Merge branch '4.1'

* 4.1:
  [travis] fix composer.lock invalidation for deps=low
  [Security\Http] Restore laziness of listener iterator
  Make the `message_bus` alias public

Author: nicolas-grekas

DependencyInjection/FrameworkExtension.php

@@ -1507,7 +1507,7 @@ private function registerMessengerConfiguration(array $config, ContainerBuilder
             $container->register($busId, MessageBus::class)->addArgument(array())->addTag('messenger.bus');
 
             if ($busId === $config['default_bus']) {
-                $container->setAlias('message_bus', $busId);
+                $container->setAlias('message_bus', $busId)->setPublic(true);
                 $container->setAlias(MessageBusInterface::class, $busId);
             }
         }

Tests/DependencyInjection/FrameworkExtensionTest.php

@@ -530,6 +530,7 @@ public function testMessenger()
     {
         $container = $this->createContainerFromFile('messenger');
         $this->assertTrue($container->hasAlias('message_bus'));
+        $this->assertTrue($container->getAlias('message_bus')->isPublic());
         $this->assertFalse($container->hasDefinition('messenger.transport.amqp.factory'));
         $this->assertTrue($container->hasDefinition('messenger.transport_factory'));
         $this->assertSame(TransportFactory::class, $container->getDefinition('messenger.transport_factory')->getClass());