This may be similar to #210641.  Example (Python 2.4.1,
Fedora Core 4 GNU/Linux):

sh-3.00$ python
Python 2.4.1 (#1, May 16 2005, 15:19:29)
[GCC 4.0.0 20050512 (Red Hat 4.0.0-5)] on linux2
Type "help", "copyright", "credits" or "license" for
more information.
>>> import signal
>>> signal.alarm(1)      # 1 second passes...
0
>>> Alarm clock
sh-3.00$   # python has exited

Doing the same thing in IDLE results in the subprocess
restarting.

IMO the correct behavior would be to raise an exception
that the outer shell would catch.