fix sf4 deprecated: cannotBeEmpty() is not allowed with arrayNode

DependencyInjection/Configuration.php

@@ -85,7 +85,7 @@ class Configuration implements ConfigurationInterface
                                             ->scalarNode('key')
                                                 ->isRequired()->cannotBeEmpty()
                                             ->end()
-                                            ->arrayNode('labels')->isRequired()->cannotBeEmpty()
+                                            ->arrayNode('labels')->requiresAtLeastOneElement()
                                                 ->children()
                                                     ->scalarNode('lang')->isRequired()->cannotBeEmpty()
                                                         ->example('fr')

Widget/PersonListWidgetFactory.php

@@ -44,7 +44,7 @@ class PersonListWidgetFactory extends AbstractWidgetFactory
                 ->info("Add some custom field to the view. Add the slug of some custom field"
                         . " if you want to override the view and show their value in the list")
                 ->example(array("custom-field-slug-1", "custom-field-slug-2"))
-                ->cannotBeEmpty()
+                ->requiresAtLeastOneElement()
                 ->end();
     }