Keep getattr allive around call

Summary: We need to keep the function alive while we call it - otherwise it can be removed from the dict and go away. 3.14 already does this because it uses GetItemRef.

Reviewed By: itamaro

Differential Revision: D97773747

fbshipit-source-id: 38a7a2cddd41df95a147e356ede3c364edd6c891

Author: DinoV

Objects/moduleobject.c

@@ -810,7 +810,9 @@ _Py_module_getattro_impl(PyModuleObject *m, PyObject *name, int suppress)
     assert(m->md_dict != NULL);
     getattr = PyDict_GetItemWithError(m->md_dict, &_Py_ID(__getattr__));
     if (getattr) {
+        Py_INCREF(getattr);
         PyObject *result = PyObject_CallOneArg(getattr, name);
+        Py_DECREF(getattr);
         if (result == NULL && suppress == 1 && PyErr_ExceptionMatches(PyExc_AttributeError)) {
             // suppress AttributeError
             PyErr_Clear();