because (essentially) I didn't realise that PY_BEGIN/END_ALLOW_THREADS
actually expanded to nothing under a no-threads build, so if you somehow
NULLed out the threadstate (e.g. by calling PyThread_SaveThread) it would
stay NULLed when you return to Python. Argh!
Backport candidate.
[ 1166660 ] The readline module can cause python to segfault
It seems to me that the code I'm rewriting here attempted to call any
user-supplied hook functions using the thread state of the thread that
called the hook-setting function, as opposed to that of the thread
that is currently executing. This doesn't work, in general.
Fix this by using the PyGILState API (It wouldn't be that hard to
define a dummy version of said API when #ifndef WITH_THREAD, would
it?).
Also, check the conversion to integer of the return value of a hook
function for errors (this problem was mentioned in the ipython bug
report linked to in the above bug).
[ 960406 ] unblock signals in threads
although the changes do not correspond exactly to any patch attached to
that report.
Non-main threads no longer have all signals masked.
A different interface to readline is used.
The handling of signals inside calls to PyOS_Readline is now rather
different.
These changes are all a bit scary! Review and cross-platform testing
much appreciated.
