Issue 24051: Argument Clinic no longer works with single optional argument (original) (raw)

Created on 2015-04-24 13:48 by serhiy.storchaka, last changed 2022-04-11 14:58 by admin. This issue is now closed.

Messages (6)
msg241943 - (view)	Author: Serhiy Storchaka (serhiy.storchaka) *	Date: 2015-04-24 13:48
Argument Clinic no longer works single optional argument. For example see _tkinter.tkapp.wantobjects in the patch in . /*[clinic input] _tkinter.tkapp.wantobjects [ value: int ] / [clinic start generated code]*/ It is converted to the methoddef of type METH_O. #define _TKINTER_TKAPP_WANTOBJECTS_METHODDEF \ {"wantobjects", (PyCFunction)_tkinter_tkapp_wantobjects, METH_O, _tkinter_tkapp_wantobjects__doc__}, static PyObject * _tkinter_tkapp_wantobjects(PyObject *self, PyObject *arg) { PyObject *return_value = NULL; int group_right_1 = 0; int value = 0; if (!PyArg_Parse(arg, "i:wantobjects", &value)) goto exit; return_value = _tkinter_tkapp_wantobjects_impl(self, group_right_1, value); exit: return return_value; } As result wantobjects() can't be called without an argument.
msg242500 - (view)	Author: Larry Hastings (larry) *	Date: 2015-05-03 18:56
Optional groups were designed to support two specific legacy use cases: * functions that have groups of parameters that are * functions with optional parameters to the left of required parameters They are not intended to be used in cases like this. I really, really wish you would stop using them except for these specific legacy cases. Furthermore, the argument parsing for tkinter.tkapp.wantobjects has a very clear translation into Argument Clinic: value: int = -1 / Optional groups should not be used for single-argument functions. I have no interest in fixing this bug.
msg242501 - (view)	Author: Larry Hastings (larry) *	Date: 2015-05-03 18:59
Sorry, I forgot to finish the first bullet point. It should have read: * functions that have groups of parameters that are optional only as a group (e.g. curses.window.getch)
msg242515 - (view)	Author: Serhiy Storchaka (serhiy.storchaka) *	Date: 2015-05-03 20:11
Then it would be better to not convert wantobjects() to Argument Clinic. Using -1 as a value for not passed argument is a hack (added in 1ab9978123be) and I don't want to propagate it to the signature. But I afraid that there are other functions that suffer from this bug (may be in the curses module).
msg242516 - (view)	Author: Larry Hastings (larry) *	Date: 2015-05-03 20:14
If the argument currently uses a default value of -1, then I see no problem with converting it to Argument Clinic using a default value of -1. If you claim it's a "hack" then you should discuss that with the author of 1ab9978123be.
msg242517 - (view)	Author: Larry Hastings (larry) *	Date: 2015-05-03 20:14
Closing as wontfix. This is not a supported use of optional groups.