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[3.7] bpo-34574: Prevent OrderedDict iterators from exhaustion during pickling. (GH-9051) #9996

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Merged
miss-islington merged 1 commit into from
Oct 20, 2018
+28 −28
Merged

[3.7] bpo-34574: Prevent OrderedDict iterators from exhaustion during pickling. (GH-9051) #9996

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17 changes: 17 additions & 0 deletions Lib/test/test_ordered_dict.py
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Original file line number Diff line number Diff line change
Expand Up @@ -732,6 +732,23 @@ def test_key_change_during_iteration(self):
del od['c']
self.assertEqual(list(od), list('bdeaf'))

def test_iterators_pickling(self):
OrderedDict = self.OrderedDict
pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]
od = OrderedDict(pairs)

for method_name in ('keys', 'values', 'items'):
meth = getattr(od, method_name)
expected = list(meth())[1:]
for i in range(pickle.HIGHEST_PROTOCOL + 1):
with self.subTest(method_name=method_name, protocol=i):
it = iter(meth())
next(it)
p = pickle.dumps(it, i)
unpickled = pickle.loads(p)
self.assertEqual(list(unpickled), expected)
self.assertEqual(list(it), expected)


class PurePythonOrderedDictSubclassTests(PurePythonOrderedDictTests):

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2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Library/2018-09-04-09-32-54.bpo-34574.X4RwYI.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
OrderedDict iterators are not exhausted during pickling anymore. Patch by
Sergey Fedoseev.
37 changes: 9 additions & 28 deletions Objects/odictobject.c
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Expand Up @@ -1837,38 +1837,19 @@ PyDoc_STRVAR(reduce_doc, "Return state information for pickling");
static PyObject *
odictiter_reduce(odictiterobject *di)
{
PyObject *list, *iter;

list = PyList_New(0);
if (!list)
return NULL;
/* copy the iterator state */
odictiterobject tmp = *di;
Py_XINCREF(tmp.di_odict);
Py_XINCREF(tmp.di_current);

/* iterate the temporary into a list */
for(;;) {
PyObject *element = odictiter_iternext(di);
if (element) {
if (PyList_Append(list, element)) {
Py_DECREF(element);
Py_DECREF(list);
return NULL;
}
Py_DECREF(element);
}
else {
/* done iterating? */
break;
}
}
if (PyErr_Occurred()) {
Py_DECREF(list);
return NULL;
}
iter = _PyObject_GetBuiltin("iter");
if (iter == NULL) {
Py_DECREF(list);
PyObject *list = PySequence_List((PyObject*)&tmp);
Py_XDECREF(tmp.di_odict);
Py_XDECREF(tmp.di_current);
if (list == NULL) {
return NULL;
}
return Py_BuildValue("N(N)", iter, list);
return Py_BuildValue("N(N)", _PyObject_GetBuiltin("iter"), list);
}

static PyMethodDef odictiter_methods[] = {
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