From: Guido van Rossum <guido@python.org>
Date: Wed, 20 May 1998 22:25:32 +0000 (+0000)
Subject: Trivial little change: when setting a member to an object, hold the
X-Git-Tag: v1.5.2a1~575
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=adf0e437cb15791c9bbfd99929388f3ff8e07e3a;p=thirdparty%2FPython%2Fcpython.git

Trivial little change: when setting a member to an object, hold the
old value in a temporary and XDECREF it only after then new value has
been set.  This prevents the (unlikely) case where the destructor of
the member uses the containing object -- it would find it in an
undefined state.
---

diff --git a/Python/structmember.c b/Python/structmember.c
index 02464c611f0a..ba0772008ab3 100644
--- a/Python/structmember.c
+++ b/Python/structmember.c
@@ -167,6 +167,7 @@ PyMember_Set(addr, mlist, name, v)
 	PyObject *v;
 {
 	struct memberlist *l;
+	PyObject *oldv;
 	
 	for (l = mlist; l->name != NULL; l++) {
 		if (strcmp(l->name, name) == 0) {
@@ -253,9 +254,10 @@ PyMember_Set(addr, mlist, name, v)
 				}
 				break;
 			case T_OBJECT:
-				Py_XDECREF(*(PyObject **)addr);
 				Py_XINCREF(v);
+				oldv = *(PyObject **)addr;
 				*(PyObject **)addr = v;
+				Py_XDECREF(oldv);
 				break;
 			case T_CHAR:
 				if (PyString_Check(v) &&