diff --git a/composer.json b/composer.json
index 128af59..9746fd0 100644
--- a/composer.json
+++ b/composer.json
@@ -27,7 +27,8 @@
     "autoload": {
         "psr-4": {
             "Http\\Discovery\\": "src/"
-        }
+        },
+        "files": ["src/functions_include.php"]
     },
     "autoload-dev": {
         "psr-4": {
diff --git a/src/ClassDiscovery.php b/src/ClassDiscovery.php
index 760df6b..d17971c 100644
--- a/src/ClassDiscovery.php
+++ b/src/ClassDiscovery.php
@@ -161,7 +161,7 @@ protected static function evaluateCondition($condition)
     {
         if (is_string($condition)) {
             // Should be extended for functions, extensions???
-            return class_exists($condition);
+            return safe_class_exists($condition);
         } elseif (is_callable($condition)) {
             return $condition();
         } elseif (is_bool($condition)) {
diff --git a/src/Strategy/PuliBetaStrategy.php b/src/Strategy/PuliBetaStrategy.php
index 2666fb3..f87a7d0 100644
--- a/src/Strategy/PuliBetaStrategy.php
+++ b/src/Strategy/PuliBetaStrategy.php
@@ -3,6 +3,7 @@
 namespace Http\Discovery\Strategy;
 
 use Http\Discovery\Exception\PuliUnavailableException;
+use function Http\Discovery\safe_class_exists;
 use Puli\Discovery\Api\Discovery;
 use Puli\GeneratedPuliFactory;
 
@@ -41,7 +42,7 @@ private static function getPuliFactory()
 
             $puliFactoryClass = PULI_FACTORY_CLASS;
 
-            if (!class_exists($puliFactoryClass)) {
+            if (!safe_class_exists($puliFactoryClass)) {
                 throw new PuliUnavailableException('Puli Factory class does not exist');
             }
 
diff --git a/src/functions.php b/src/functions.php
new file mode 100644
index 0000000..1e23b87
--- /dev/null
+++ b/src/functions.php
@@ -0,0 +1,24 @@
+<?php
+
+namespace Http\Discovery;
+
+/**
+ * We want to do a "safe" version of PHP's "class_exists" because Magento has a bug
+ * (or they call it a "feature"). Magento is throwing an exception if you do class_exists()
+ * on a class that ends with "Factory" and if that file does not exits.
+ *
+ * This function will catch all potential exceptions and make sure it returns a boolean.
+ *
+ * @param string $class
+ * @param bool   $autoload
+ *
+ * @return bool
+ */
+function safe_class_exists($class, $autoload = true)
+{
+    try {
+        return class_exists($class, $autoload);
+    } catch (\Exception $e) {
+        return false;
+    }
+}
diff --git a/src/functions_include.php b/src/functions_include.php
new file mode 100644
index 0000000..8011b13
--- /dev/null
+++ b/src/functions_include.php
@@ -0,0 +1,6 @@
+<?php
+
+// Don't redefine the functions if included multiple times.
+if (!function_exists('Http\Discovery\safe_class_exists')) {
+    require __DIR__.'/functions.php';
+}