classification
Title: Add function to get caller's name
Type: enhancement Stage: test needed
Components: Interpreter Core Versions: Python 3.10
process
Status: open Resolution:
Dependencies: Superseder:
Assigned To: Nosy List: FFY00, corona10, steve.dower, vstinner
Priority: normal Keywords:

Created on 2020-11-30 21:54 by steve.dower, last changed 2021-06-11 16:17 by corona10.

Messages (1)
msg382199 - (view) Author: Steve Dower (steve.dower) * (Python committer) Date: 2020-11-30 21:54
We have a lot of stdlib code that looks like:

    try:
        nm_tpl.__module__ = sys._getframe(2).f_globals.get('__name__', '__main__')
    except (AttributeError, ValueError):
        pass

While technically it handles sys._getframe being missing, it would be nice to handle it better for this scenario.

I'm already using a sys._get_calling_module_name() as an internal patch to avoid exposing the _getframe() calls to Python code. (As I recall, it cleans up basically all of the uses apart from the traceback module.) This lets us treat sys._getframe() calls as suspicious, because now most code never uses it.

/*[clinic input]
sys._get_calling_module_name
Return the name of the calling module.
[clinic start generated code]*/
static PyObject *
sys__get_calling_module_name_impl(PyObject *module)
/*[clinic end generated code]*/
{
    PyFrameObject *f = _PyThreadState_GET()->frame;
    PyObject *r;
    if (f == NULL) {
        Py_RETURN_NONE;
    }
    f = f->f_back;
    if (f == NULL) {
        Py_RETURN_NONE;
    }
    r = _PyDict_GetItemIdWithError(f->f_globals, &PyId___name__);
    if (!r) {
        PyErr_Clear();
        r = Py_None;
    }
    Py_INCREF(r);
    return r;
}

For something that will live beyond a separate patch, it might make sense to add as much functionality as needed for the warning module, which currently skips some importlib frames and a caller-specified count. I wouldn't want to make it too much more complex though.

Separating this out would make it easier for other implementations to support enum, typing, collections, and any other modules that want the caller's name, even if they can't easily/efficiently support a full _getframe().

Thoughts?
History
Date User Action Args
2021-06-11 16:17:34corona10setnosy: + corona10
2021-05-17 19:41:50FFY00setnosy: + FFY00
2020-11-30 21:56:18vstinnersetnosy: + vstinner
2020-11-30 21:55:02steve.dowersetstage: test needed
type: enhancement
components: + Interpreter Core
versions: + Python 3.10
2020-11-30 21:54:46steve.dowercreate