[2.7] closes bpo-31608: Fix a crash in methods of a subclass of _collections.deque with a bad __new__(). (GH-9179)
diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py
index c81064d..e6307ab 100644
--- a/Lib/test/test_deque.py
+++ b/Lib/test/test_deque.py
@@ -659,6 +659,21 @@
d1 == d2 # not clear if this is supposed to be True or False,
# but it used to give a SystemError
+ @test_support.cpython_only
+ def test_bug_31608(self):
+ # The interpreter used to crash in specific cases where a deque
+ # subclass returned a non-deque.
+ class X(deque):
+ pass
+ d = X()
+ def bad___new__(cls, *args, **kwargs):
+ return [42]
+ X.__new__ = bad___new__
+ with self.assertRaises(TypeError):
+ d * 42 # shouldn't crash
+ with self.assertRaises(TypeError):
+ d + deque([1, 2, 3]) # shouldn't crash
+
class SubclassWithKwargs(deque):
def __init__(self, newarg=1):
diff --git a/Misc/NEWS.d/next/Library/2017-10-29-10-37-55.bpo-31608.wkp8Nw.rst b/Misc/NEWS.d/next/Library/2017-10-29-10-37-55.bpo-31608.wkp8Nw.rst
new file mode 100644
index 0000000..d657a86
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2017-10-29-10-37-55.bpo-31608.wkp8Nw.rst
@@ -0,0 +1,2 @@
+Raise a ``TypeError`` instead of crashing if a ``collections.deque`` subclass
+returns a non-deque from ``__new__``. Patch by Oren Milman.
diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 9364aba..3ca3930 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -859,11 +859,20 @@
static PyObject *
deque_copy(PyObject *deque)
{
+ PyObject *result;
if (((dequeobject *)deque)->maxlen == -1)
- return PyObject_CallFunction((PyObject *)(Py_TYPE(deque)), "O", deque, NULL);
+ result = PyObject_CallFunction((PyObject *)(Py_TYPE(deque)), "O", deque, NULL);
else
- return PyObject_CallFunction((PyObject *)(Py_TYPE(deque)), "Oi",
+ result = PyObject_CallFunction((PyObject *)(Py_TYPE(deque)), "Oi",
deque, ((dequeobject *)deque)->maxlen, NULL);
+ if (result != NULL && !PyObject_TypeCheck(result, &deque_type)) {
+ PyErr_Format(PyExc_TypeError,
+ "%.200s() must return a deque, not %.200s",
+ Py_TYPE(deque)->tp_name, Py_TYPE(result)->tp_name);
+ Py_DECREF(result);
+ return NULL;
+ }
+ return result;
}
PyDoc_STRVAR(copy_doc, "Return a shallow copy of a deque.");