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

vendor/symfony/console/Question/ConfirmationQuestion.php

@@ -0,0 +1,61 @@
+<?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\Question;
+
+/**
+ * Represents a yes/no question.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class ConfirmationQuestion extends Question
+{
+    private $trueAnswerRegex;
+
+    /**
+     * Constructor.
+     *
+     * @param string $question        The question to ask to the user
+     * @param bool   $default         The default answer to return, true or false
+     * @param string $trueAnswerRegex A regex to match the "yes" answer
+     */
+    public function __construct($question, $default = true, $trueAnswerRegex = '/^y/i')
+    {
+        parent::__construct($question, (bool) $default);
+
+        $this->trueAnswerRegex = $trueAnswerRegex;
+        $this->setNormalizer($this->getDefaultNormalizer());
+    }
+
+    /**
+     * Returns the default answer normalizer.
+     *
+     * @return callable
+     */
+    private function getDefaultNormalizer()
+    {
+        $default = $this->getDefault();
+        $regex = $this->trueAnswerRegex;
+
+        return function ($answer) use ($default, $regex) {
+            if (is_bool($answer)) {
+                return $answer;
+            }
+
+            $answerIsTrue = (bool) preg_match($regex, $answer);
+            if (false === $default) {
+                return $answer && $answerIsTrue;
+            }
+
+            return !$answer || $answerIsTrue;
+        };
+    }
+}