From 3502020834a401416c2c5d35e6ac6026d39fae72 Mon Sep 17 00:00:00 2001
From: Ryan Weaver <ryan@thatsquality.com>
Date: Thu, 23 Nov 2017 14:17:09 -0500
Subject: [PATCH] adding checks for the expression language

---
 .../Component/DependencyInjection/Loader/XmlFileLoader.php    | 4 ++++
 .../Component/DependencyInjection/Loader/YamlFileLoader.php   | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php b/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php
index d839ab267d318..598cf36f859a6 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php
@@ -506,6 +506,10 @@ private function getArgumentsAsPhp(\DOMElement $node, $name, $file, $lowercase =
                     $arguments[$key] = new Reference($arg->getAttribute('id'), $invalidBehavior);
                     break;
                 case 'expression':
+                    if (!class_exists(Expression::class)) {
+                        throw new \LogicException(sprintf('The type="expression" attribute cannot be used without the ExpressionLanguage component. Try running "composer require symfony/expression-language".'));
+                    }
+
                     $arguments[$key] = new Expression($arg->nodeValue);
                     break;
                 case 'collection':
diff --git a/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php b/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
index 3af504d9e7959..81d3ccb881558 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
@@ -775,6 +775,10 @@ private function resolveServices($value, $file, $isParameter = false)
                 $value[$k] = $this->resolveServices($v, $file, $isParameter);
             }
         } elseif (is_string($value) && 0 === strpos($value, '@=')) {
+            if (!class_exists(Expression::class)) {
+                throw new \LogicException(sprintf('The "@=" expression syntax cannot be used without the ExpressionLanguage component. Try running "composer require symfony/expression-language".'));
+            }
+
             return new Expression(substr($value, 2));
         } elseif (is_string($value) && 0 === strpos($value, '@')) {
             if (0 === strpos($value, '@@')) {