pickle: maximum recursion depth exceeded

[Simon Burton]

Here is a simple example that breaks pickle.
(With N=256 all is well.)
This probably should go in the docs for pickle -
that highly interlinked data cannot be pickled.
I know that in the past we have been told not to
do this, because of GC issues, so I understand
if it's considered too pathalogical for now.

Simon.

#!/usr/bin/env python

#import cPickle as pickle
import pickle
import os
#sys.setrecursionlimit(4000)

N = 512
print "building..."
nest = [ [] for i in range(N) ]
for i in range(N):
  for j in range(N):
    nest[i].append( nest[j] )

print "dumping..."
file = open("nest.pkl","wb")
try:
  pickle.dump( nest, file )
except RuntimeError, e:
  print e