add missing NULL check (closes #18019)

Lib/test/test_dictviews.py

@@ -144,6 +144,11 @@ class DictSetTest(unittest.TestCase):
         self.assertEqual(d1.viewitems() ^ d3.viewitems(),
                          {('a', 1), ('b', 2), ('d', 4), ('e', 5)})
 
+    def test_recursive_repr(self):
+        d = {}
+        d[42] = d.viewvalues()
+        self.assertRaises(RuntimeError, repr, d)
+
 
 
 

Misc/NEWS

@@ -9,6 +9,9 @@ What's New in Python 2.7.6?
 Core and Builtins
 -----------------
 
+- Issue #18019: Fix crash in the repr of dictionaries containing their own
+  views.
+
 Library
 -------
 

Objects/dictobject.c

@@ -2919,6 +2919,10 @@ dictview_repr(dictviewobject *dv)
         return NULL;
 
     seq_str = PyObject_Repr(seq);
+    if (seq_str == NULL) {
+        Py_DECREF(seq);
+        return NULL;
+    }
     result = PyString_FromFormat("%s(%s)", Py_TYPE(dv)->tp_name,
                                  PyString_AS_STRING(seq_str));
     Py_DECREF(seq_str);