From 91a70fcd6fb5bce09d4622cbaecf2467c24fef69 Mon Sep 17 00:00:00 2001
From: Samuel ROZE <samuel.roze@gmail.com>
Date: Thu, 25 Oct 2018 11:45:27 +0200
Subject: [PATCH] If `framework.messenger.buses.X.middleware` is empty, it will
 be `null`

---
 .../FrameworkBundle/DependencyInjection/Configuration.php       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
index c594d24c6468a..00500644c41a5 100644
--- a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
+++ b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
@@ -1090,7 +1090,7 @@ function ($a) {
                                     ->end()
                                     ->arrayNode('middleware')
                                         ->beforeNormalization()
-                                            ->ifTrue(function ($v) { return \is_string($v) || !\is_int(key($v)); })
+                                            ->ifTrue(function ($v) { return \is_string($v) || (\is_array($v) && !\is_int(key($v))); })
                                             ->then(function ($v) { return array($v); })
                                         ->end()
                                         ->defaultValue(array())