Enhance Argument Clinic's NoneType return converter to give void
#91284
Comments
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The attached PR makes the following possible (note that the impl has a static void
_io__IOBase_writelines_impl(PyObject *self, PyObject *lines)
/*[clinic end generated code: output=f3feca36db72dbd1 input=286ba711cb7291ad]*/Previously, the return type would be So now there is no need to track whether NULL or Py_None should be returned. Or should it be Py_RETURN_NONE? Argument Clinic does it by itself returning NULL on errors and PyNone otherwise: static PyObject *
_io__IOBase_writelines(PyObject *self, PyObject *lines)
{
PyObject *return_value = NULL;
_io__IOBase_writelines_impl(self, lines);
if (PyErr_Occurred()) {
goto exit;
}
return_value = Py_None;
Py_INCREF(Py_None);
exit:
return return_value;
} |
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The function should return different values for success and error. Functions which do not do this have bad design. |
It does, and a
Previously, a function could return NULL but forget to call |
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It is simpler and faster to return NULL than call PyErr_Occurred(). There is a special macro PY_RETURN_NONE, so there is no problem with returning None either. I do not think it would make the code better. |
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Actually, you're right. For now, PyErr_Occurred is a GIL lock plus a memory access. While the access is cheap because of a L1 cache hit, the GIL takes its toll in a hot path. So I'm closing the PR until GIL removal is done so no performance penalty will be imposed. I could use _PyErr_Occurred because "Currently Argument Clinic is considered internal-only for CPython", but it requires extra modifications of the clinic that is undesirable. |
Not relevant anymore; see #32126 (comment). |
void#32126Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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