bpo-18533: Avoid RuntimeError from repr() of recursive dictview (#4823) (#5357)
(cherry picked from commit d7773d92bd11640a8c950d6c36a9cef1cee36f96)
diff --git a/Lib/test/test_dictviews.py b/Lib/test/test_dictviews.py
index b585bdd..1edeec5 100644
--- a/Lib/test/test_dictviews.py
+++ b/Lib/test/test_dictviews.py
@@ -1,5 +1,6 @@
import copy
import pickle
+import sys
import unittest
import collections
from test import test_support
@@ -169,6 +170,20 @@
def test_recursive_repr(self):
d = {}
d[42] = d.viewvalues()
+ 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.viewitems()
+ 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.viewvalues()}
self.assertRaises(RuntimeError, repr, d)
def test_abc_registry(self):
diff --git a/Lib/test/test_ordered_dict.py b/Lib/test/test_ordered_dict.py
index 85e4841..17326c5 100644
--- a/Lib/test/test_ordered_dict.py
+++ b/Lib/test/test_ordered_dict.py
@@ -220,6 +220,19 @@
self.assertEqual(repr(od),
"OrderedDict([('a', None), ('b', None), ('c', None), ('x', ...)])")
+ def test_repr_recursive_values(self):
+ od = OrderedDict()
+ od[42] = od.viewvalues()
+ 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.viewitems()
+ r = repr(od)
+ # Again.
+ self.assertIsInstance(r, str)
+
def test_setdefault(self):
pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]
shuffle(pairs)
diff --git a/Misc/NEWS.d/next/Core and Builtins/2017-12-13-16-46-23.bpo-18533.Dlk8d7.rst b/Misc/NEWS.d/next/Core and Builtins/2017-12-13-16-46-23.bpo-18533.Dlk8d7.rst
new file mode 100644
index 0000000..2ffd571
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2017-12-13-16-46-23.bpo-18533.Dlk8d7.rst
@@ -0,0 +1,3 @@
+``repr()`` on a dict containing its own ``viewvalues()`` or
+``viewitems()`` no longer raises ``RuntimeError``. Instead, use
+``...``, as for other recursive structures. Patch by Ben North.
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index a792b2d..c544ecd 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3005,21 +3005,29 @@
{
PyObject *seq;
PyObject *seq_str;
- PyObject *result;
+ PyObject *result = NULL;
+ Py_ssize_t rc;
+ rc = Py_ReprEnter((PyObject *)dv);
+ if (rc != 0) {
+ return rc > 0 ? PyString_FromString("...") : NULL;
+ }
seq = PySequence_List((PyObject *)dv);
- if (seq == NULL)
- return NULL;
-
+ if (seq == NULL) {
+ goto Done;
+ }
seq_str = PyObject_Repr(seq);
+ Py_DECREF(seq);
+
if (seq_str == NULL) {
- Py_DECREF(seq);
- return NULL;
+ goto Done;
}
result = PyString_FromFormat("%s(%s)", Py_TYPE(dv)->tp_name,
PyString_AS_STRING(seq_str));
Py_DECREF(seq_str);
- Py_DECREF(seq);
+
+Done:
+ Py_ReprLeave((PyObject *)dv);
return result;
}