feat: add transaction-level advisory locks to sync_from_ui to prevent concurrent duplicate order processing

models/pos_order.py

@@ -100,3 +100,21 @@ class PosOrder(models.Model):
 
         return super(PosOrder, self)._process_order(order, existing_order)
 
+    @api.model
+    def sync_from_ui(self, orders):
+        """
+        Override to prevent concurrent processing of the same order uuid.
+        Uses pg_advisory_xact_lock on the order's uuid to force subsequent
+        duplicate requests to wait until the first request completes/commits.
+        """
+        # Sort orders by uuid to prevent potential deadlocks when locking multiple orders
+        sorted_orders = sorted(orders, key=lambda x: x.get('uuid') or '')
+        for order in sorted_orders:
+            uuid = order.get('uuid')
+            if uuid:
+                # Use PostgreSQL transaction-level advisory lock
+                self.env.cr.execute("SELECT pg_advisory_xact_lock(hashtext(%s))", (uuid,))
+
+        return super(PosOrder, self).sync_from_ui(orders)
+
+