Fix marshal's incorrect handling of subclasses of builtin types (backport candidate).
diff --git a/Doc/library/marshal.rst b/Doc/library/marshal.rst
index 19a56d7..4f5b16a 100644
--- a/Doc/library/marshal.rst
+++ b/Doc/library/marshal.rst
@@ -45,12 +45,6 @@
(they will cause infinite loops).
.. warning::
-
- Some unsupported types such as subclasses of builtins will appear to marshal
- and unmarshal correctly, but in fact, their type will change and the
- additional subclass functionality and instance attributes will be lost.
-
-.. warning::
On machines where C's ``long int`` type has more than 32 bits (such as the
DEC Alpha), it is possible to create plain Python integers that are longer
diff --git a/Lib/test/test_marshal.py b/Lib/test/test_marshal.py
index 656fc1f..1b2c8b7 100644
--- a/Lib/test/test_marshal.py
+++ b/Lib/test/test_marshal.py
@@ -244,6 +244,17 @@
last.append([0])
self.assertRaises(ValueError, marshal.dumps, head)
+ def test_exact_type_match(self):
+ # Former bug:
+ # >>> class Int(int): pass
+ # >>> type(loads(dumps(Int())))
+ # <type 'int'>
+ for typ in (int, long, float, complex, tuple, list, dict, set, frozenset):
+ # Note: str and unicode sublclasses are not tested because they get handled
+ # by marshal's routines for objects supporting the buffer API.
+ subtyp = type('subtyp', (typ,), {})
+ self.assertRaises(ValueError, marshal.dumps, subtyp())
+
def test_main():
test_support.run_unittest(IntTestCase,
FloatTestCase,
diff --git a/Misc/NEWS b/Misc/NEWS
index 502b182..997a49a 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -812,6 +812,10 @@
Extension Modules
-----------------
+- Marshal.dumps() now expects exact type matches for int, long, float, complex,
+ tuple, list, dict, set, and frozenset. Formerly, it would silently miscode
+ subclasses of those types. Now, it raises a ValueError instead.
+
- Patch #1388440: Add set_completion_display_matches_hook and
get_completion_type to readline.
diff --git a/Python/marshal.c b/Python/marshal.c
index 897c15e..0c611b6 100644
--- a/Python/marshal.c
+++ b/Python/marshal.c
@@ -144,7 +144,7 @@
else if (v == Py_True) {
w_byte(TYPE_TRUE, p);
}
- else if (PyInt_Check(v)) {
+ else if (PyInt_CheckExact(v)) {
long x = PyInt_AS_LONG((PyIntObject *)v);
#if SIZEOF_LONG > 4
long y = Py_ARITHMETIC_RIGHT_SHIFT(long, x, 31);
@@ -159,7 +159,7 @@
w_long(x, p);
}
}
- else if (PyLong_Check(v)) {
+ else if (PyLong_CheckExact(v)) {
PyLongObject *ob = (PyLongObject *)v;
w_byte(TYPE_LONG, p);
n = ob->ob_size;
@@ -169,7 +169,7 @@
for (i = 0; i < n; i++)
w_short(ob->ob_digit[i], p);
}
- else if (PyFloat_Check(v)) {
+ else if (PyFloat_CheckExact(v)) {
if (p->version > 1) {
unsigned char buf[8];
if (_PyFloat_Pack8(PyFloat_AsDouble(v),
@@ -190,7 +190,7 @@
}
}
#ifndef WITHOUT_COMPLEX
- else if (PyComplex_Check(v)) {
+ else if (PyComplex_CheckExact(v)) {
if (p->version > 1) {
unsigned char buf[8];
if (_PyFloat_Pack8(PyComplex_RealAsDouble(v),
@@ -236,7 +236,7 @@
}
}
#endif
- else if (PyString_Check(v)) {
+ else if (PyString_CheckExact(v)) {
if (p->strings && PyString_CHECK_INTERNED(v)) {
PyObject *o = PyDict_GetItem(p->strings, v);
if (o) {
@@ -273,7 +273,7 @@
w_string(PyString_AS_STRING(v), (int)n, p);
}
#ifdef Py_USING_UNICODE
- else if (PyUnicode_Check(v)) {
+ else if (PyUnicode_CheckExact(v)) {
PyObject *utf8;
utf8 = PyUnicode_AsUTF8String(v);
if (utf8 == NULL) {
@@ -293,7 +293,7 @@
Py_DECREF(utf8);
}
#endif
- else if (PyTuple_Check(v)) {
+ else if (PyTuple_CheckExact(v)) {
w_byte(TYPE_TUPLE, p);
n = PyTuple_Size(v);
w_long((long)n, p);
@@ -301,7 +301,7 @@
w_object(PyTuple_GET_ITEM(v, i), p);
}
}
- else if (PyList_Check(v)) {
+ else if (PyList_CheckExact(v)) {
w_byte(TYPE_LIST, p);
n = PyList_GET_SIZE(v);
w_long((long)n, p);
@@ -309,7 +309,7 @@
w_object(PyList_GET_ITEM(v, i), p);
}
}
- else if (PyDict_Check(v)) {
+ else if (PyDict_CheckExact(v)) {
Py_ssize_t pos;
PyObject *key, *value;
w_byte(TYPE_DICT, p);
@@ -321,7 +321,7 @@
}
w_object((PyObject *)NULL, p);
}
- else if (PyAnySet_Check(v)) {
+ else if (PyAnySet_CheckExact(v)) {
PyObject *value, *it;
if (PyObject_TypeCheck(v, &PySet_Type))