I added a Misc/NEWS note for this in r65057.


This is a good candidate for backporting to release25-maint.


To answer Antoine Pitrou's question about using the old ident vs the new
_get_ident().  I don't know if the forked process will have the same
thread id.  I expect so.  If not, the code as recently committed will
die on an assertion failure because current_thread() is simply an
_active[_get_ident()] dict lookup that returns a DummyThread instance if
the lookup fails.


As for Windows, Windows doesn't support os.fork and I don't see any
calls to PyOS_AfterFork outside of the Modules/posixmodule.c.