[Python-Dev] Py_SETREF vs. Py_XSETREF

Serhiy Storchaka storchaka at gmail.com
Sun Apr 3 03:32:19 EDT 2016

Originally I proposed a pair of macros for safe reference replacing to 
reflects the duality of Py_DECREF/Py_XDECREF. [1], [2]  The one should 
use Py_DECREF and the other should use Py_XDECREF.

But then I got a number of voices for the single name [3], and no one 
voice (except mine) for the pair of names. Thus in final patches the 
single name Py_SETREF that uses Py_XDECREF is used. Due to adding some 
overhead in comparison with using Py_DECREF, this macros is not used in 
critical performance code such as PyDict_SetItem().

Now Raymond says that we should have separate Py_SETREF/Py_XSETREF names 
to avoid any overhead. [4]  And so I'm raising this issue on Python-Dev.

Should we rename Py_SETREF to Py_XSETREF and introduce new Py_SETREF 
that uses Py_DECREF?

[1] http://comments.gmane.org/gmane.comp.python.devel/145346
[2] http://comments.gmane.org/gmane.comp.python.devel/145974
[3] http://bugs.python.org/issue26200#msg259784
[4] http://bugs.python.org/issue26200

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