From: Guido van Rossum <guido@python.org>
Date: Wed, 20 Aug 1997 22:26:19 +0000 (+0000)
Subject: Make sure the objects returned by __getinitargs__() are kept alive (in
X-Git-Tag: v1.5a4~356
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=558be283bf2c3a2c405c8a404da1cfed69900226;p=python

Make sure the objects returned by __getinitargs__() are kept alive (in
the memo) to avoid a certain kind of nasty crash.  (Not easily
reproducable because it requires a later call to __getinitargs__() to
return a tuple that happens to be allocated at the same address.)
---

diff --git a/Lib/copy.py b/Lib/copy.py
index 6dc781c4e0..ef5b10edd0 100644
--- a/Lib/copy.py
+++ b/Lib/copy.py
@@ -195,11 +195,28 @@ def _deepcopy_dict(x, memo):
 	return y
 d[types.DictionaryType] = _deepcopy_dict
 
+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]
+
 def _deepcopy_inst(x, memo):
 	if hasattr(x, '__deepcopy__'):
 		return x.__deepcopy__()
 	if hasattr(x, '__getinitargs__'):
 		args = x.__getinitargs__()
+		_keep_alive(args, memo)
 		args = deepcopy(args, memo)
 	else:
 		args = ()
@@ -207,6 +224,7 @@ def _deepcopy_inst(x, memo):
 	memo[id(x)] = y
 	if hasattr(x, '__getstate__'):
 			state = x.__getstate__()
+			_keep_alive(state, memo)
 	else:
 			state = x.__dict__
 	state = deepcopy(state, memo)