force_return is a global loop parameter and default value is false

core/lib/Thelia/Core/HttpFoundation/Session/Session.php

@@ -164,10 +164,12 @@ class Session extends BaseSession
         $cart = null;
         if ($cart_id) {
             $cart = CartQuery::create()->findPk($cart_id);
-            try {
-                $this->verifyValidCart($cart);
-            } catch (InvalidCartException $e) {
-                $cart = null;
+            if($cart) {
+                try {
+                    $this->verifyValidCart($cart);
+                } catch (InvalidCartException $e) {
+                    $cart = null;
+                }
             }
         }
 

core/lib/Thelia/Core/Template/Element/BaseI18nLoop.php

@@ -73,7 +73,7 @@ abstract class BaseI18nLoop extends BaseLoop
             $columns,
             $foreignTable,
             $foreignKey,
-            $forceReturn
+            $this->getForce_return()
         );
     }
 }

core/lib/Thelia/Core/Template/Element/BaseLoop.php

@@ -89,6 +89,7 @@ abstract class BaseLoop
             Argument::createIntTypeArgument('page'),
             Argument::createIntTypeArgument('limit', PHP_INT_MAX),
             Argument::createBooleanTypeArgument('backend_context', false),
+            Argument::createBooleanTypeArgument('force_return', false),
         );
     }