Fix bug

Author: matthiasgoergens

Lib/test/test_deque.py

@@ -1076,6 +1076,18 @@ def test_slice_preserves_subclass(self, dq, start, stop, step):
         self.assertEqual(list(view), expected)
         self.assertEqual(view.maxlen, d.maxlen)
 
+    @hypothesis.given(items=st.lists(st.integers()), maxlen=st.integers(min_value=0))
+    def test_slice_and_copy_preserve_large_maxlen(self, items, maxlen):
+        d = Deque(items, maxlen)
+
+        sliced = d[:]
+        self.assertIsInstance(sliced, Deque)
+        self.assertEqual(sliced.maxlen, maxlen)
+
+        copied = d.copy()
+        self.assertIsInstance(copied, Deque)
+        self.assertEqual(copied.maxlen, maxlen)
+
     def test_basics(self):
         d = Deque(range(25))
         d.__init__(range(200))

Modules/_collectionsmodule.c

@@ -647,8 +647,8 @@ deque_copy_impl(dequeobject *deque)
         result = PyObject_CallOneArg((PyObject *)(Py_TYPE(deque)),
                                      (PyObject *)deque);
     else
-        result = PyObject_CallFunction((PyObject *)(Py_TYPE(deque)), "Oi",
-                                       deque, old_deque->maxlen, NULL);
+        result = PyObject_CallFunction((PyObject *)(Py_TYPE(deque)), "On",
+                                       deque, old_deque->maxlen);
     if (result != NULL && !PyObject_TypeCheck(result, state->deque_type)) {
         PyErr_Format(PyExc_TypeError,
                      "%.200s() must return a deque, not %.200s",
@@ -1314,8 +1314,8 @@ deque_slice_lock_held(dequeobject *deque, PyObject *slice)
         result = PyObject_CallOneArg((PyObject *)(Py_TYPE(deque)), values);
     }
     else {
-        result = PyObject_CallFunction((PyObject *)(Py_TYPE(deque)), "Oi",
-                                       values, deque->maxlen, NULL);
+        result = PyObject_CallFunction((PyObject *)(Py_TYPE(deque)), "On",
+                                       values, deque->maxlen);
     }
     Py_DECREF(values);
     if (result != NULL && !PyObject_TypeCheck(result, state->deque_type)) {