bpo-18533: Avoid RecursionError from repr() of recursive dictview (#4823)

dictview_repr(): Use a Py_ReprEnter() / Py_ReprLeave() pair to check
for recursion, and produce "..." if so.

test_recursive_repr(): Check for the string rather than a
RecursionError.  (Test cannot be any tighter as contents are
implementation-dependent.)

test_deeply_nested_repr(): Add new test, replacing the original
test_recursive_repr().  It checks that a RecursionError is raised in
the case of a non-recursive but deeply nested structure.  (Very
similar to what test_repr_deep() in test/test_dict.py does for a
normal dict.)

OrderedDictTests: Add new test case, to test behavior on OrderedDict
instances containing their own values() or items().
This commit is contained in:
bennorth 2018-01-26 15:46:01 +00:00 committed by Senthil Kumaran
parent e76daebc0c
commit d7773d92bd
4 changed files with 44 additions and 4 deletions

View File

@ -1,6 +1,7 @@
import collections.abc
import copy
import pickle
import sys
import unittest
class DictSetTest(unittest.TestCase):
@ -202,6 +203,20 @@ class DictSetTest(unittest.TestCase):
def test_recursive_repr(self):
d = {}
d[42] = d.values()
r = repr(d)
# Cannot perform a stronger test, as the contents of the repr
# are implementation-dependent. All we can say is that we
# want a str result, not an exception of any sort.
self.assertIsInstance(r, str)
d[42] = d.items()
r = repr(d)
# Again.
self.assertIsInstance(r, str)
def test_deeply_nested_repr(self):
d = {}
for i in range(sys.getrecursionlimit() + 100):
d = {42: d.values()}
self.assertRaises(RecursionError, repr, d)
def test_copy(self):

View File

@ -355,6 +355,20 @@ class OrderedDictTests:
self.assertEqual(repr(od),
"OrderedDict([('a', None), ('b', None), ('c', None), ('x', ...)])")
def test_repr_recursive_values(self):
OrderedDict = self.OrderedDict
od = OrderedDict()
od[42] = od.values()
r = repr(od)
# Cannot perform a stronger test, as the contents of the repr
# are implementation-dependent. All we can say is that we
# want a str result, not an exception of any sort.
self.assertIsInstance(r, str)
od[42] = od.items()
r = repr(od)
# Again.
self.assertIsInstance(r, str)
def test_setdefault(self):
OrderedDict = self.OrderedDict
pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]

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@ -0,0 +1,3 @@
``repr()`` on a dict containing its own ``values()`` or ``items()`` no
longer raises ``RecursionError``; OrderedDict similarly. Instead, use
``...``, as for other recursive structures. Patch by Ben North.

View File

@ -3853,14 +3853,22 @@ static PyObject *
dictview_repr(_PyDictViewObject *dv)
{
PyObject *seq;
PyObject *result;
PyObject *result = NULL;
Py_ssize_t rc;
rc = Py_ReprEnter((PyObject *)dv);
if (rc != 0) {
return rc > 0 ? PyUnicode_FromString("...") : NULL;
}
seq = PySequence_List((PyObject *)dv);
if (seq == NULL)
return NULL;
if (seq == NULL) {
goto Done;
}
result = PyUnicode_FromFormat("%s(%R)", Py_TYPE(dv)->tp_name, seq);
Py_DECREF(seq);
Done:
Py_ReprLeave((PyObject *)dv);
return result;
}