MC-38917: Unexpected order cancellation

Author: tsviklinskyi

app/code/Magento/Sales/Controller/Adminhtml/Order/Create/Index.php

@@ -23,7 +23,7 @@ public function execute()
 
         // Clear existing order in session when creating a new order for a customer
         if ($this->getRequest()->getParam('customer_id')) {
-            $this->clearSessionOrderData();
+            $this->_getSession()->setOrderId(null);
         }
 
         $this->_getOrderCreateModel()->initRuleData();
@@ -34,16 +34,4 @@ public function execute()
         $resultPage->getConfig()->getTitle()->prepend(__('New Order'));
         return $resultPage;
     }
-
-    /**
-     * Clear order data in session
-     *
-     * @return $this
-     */
-    private function clearSessionOrderData(): self
-    {
-        $this->_getSession()->setOrderId(null);
-
-        return $this;
-    }
 }

dev/tests/integration/testsuite/Magento/Sales/Controller/Adminhtml/Order/Create/IndexTest.php

@@ -52,9 +52,17 @@ protected function setUp(): void
     public function testExecute(): void
     {
         $customerId = 1;
+        $editingOrderId = 10;
+
         $this->getRequest()->setMethod(Http::METHOD_GET);
         $this->getRequest()->setParam('customer_id', $customerId);
+        $this->quoteSession->setOrderId($editingOrderId);
+        $this->assertEquals($editingOrderId, $this->quoteSession->getOrderId());
         $this->dispatch('backend/sales/order_create/index');
+
+        // Check that existing order in session was cleared
+        $this->assertEquals(null, $this->quoteSession->getOrderId());
+
         $store = $this->storeManager->getStore();
         $this->assertEquals($customerId, $this->quoteSession->getCustomerId());
         $ruleData = $this->registry->registry('rule_data');