Crash using DictionaryServices on 10.12

Attached is a simple project that shows the problem. To reproduce:

$ python setup.py build_ext
$ python 
>>> import dummy
>>> dummy.func()

This works fine.

$ python3 setup.py build_ext
$ python3
>>> import dummy
>>> dummy.func()

This crashes the interpreter from a secondary thread. The only difference between the two is the Python version: the working command sequence is using /usr/bin/python on OSX 10.12, the other is using Python 3.5.2 (python.org installer) on the same machine.

This extension doesn't use PyObjC at all, and shows that there is some difference between the Python.org binary and /usr/bin/python that causes problems.

The same crash occurs using python.org's python 2.7.12 installer.

And a local build of 3.5 (unix build, no shared libs, no framework) works fine.

Next step is build my own full framework installation using the 10.12 SDK.

I'll investigate this later, this is not a PyObjC issue and shouldn't delay the next PyObjC release.

This is still a problem.

Removing version: 3.0 (automated comment)

Two tests crash hard on 10.12 and 10.13 (see #174), disable tests on those platform

As issue #174 mentions these crashes are due to something in the CPython installer,
not PyObjC itself.

→ <<cset 0e6fdd242f35>>