[Python-Dev] cpython: Add Py_RETURN_NOTIMPLEMENTED macro. Fixes #12724. (original) (raw)

Nick Coghlan ncoghlan at gmail.com
Tue Aug 16 01:39:09 CEST 2011

On Tue, Aug 16, 2011 at 9:13 AM, Ethan Furman <ethan at stoneleaf.us> wrote:

Barry Warsaw wrote:

So I'd opt for #1, unless we can agree on a better color for the bikeshed. My apologies if this is just noise, but are there RETURN macros that don't do an INCREF?

No, Py_RETURN_NONE is the only previous example, and it was added to simplify the very common idiom of:

Py_INCREF(Py_None);
return Py_None;

It was added originally because it helped to avoid two common bugs:

return Py_None; # segfault waiting to happen

return NULL; # Just plain wrong, but not picked up until tests are run and hence irritating

I'd say NotImplemented is the second most common instance of that kind of direct incref-and-return (since operator methods need to return it to correctly support type coercion), although, as Antoine noted, Py_True and Py_False would be up there as well.

Cheers, Nick.

-- Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

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