From 75b21e9c869ce21dfa74b0fc1bb709b737127a45 Mon Sep 17 00:00:00 2001
From: Samuel ROZE <samuel.roze@gmail.com>
Date: Sun, 3 Dec 2017 13:07:37 +0000
Subject: [PATCH] Throw an exception is expression language is not installed

---
 .../Compiler/AnalyzeServiceReferencesPass.php                | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/Symfony/Component/DependencyInjection/Compiler/AnalyzeServiceReferencesPass.php b/src/Symfony/Component/DependencyInjection/Compiler/AnalyzeServiceReferencesPass.php
index 217c7c2034..a9b812e61d 100644
--- a/src/Symfony/Component/DependencyInjection/Compiler/AnalyzeServiceReferencesPass.php
+++ b/src/Symfony/Component/DependencyInjection/Compiler/AnalyzeServiceReferencesPass.php
@@ -14,6 +14,7 @@ namespace Symfony\Component\DependencyInjection\Compiler;
 use Symfony\Component\DependencyInjection\Argument\ArgumentInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\DependencyInjection\Definition;
+use Symfony\Component\DependencyInjection\Exception\RuntimeException;
 use Symfony\Component\DependencyInjection\ExpressionLanguage;
 use Symfony\Component\DependencyInjection\Reference;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
@@ -155,6 +156,10 @@ class AnalyzeServiceReferencesPass extends AbstractRecursivePass implements Repe
     private function getExpressionLanguage()
     {
         if (null === $this->expressionLanguage) {
+            if (!class_exists('Symfony\Component\ExpressionLanguage\ExpressionLanguage')) {
+                throw new RuntimeException('Unable to use expressions as the Symfony ExpressionLanguage component is not installed.');
+            }
+
             $providers = $this->container->getExpressionLanguageProviders();
             $this->expressionLanguage = new ExpressionLanguage(null, $providers, function ($arg) {
                 if ('""' === substr_replace($arg, '', 1, -1)) {