[issue26200] SETREF adds unnecessary work in some cases

[Serhiy Storchaka]

Serhiy Storchaka added the comment:

On 28.02.14 15:58, Kristján Valur Jónsson wrote:
> Also, for the equivalence to hold there is no separate Py_XSETREF, the X
> behaviour is implied, which I favour.  Enough of this X-proliferation
> already!

On 16.12.15 16:53, Random832 wrote:
> I think "SET" names imply that it's safe if the original
> reference is NULL. This isn't an objection to the names, but if
> it is given one of those names I think it should use Py_XDECREF.

It was my initial intension. But then I had got a number of voices for single macros.

On 16.12.15 23:16, Victor Stinner wrote:
> I would prefer a single macro to avoid bugs, I don't think that such
> macro has a critical impact on performances. It's more designed for
> safety, no?

On 17.12.15 08:22, Nick Coghlan wrote:
>> 1. Py_SETREF
>
> +1 if it always uses Py_XDECREF on the previous value (as I'd expect
> this to work even if the previous value was NULL)

Some objections were repeated by their authors few times. And I had no one voice for separate macros (except my).

In the light of your objection we should reraise this issue on Python-Dev.

Now, after applying patches, it would be harder to split Py_SETREF on two macros. But I tried to not replace a Py_DECREF with a Py_SETREF in performance critical code (e.g. in PyDict_SetItem).

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