fromDsn(string $dsn, EventDispatcherInterface $dispatcher = null, HttpClientInterface $client = null, LoggerInterface $logger = null): TransportInterface
     {
-        $factory = new self(self::getDefaultFactories($dispatcher, $client, $logger));
+        $factory = new self(iterator_to_array(self::getDefaultFactories($dispatcher, $client, $logger)));
 
         return $factory->fromString($dsn);
     }