[3.13] gh-127190: Fix local_setattro() error handling (GH-127366) (#127367)

gh-127190: Fix local_setattro() error handling (GH-127366)

Don't make the assumption that the 'name' argument is a string. Use
repr() to format the 'name' argument instead.
(cherry picked from commit 20657fbdb1)

Co-authored-by: Victor Stinner <vstinner@python.org>

Modules/_threadmodule.c

@@ -1688,7 +1688,7 @@ local_setattro(localobject *self, PyObject *name, PyObject *v)
     }
     if (r == 1) {
         PyErr_Format(PyExc_AttributeError,
-                     "'%.100s' object attribute '%U' is read-only",
+                     "'%.100s' object attribute %R is read-only",
                      Py_TYPE(self)->tp_name, name);
         goto err;
     }