I haven't been paying real close attention to the relative package import thread on python-dev, but some way or other I strongly believe something has to be done to improve the situation I now find myself in or more and more people are going to start getting bitten by the same sort of problem. Allow me to 'splain.
I use a web server based on Zope's ZServer (which is itself based on medusa) sitting behind an Apache web server as a long-running process to handle what many people traditionally used CGI for. It's a big performance boost over CGI. Unfortunately, I have recently been experiencing frequent server hangs. So far I've been unable to figure out what the cause is. I do notice occasional tracebacks like:
Unhandled exception in thread: Traceback (innermost last): File "ZServer/PubCore/ZServerPublisher.py", line 97, in __init__ File "/home/skip/src/Zope/ZServer/HTTPResponse.py", line 209, in _finish self.stdout.close() File "/home/skip/src/Zope/ZServer/HTTPResponse.py", line 235, in close self._channel.push(CallbackProducer(self._channel.done)) File "/home/skip/src/Zope/ZServer/HTTPServer.py", line 307, in push if send: self.initiate_send() File "/usr/lib/python1.5/asynchat.py", line 199, in initiate_send _push_mode = 0 File "/usr/lib/python1.5/asynchat.py", line 191, in refill_buffer self.ac_in_buffer = '' File "/usr/lib/python1.5/asynchat.py", line 253, in pop # this could maybe be made faster with a computed regex? IndexError: list index out of range
and also notice that the server can pile up a huge number of connections in the ESTABLISHED state, at which point the whole mess grinds to a halt with not much computation or network traffic happening. A separate shell script uses netstat to detect when a large number of sockets have piled up and restarts the server. Brutal, but crudely effective. (When in doubt, treat the symptoms...)
Today it just dawned on me looking at the above traceback that ZServer is getting the wrong version of asynchat.py (and presumably of asyncore.py as well). It's using the version delivered with Python 1.5.2 distribution instead of the version that was delivered with the version of Zope I'm using (1.something).
So I started looking around at the versions and dates of various copies of asynchat.py. Here's what I found:
source version number:date owner Python 1.5.2 1.2:1999/06/18 guido Python CVS 1.2:1999/06/18 guido Zope 1.? 1.7:1999/04/09 amos Zope 2.0 1.9:1999/07/19 amos Medusa 990902 2.24:1999/07/07 rushing
What's apparently been happening is that people have picked up asyncore and asynchat at various time and stuck them in their own CVS repositories without somehow freezing the Id string of the version they originally got from Sam Rushing. It's not clear what the differences are until you compare the actual files. It turns out that the Zope 2.0 and Medusa versions have no content differences, only wildly different version numbers. The Medusa and Python CVS versions only have one difference:
if index > 0: # don't bother reporting the empty string (source of subtle bugs) self.collect_incoming_data (self.ac_in_buffer[:index])
which *may* be what's causing my problems (note the IndexError in my traceback).
Somewhere along the way I think we need to apply more restraint to our packaging and numbering of Python modules. I don't know what form that restraint will eventually take, but at this point I'm willing to replace Greg Ward's s/must/should/ with s/should/must/.
a-nightmare-indeed!-i don't think-this-is-what-Sam-meant-ly y'rs