Merge pull request #56 from iborysenko/patch-1

Default mapping operation must be cloned

src/Configuration/Mapping.php

@@ -353,7 +353,7 @@ public function withNameResolver(NameResolverInterface $nameResolver): MappingIn
     protected function getDefaultMappingOperation(): MappingOperationInterface
     {
         if ($this->defaultMappingOperation === null) {
-            $operation = $this->options->getDefaultMappingOperation();
+            $operation = clone $this->options->getDefaultMappingOperation();
             $operation->setOptions($this->options);
             $this->defaultMappingOperation = $operation;
         }