From acbde502bf4d3548ae9a1a8a9a3b6d47b668850d Mon Sep 17 00:00:00 2001
From: Karoly Negyesi <chx1975@gmail.com>
Date: Sat, 25 Oct 2014 06:19:21 -0700
Subject: [PATCH] Break infinite loop while resolving aliases

---
 .../Compiler/ResolveReferencesToAliasesPass.php       |  6 ++++++
 .../Compiler/ResolveReferencesToAliasesPassTest.php   | 11 +++++++++++
 2 files changed, 17 insertions(+)

diff --git a/src/Symfony/Component/DependencyInjection/Compiler/ResolveReferencesToAliasesPass.php b/src/Symfony/Component/DependencyInjection/Compiler/ResolveReferencesToAliasesPass.php
index 015bdebc8b..c90d76f48a 100644
--- a/src/Symfony/Component/DependencyInjection/Compiler/ResolveReferencesToAliasesPass.php
+++ b/src/Symfony/Component/DependencyInjection/Compiler/ResolveReferencesToAliasesPass.php
@@ -12,6 +12,7 @@
 namespace Symfony\Component\DependencyInjection\Compiler;
 
 use Symfony\Component\DependencyInjection\Alias;
+use Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException;
 use Symfony\Component\DependencyInjection\Reference;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 
@@ -84,7 +85,12 @@ class ResolveReferencesToAliasesPass implements CompilerPassInterface
      */
     private function getDefinitionId($id)
     {
+        $seen = array();
         while ($this->container->hasAlias($id)) {
+            if (isset($seen[$id])) {
+                throw new ServiceCircularReferenceException($id, array_keys($seen));
+            }
+            $seen[$id] = true;
             $id = (string) $this->container->getAlias($id);
         }
 
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Compiler/ResolveReferencesToAliasesPassTest.php b/src/Symfony/Component/DependencyInjection/Tests/Compiler/ResolveReferencesToAliasesPassTest.php
index ca089a556b..6fdc233941 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Compiler/ResolveReferencesToAliasesPassTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Compiler/ResolveReferencesToAliasesPassTest.php
@@ -48,6 +48,17 @@ class ResolveReferencesToAliasesPassTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals('foo', (string) $arguments[0]);
     }
 
+    /**
+     * @expectedException \Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException
+     */
+    public function testAliasCircularReference()
+    {
+        $container = new ContainerBuilder();
+        $container->setAlias('bar', 'foo');
+        $container->setAlias('foo', 'bar');
+        $this->process($container);
+    }
+
     protected function process(ContainerBuilder $container)
     {
         $pass = new ResolveReferencesToAliasesPass();