Fix the BC layer for the switch to multiple delivery addresses

Author: stof

DependencyInjection/Configuration.php

@@ -11,6 +11,7 @@
 
 namespace Symfony\Bundle\SwiftmailerBundle\DependencyInjection;
 
+use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
 use Symfony\Component\Config\Definition\Builder\TreeBuilder;
 use Symfony\Component\Config\Definition\ConfigurationInterface;
 
@@ -88,6 +89,22 @@ private function getMailersNode()
             ->requiresAtLeastOneElement()
             ->useAttributeAsKey('name')
                 ->prototype('array')
+            // BC layer for "delivery_address: null" (the case of a string goes through the XML normalization too)
+            ->beforeNormalization()
+                ->ifTrue(function ($v) {
+                    return array_key_exists('delivery_address', $v) && null === $v['delivery_address'];
+                })
+                ->then(function ($v) {
+                    @trigger_error('The swiftmailer.delivery_address configuration key is deprecated since version 2.3.10 and will be removed in 3.0. Use the swiftmailer.delivery_addresses configuration key instead (or remove the empty setting)', E_USER_DEPRECATED);
+                    unset($v['delivery_address']);
+
+                    if (!isset($v['delivery_addresses'])) {
+                        $v['delivery_addresses'] = array();
+                    }
+
+                    return $v;
+                })
+            ->end()
             ->children()
                 ->scalarNode('url')->defaultNull()->end()
                 ->scalarNode('transport')->defaultValue('smtp')->end()
@@ -113,6 +130,7 @@ private function getMailersNode()
                 ->end()
                 ->scalarNode('sender_address')->end()
                 ->arrayNode('delivery_addresses')
+                    ->performNoDeepMerging()
                     ->beforeNormalization()
                         ->ifArray()
                         ->then(function ($v) { return array_values($v); })