[ZODB-Dev] strange testConnection error

[John Belmonte]

Several months ago my ZODB 3.3a3 application mysteriously stopped
working, perhaps triggered by some package upgrade (I track
Debian testing).  The error message (uncovered after much fighting
with the log system) was "CW: error in testConnection" from
ZEO/zrpc/client.py.  I traced the exception to a strange
"ImportError: No module named copy_reg" resulting from a
cPickle.Pickler() call.

I hoped that if I upgraded to ZODB 3.3.1a1, this problem might go
away.  It didn't.  I'm not usually one to post tracebacks, but I
don't know what to make of this:

Traceback (most recent call last):
   File "/usr/lib/python2.3/threading.py", line 442, in __bootstrap
   File "/usr/local/lib/python2.3/site-packages/ZEO/zrpc/client.py", line 293, in run
   File "/usr/local/lib/python2.3/site-packages/ZEO/zrpc/client.py", line 317, in try_connecting
   File "/usr/local/lib/python2.3/site-packages/ZEO/zrpc/client.py", line 345, in _create_wrappers
   File "/usr/local/lib/python2.3/site-packages/ZEO/zrpc/client.py", line 471, in connect_procedure
   File "/usr/local/lib/python2.3/site-packages/ZEO/zrpc/client.py", line 483, in test_connection
   File "/tmp/ZODB3-3.3.1a1/build/lib.linux-i686-2.3/ZEO/ClientStorage.py", line 466, in testConnection
   File "/tmp/ZODB3-3.3.1a1/build/lib.linux-i686-2.3/ZEO/ServerStub.py", line 85, in getAuthProtocol
   File "/tmp/ZODB3-3.3.1a1/build/lib.linux-i686-2.3/ZEO/zrpc/connection.py", line 370, in call
   File "/tmp/ZODB3-3.3.1a1/build/lib.linux-i686-2.3/ZEO/zrpc/connection.py", line 363, in send_call
   File "/tmp/ZODB3-3.3.1a1/build/lib.linux-i686-2.3/ZEO/zrpc/marshal.py", line 35, in encode
ImportError: No module named copy_reg

I only have Python 2.3.5 installed on my system, and it certainly
has a copy_reg module.  I'm also wondering why build paths are
showing up in the traceback-- the build directory doesn't even
exist any longer.

Any clues would be appreciated.

-John