SF 952807: Unpickling pickled instances of subclasses of datetime.date,

datetime.datetime and datetime.time could yield insane objects.  Thanks
to Jiwon Seo for the fix.

Bugfix candidate.  I'll backport it to 2.3.

Lib/test/test_datetime.py

@@ -510,6 +510,9 @@ class TestDateOnly(unittest.TestCase):
         dt2 = dt - delta
         self.assertEqual(dt2, dt - days)
 
+class SubclassDate(date):
+    sub_var = 1
+
 class TestDate(HarmlessMixedComparison):
     # Tests here should pass for both dates and datetimes, except for a
     # few tests that TestDateTime overrides.
@@ -1029,6 +1032,15 @@ class TestDate(HarmlessMixedComparison):
         self.assertEqual(dt1.toordinal(), dt2.toordinal())
         self.assertEqual(dt2.newmeth(-7), dt1.year + dt1.month - 7)
 
+    def test_pickling_subclass_date(self):
+
+        args = 6, 7, 23
+        orig = SubclassDate(*args)
+        for pickler, unpickler, proto in pickle_choices:
+            green = pickler.dumps(orig, proto)
+            derived = unpickler.loads(green)
+            self.assertEqual(orig, derived)
+
     def test_backdoor_resistance(self):
         # For fast unpickling, the constructor accepts a pickle string.
         # This is a low-overhead backdoor.  A user can (by intent or
@@ -1053,6 +1065,9 @@ class TestDate(HarmlessMixedComparison):
 #############################################################################
 # datetime tests
 
+class SubclassDatetime(datetime):
+    sub_var = 1
+
 class TestDateTime(TestDate):
 
     theclass = datetime
@@ -1296,6 +1311,14 @@ class TestDateTime(TestDate):
         self.assertEqual(b.month, 2)
         self.assertEqual(b.day, 7)
 
+    def test_pickling_subclass_datetime(self):
+        args = 6, 7, 23, 20, 59, 1, 64**2
+        orig = SubclassDatetime(*args)
+        for pickler, unpickler, proto in pickle_choices:
+            green = pickler.dumps(orig, proto)
+            derived = unpickler.loads(green)
+            self.assertEqual(orig, derived)
+
     def test_more_compare(self):
         # The test_compare() inherited from TestDate covers the error cases.
         # We just want to test lexicographic ordering on the members datetime
@@ -1500,6 +1523,9 @@ class TestDateTime(TestDate):
         self.assertEqual(dt2.newmeth(-7), dt1.year + dt1.month +
                                           dt1.second - 7)
 
+class SubclassTime(time):
+    sub_var = 1
+
 class TestTime(HarmlessMixedComparison):
 
     theclass = time
@@ -1700,6 +1726,14 @@ class TestTime(HarmlessMixedComparison):
             derived = unpickler.loads(green)
             self.assertEqual(orig, derived)
 
+    def test_pickling_subclass_time(self):
+        args = 20, 59, 16, 64**2
+        orig = SubclassTime(*args)
+        for pickler, unpickler, proto in pickle_choices:
+            green = pickler.dumps(orig, proto)
+            derived = unpickler.loads(green)
+            self.assertEqual(orig, derived)
+
     def test_bool(self):
         cls = self.theclass
         self.failUnless(cls(1))

Misc/NEWS

@@ -12,6 +12,10 @@ What's New in Python 2.4 alpha 1?
 Core and builtins
 -----------------
 
+- Bug #952807:  Unpickling pickled instances of subclasses of
+  datetime.date, datetime.datetime and datetime.time could yield insane
+  objects.  Thanks to Jiwon Seo for a fix.
+
 - Bug #845802: Python crashes when __init__.py is a directory.
 
 - Unicode objects received two new methods: iswide() and width().

Modules/datetimemodule.c

@@ -2206,7 +2206,7 @@ date_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 	{
 	    	PyDateTime_Date *me;
 
-		me = PyObject_New(PyDateTime_Date, type);
+		me = (PyDateTime_Date *) (type->tp_alloc(type, 0));
 		if (me != NULL) {
 			char *pdata = PyString_AS_STRING(state);
 			memcpy(me->data, pdata, _PyDateTime_DATE_DATASIZE);
@@ -3049,8 +3049,7 @@ time_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 			}
 		}
 		aware = (char)(tzinfo != Py_None);
-		me = (PyDateTime_Time *) time_alloc(&PyDateTime_TimeType,
+		me = (PyDateTime_Time *) (type->tp_alloc(type, aware));
-						    aware);
 		if (me != NULL) {
 			char *pdata = PyString_AS_STRING(state);
 
@@ -3572,9 +3571,7 @@ datetime_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 			}
 		}
 		aware = (char)(tzinfo != Py_None);
-		me = (PyDateTime_DateTime *) datetime_alloc(
+		me = (PyDateTime_DateTime *) (type->tp_alloc(type , aware));
-						&PyDateTime_DateTimeType,
-				     		aware);
 		if (me != NULL) {
 			char *pdata = PyString_AS_STRING(state);