Serhiy Storchaka added the comment: > All other format codes are illegal for single argument.
I was wrong. PyObject_CallFunction() handles correctly a single non-tuple argument. The problem is only with tuple result of Py_BuildValue(). > What do you mean exactly by deprecating the feature? Emit a warning if and > only if te format string is "O" (or "S" or "N") and Py_BuildValue() returns > a tuple? Emit a FutureWarning if the format string contains the single format code and Py_BuildValue() returns a tuple. In 3.8 or 3.9 the behavior will be changed. > I dislike this path > because developers would try to make the warning quiet in Python 3.7, for > example use "(O)" format string, which is less obvious and looks like a > hack to me. PyObject_CallFunctionObjArgs(func, arg, NULL) seems obvious and perhaps even more efficient in all versions. > More and more applications use Python bleeding edge (the development branch, > default), and more and more developers quickly test their application on > the new Python stable release. Maybe we can "simply" fix the behaviour of > PyObject_CallFunction() with no transition period: Ask on Python-Dev. I afraid this is too dangerous. We should have at least one release with a FutureWarning. > Most developers don't expect the feature and so write > code which doesn't work with tuple arguments. That is why we should add a FutureWarning. If the code doesn't fail by accident, but just works incorrectly, this can be unnoticed. FutureWarning could help to fix possible bugs in older Python versions. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue28977> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
