The PEP 3121 part is fixed by: commit d5cacbb1d9c3edc02bf0ba01702e7c06da5bc318 Author: Nick Coghlan <ncoghlan@gmail.com> Date: Sat May 23 22:24:10 2015 +1000 PEP 489: Multi-phase extension module initialization Known limitations of the current implementation: - documentation changes are incomplete - there's a reference leak I haven't tracked down yet The leak is most visible by running: ./python -m test -R3:3 test_importlib However, you can also see it by running: ./python -X showrefcount Importing the array or _testmultiphase modules, and then deleting them from both sys.modules and the local namespace shows significant increases in the total number of active references each cycle. By contrast, with _testcapi (which continues to use single-phase initialisation) the global refcounts stabilise after a couple of cycles.
