2016-02-12 14:31 GMT+01:00 M.-A. Lemburg firstname.lastname@example.org:
If your program has bugs, you can use a debug build of Python 3.5 to detect misusage of the API.
Yes, but people don't necessarily do this, e.g. I have for a very long time ignored debug builds completely and when I started to try them, I found that some of the things I had been doing with e.g. free list implementations did not work in debug builds.
I just added support for debug hooks on Python memory allocators on Python compiled in *release* mode. Set the environment variable PYTHONMALLOC to debug to try with Python 3.6.
I added a check on PyObject_Malloc() debug hook to ensure that the function is called with the GIL held. I opened an issue to add a similar check on PyMem_Malloc(): https://bugs.python.org/issue26563
Yes, but those are part of the stdlib. You'd need to check a few C extensions which are not tested as part of the stdlib, e.g. numpy, scipy, lxml, pillow, etc. (esp. ones which implement custom types in C since these will often need the memory management APIs).
It may also be a good idea to check wrapper generators such as cython, swig, cffi, etc.
I ran the test suite of numpy, lxml, Pillow and cryptography (used cffi).
I found a bug in numpy. numpy calls PyMem_Malloc() without holding the GIL: https://github.com/numpy/numpy/pull/7404
Except of this bug, all other tests pass with PyMem_Malloc() using pymalloc and all debug checks.