fix infinite loop

Author: nfourtythree

src/base/Purchasable.php

@@ -829,18 +829,23 @@ function($attribute, $params, Validator $validator) use ($lineItem, $lineItemQua
                         return;
                     }
 
+                    $lineItemPurchasable = $lineItem->getPurchasable();
+                    if (!$lineItemPurchasable instanceof Purchasable) {
+                        return;
+                    }
+
                     if (!$this->hasStock()) {
-                        if (!Plugin::getInstance()->getPurchasables()->isPurchasableOutOfStockPurchasingAllowed($lineItem->getPurchasable(), $lineItem->getOrder())) {
-                            $error = Craft::t('commerce', '“{description}” is currently out of stock.', ['description' => $lineItem->purchasable->getDescription()]);
+                        if (!Plugin::getInstance()->getPurchasables()->isPurchasableOutOfStockPurchasingAllowed($lineItemPurchasable, $lineItem->getOrder())) {
+                            $error = Craft::t('commerce', '“{description}” is currently out of stock.', ['description' => $lineItemPurchasable->getDescription()]);
                             $validator->addError($lineItem, $attribute, $error);
                         }
                     }
 
                     $lineItemQty = $lineItem->id !== null ? $lineItemQuantitiesById[$lineItem->id] : $lineItemQuantitiesByPurchasableId[$lineItem->purchasableId];
 
                     if ($this->hasStock() && $this->inventoryTracked && $lineItemQty > $this->getStock()) {
-                        if (!Plugin::getInstance()->getPurchasables()->isPurchasableOutOfStockPurchasingAllowed($lineItem->getPurchasable(), $lineItem->getOrder())) {
-                            $error = Craft::t('commerce', 'There are only {num} “{description}” items left in stock.', ['num' => $this->getStock(), 'description' => $lineItem->purchasable->getDescription()]);
+                        if (!Plugin::getInstance()->getPurchasables()->isPurchasableOutOfStockPurchasingAllowed($lineItemPurchasable, $lineItem->getOrder())) {
+                            $error = Craft::t('commerce', 'There are only {num} “{description}” items left in stock.', ['num' => $this->getStock(), 'description' => $lineItemPurchasable->getDescription()]);
                             $validator->addError($lineItem, $attribute, $error);
                         }
                     }

src/services/Purchasables.php

@@ -137,20 +137,20 @@ class Purchasables extends Component
 
 
     /**
-     * @param PurchasableInterface $purchasable
+     * @param Purchasable $purchasable
      * @param Order|null $order
      * @param User|null $currentUser
      * @return bool
      * @throws Throwable
      * @since 5.3.0
      */
-    public function isPurchasableOutOfStockPurchasingAllowed(PurchasableInterface $purchasable, Order $order = null, User $currentUser = null): bool
+    public function isPurchasableOutOfStockPurchasingAllowed(Purchasable $purchasable, Order $order = null, User $currentUser = null): bool
     {
         if ($currentUser === null) {
             $currentUser = Craft::$app->getUser()->getIdentity();
         }
 
-        $outOfStockPurchasesAllowed = $purchasable->getIsOutOfStockPurchasingAllowed();
+        $outOfStockPurchasesAllowed = $purchasable->allowOutOfStockPurchases;
 
         $event = new PurchasableOutOfStockPurchasesAllowedEvent(compact('order', 'purchasable', 'currentUser', 'outOfStockPurchasesAllowed'));