- Issue #1686386: Tuple's tp_repr did not take into account the possibility of
having a self-referential tuple, which is possible from C code. Nor did
object's tp_str consider that a type's tp_str could do something that could
lead to an inifinite recursion. Py_ReprEnter() and Py_EnterRecursiveCall(),
respectively, fixed the issues. (Backport of r58288 from trunk to 2.5.)
diff --git a/Objects/object.c b/Objects/object.c
index 71e5641..af7be01 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -403,7 +403,12 @@
if (v->ob_type->tp_str == NULL)
return PyObject_Repr(v);
+ /* It is possible for a type to have a tp_str representation that loops
+ infinitely. */
+ if (Py_EnterRecursiveCall(" while getting the str of an object"))
+ return NULL;
res = (*v->ob_type->tp_str)(v);
+ Py_LeaveRecursiveCall();
if (res == NULL)
return NULL;
type_ok = PyString_Check(res);
@@ -2141,4 +2146,3 @@
#ifdef __cplusplus
}
#endif
-
diff --git a/Objects/tupleobject.c b/Objects/tupleobject.c
index 6f3711f..56a1024 100644
--- a/Objects/tupleobject.c
+++ b/Objects/tupleobject.c
@@ -208,6 +208,15 @@
PyObject *s, *temp;
PyObject *pieces, *result = NULL;
+ /* While not mutable, it is still possible to end up with a cycle in a
+ tuple through an object that stores itself within a tuple (and thus
+ infinitely asks for the repr of itself). This should only be
+ possible within a type. */
+ i = Py_ReprEnter((PyObject *)v);
+ if (i != 0) {
+ return i > 0 ? PyString_FromString("(...)") : NULL;
+ }
+
n = v->ob_size;
if (n == 0)
return PyString_FromString("()");
@@ -218,7 +227,10 @@
/* Do repr() on each element. */
for (i = 0; i < n; ++i) {
+ if (Py_EnterRecursiveCall(" while getting the repr of a tuple"))
+ goto Done;
s = PyObject_Repr(v->ob_item[i]);
+ Py_LeaveRecursiveCall();
if (s == NULL)
goto Done;
PyTuple_SET_ITEM(pieces, i, s);
@@ -253,6 +265,7 @@
Done:
Py_DECREF(pieces);
+ Py_ReprLeave((PyObject *)v);
return result;
}