From c537c854c72e57c5561d9511d13ca993957c685c Mon Sep 17 00:00:00 2001
From: Philipp Cordes <pc@irgendware.net>
Date: Fri, 25 Jan 2019 00:11:57 +0100
Subject: [PATCH] Fix infinite recursion when passed an empty string

---
 .../Security/Core/Authorization/AccessDecisionManager.php      | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/Symfony/Component/Security/Core/Authorization/AccessDecisionManager.php b/src/Symfony/Component/Security/Core/Authorization/AccessDecisionManager.php
index 39cca72b7b9bc..5f5104f2a5b99 100644
--- a/src/Symfony/Component/Security/Core/Authorization/AccessDecisionManager.php
+++ b/src/Symfony/Component/Security/Core/Authorization/AccessDecisionManager.php
@@ -42,8 +42,9 @@ class AccessDecisionManager implements AccessDecisionManagerInterface
      */
     public function __construct($voters = [], $strategy = self::STRATEGY_AFFIRMATIVE, $allowIfAllAbstainDecisions = false, $allowIfEqualGrantedDeniedDecisions = true)
     {
+        $strategy = (string) $strategy;
         $strategyMethod = 'decide'.ucfirst($strategy);
-        if (!\is_callable([$this, $strategyMethod])) {
+        if (!\is_callable([$this, $strategyMethod]) || 0 === \strlen($strategy)) {
             throw new \InvalidArgumentException(sprintf('The strategy "%s" is not supported.', $strategy));
         }