diff --git a/Misc/NEWS b/Misc/NEWS index 0111cb43fc1..48074416911 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -9,6 +9,9 @@ What's New in Python 2.7.4 Core and Builtins ----------------- +- Issue #16839: Fix a segfault when calling unicode() on a classic class early + in interpreter initialization. + - Issue #16761: Calling ``int()`` and ``long()`` with *base* argument only now raises TypeError. diff --git a/Objects/object.c b/Objects/object.c index e732dceff64..14f4e9f6114 100644 --- a/Objects/object.c +++ b/Objects/object.c @@ -474,7 +474,7 @@ PyObject_Unicode(PyObject *v) PyObject *func; PyObject *str; int unicode_method_found = 0; - static PyObject *unicodestr; + static PyObject *unicodestr = NULL; if (v == NULL) { res = PyString_FromString(""); @@ -491,6 +491,11 @@ PyObject_Unicode(PyObject *v) if (PyInstance_Check(v)) { /* We're an instance of a classic class */ /* Try __unicode__ from the instance -- alas we have no type */ + if (!unicodestr) { + unicodestr = PyString_InternFromString("__unicode__"); + if (!unicodestr) + return NULL; + } func = PyObject_GetAttr(v, unicodestr); if (func != NULL) { unicode_method_found = 1;