Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

vendor/symfony/console/Helper/HelperInterface.php

@@ -0,0 +1,49 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Console\Helper;
+
+/**
+ * HelperInterface is the interface all helpers must implement.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @api
+ */
+interface HelperInterface
+{
+    /**
+     * Sets the helper set associated with this helper.
+     *
+     * @param HelperSet $helperSet A HelperSet instance
+     *
+     * @api
+     */
+    public function setHelperSet(HelperSet $helperSet = null);
+
+    /**
+     * Gets the helper set associated with this helper.
+     *
+     * @return HelperSet A HelperSet instance
+     *
+     * @api
+     */
+    public function getHelperSet();
+
+    /**
+     * Returns the canonical name of this helper.
+     *
+     * @return string The canonical name
+     *
+     * @api
+     */
+    public function getName();
+}