Add the same _keep_alive patch (by Michael Scharff) that was added to
copy.deepcopy() a while ago. Can't reproduce this but it doesn't
break anything and it looks like the code could have the same problem.
diff --git a/Lib/pickle.py b/Lib/pickle.py
index bc01c90..97eb4e4 100644
--- a/Lib/pickle.py
+++ b/Lib/pickle.py
@@ -473,6 +473,7 @@
if hasattr(object, '__getinitargs__'):
args = object.__getinitargs__()
len(args) # XXX Assert it's a sequence
+ _keep_alive(args, memo)
else:
args = ()
@@ -501,6 +502,7 @@
stuff = object.__dict__
else:
stuff = getstate()
+ _keep_alive(stuff, memo)
save(stuff)
write(BUILD)
dispatch[InstanceType] = save_inst
@@ -523,6 +525,23 @@
dispatch[BuiltinFunctionType] = save_global
+def _keep_alive(x, memo):
+ """Keeps a reference to the object x in the memo.
+
+ Because we remember objects by their id, we have
+ to assure that possibly temporary objects are kept
+ alive by referencing them.
+ We store a reference at the id of the memo, which should
+ normally not be used unless someone tries to deepcopy
+ the memo itself...
+ """
+ try:
+ memo[id(memo)].append(x)
+ except KeyError:
+ # aha, this is the first one :-)
+ memo[id(memo)]=[x]
+
+
classmap = {}
def whichmodule(cls, clsname):