From 34fa80b8a8cb9bd7c96696828f2b78bd8839c391 Mon Sep 17 00:00:00 2001
From: Fran Moreno <franmomu@gmail.com>
Date: Sun, 16 Dec 2018 17:05:02 +0100
Subject: [PATCH] Fix deprecation for symfony/config 4.2+

---
 src/CoreBundle/DependencyInjection/Configuration.php | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/CoreBundle/DependencyInjection/Configuration.php b/src/CoreBundle/DependencyInjection/Configuration.php
index 99aa761e..5f51c8a8 100644
--- a/src/CoreBundle/DependencyInjection/Configuration.php
+++ b/src/CoreBundle/DependencyInjection/Configuration.php
@@ -25,8 +25,14 @@ class Configuration implements ConfigurationInterface
 {
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('sonata_core');
+        $treeBuilder = new TreeBuilder('sonata_core');
+
+        // Keep compatibility with symfony/config < 4.2
+        if (!\method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->root('sonata_core');
+        } else {
+            $rootNode = $treeBuilder->getRootNode();
+        }
 
         $this->addFlashMessageSection($rootNode);
         $this->addSerializerFormats($rootNode);