Memory leak free OrderedDict alternative in Python 2.7?

Question

We are checking whether one of our packages leaves garbage objects in the Python gc and found that collections.OrderedDict objects are not deleted by the ref-count mechanism but are put into the GC, with the following references (when pprint'ing them and tweaking the output a little):

<type 'list'> object at 0x10a876ab8:
[ <Recursive reference to list object at 0x10a876ab8>,
  <Recursive reference to list object at 0x10a876ab8>,
  None]

This seems to be the same issue as the one reported in https://bugs.python.org/issue9825. That issue was fixed in Python 3.2, and indeed, the reference cycle shown above appears on Python 2.7 but not on Python 3.7.

Is there a ref-cycle free alternative to collections.OrderedDict for Python 2.7?

Update:

1. I found that ordereddict.OrderedDict also has the same reference cycle.

2. I am fully aware that Python 2.7 is out of support. Nevertheless, we still need to support our package on Python 2.7.

3. The answer of @Ramsha Siddiqui points to the SortedDict of Django. I verified that in Django 1.7, its SortedDict does not have reference cycles. However, SortedDict was removed from Django (at least in its version 1.11).

Answer 1

You can use sorted() on any dictionary's items like so:

odt = dict(sorted(dt.items()))

UPDATE: Preserving Original Order

If you want to preserve original order, there is a Django libary for that too:

from django.utils.datastructures import SortedDict
d2 = SortedDict()

Let me know if this helps your case.

UPDATE: [Duplicate] Reference: Python ordered garbage collectible dictionary?

del collections.OrderedDict.__del__

This seems to be the solution for gaining the ability to use OrderedDicts in a reference cycle. You will lose having the OrderedDict free all its resources immediately upon deletion.