Fixing #251 support for circular references in lists

box/box_list.py

@@ -40,16 +40,16 @@ def __new__(cls, *args, **kwargs):
         # This is required for pickling to work correctly
         obj.box_options = {"box_class": box.Box}
         obj.box_options.update(kwargs)
-        obj.box_org_ref = 0
         return obj
 
     def __init__(self, iterable: Optional[Iterable] = None, box_class: Type[box.Box] = box.Box, **box_options):
         self.box_options = box_options
         self.box_options["box_class"] = box_class
-        self.box_org_ref = id(iterable) if iterable else 0
+        self.box_org_ref = iterable
         if iterable:
             for x in iterable:
                 self.append(x)
+        self.box_org_ref = None
         if box_options.get("frozen_box"):
 
             def frozen(*args, **kwargs):
@@ -101,7 +101,7 @@ def _convert(self, p_object):
         elif isinstance(p_object, box.Box):
             p_object._box_config.update(self.box_options)
         if isinstance(p_object, list) and not self._is_intact_type(p_object):
-            p_object = self.__class__(p_object, **self.box_options)
+            p_object = self if p_object is self or p_object is self.box_org_ref else self.__class__(p_object, **self.box_options)
         elif isinstance(p_object, BoxList):
             p_object.box_options.update(self.box_options)
         return p_object