OXDEV-8721 Fix duplicate shipping costs calculation

Author: moritzdemmer

CHANGELOG-7.3.md

@@ -11,6 +11,7 @@
 ### Fixed
 - Shop ID resolution considers SSL language URLs
 - Email existence check when changing from user to guest email [#0006860](https://bugs.oxid-esales.com/view.php?id=6860)
+- Shipping costs calculation in cart and checkout after login [#0007682](https://bugs.oxid-esales.com/view.php?id=7682)
 
 ### Changed
 - Raised minimum required version of Symfony components to 6.4

source/Application/Model/Delivery.php

@@ -329,6 +329,10 @@ public function delete($sOxId = null)
      */
     public function isForBasket($oBasket)
     {
+        $this->_iItemCnt = 0;
+        $this->_iProdCnt = 0;
+        $this->_dPrice = 0;
+
         // amount for conditional check
         $blHasArticles = $this->hasArticles();
         $blHasCategories = $this->hasCategories();

tests/Integration/Legacy/Price/DeliveryCostTest.php

@@ -117,4 +117,30 @@ public function testGetDeliveryListWithRuleAssignedWillSkipWrongRule($testCase):
         $this->assertCount(1, $suitableDeliveries);
         $this->assertEquals('ok-rule', reset($suitableDeliveries)->getFieldData('oxtitle'));
     }
+
+    #[DataProvider('providerDeliveryCostRules')]
+    public function testDeliveryCostNotDoubledWithSameDeliveryObject(array $testCase): void
+    {
+        $basket = (new BasketConstruct())->calculateBasket($testCase);
+
+        $user = oxNew(User::class);
+        $user->load($testCase['user']['oxid']);
+        $deliveryList = oxNew(DeliveryList::class);
+        $deliveries = $deliveryList->getDeliveryList(
+            $basket,
+            $user,
+            BasketConstruct::getDefaultCountryId(),
+            $basket->getShippingId()
+        );
+        $delivery = reset($deliveries);
+
+        $delivery->isForBasket($basket);
+        $firstPrice = $delivery->getDeliveryPrice()->getBruttoPrice();
+
+        $delivery->setDeliveryPrice(null);
+        $delivery->isForBasket($basket);
+        $secondPrice = $delivery->getDeliveryPrice()->getBruttoPrice();
+
+        $this->assertEquals($firstPrice, $secondPrice);
+    }
 }