Puzzling behaviour of Py_IncRef

[Chris Angelico]

On Fri, 21 Jan 2022 at 10:10, Greg Ewing <greg.ewing at canterbury.ac.nz> wrote:
>
> On 20/01/22 12:09 am, Chris Angelico wrote:
> > At this point, the refcount has indeed been increased.
> >
> >>           return self;
> >>      }
> >
> > And then you say "my return value is this object".
> >
> > So you're incrementing the refcount, then returning it without
> > incrementing the refcount. Your code is actually equivalent to "return
> > self".
>
> Chris, you're not making any sense. This is C code, so there's no
> way that "return x" can change the reference count of x.

Yeah, I wasn't clear there. It was equivalent to *the Python code*
"return self". My apologies.

>  > The normal thing to do is to add a reference to whatever you're
>  > returning. For instance, Py_RETURN_NONE will incref None and then
>  > return it.
>  >
>
> The OP understands that this is not a normal thing to do. He's
> trying to deliberately leak a reference for the purpose of diagnosing
> a problem.
>
> It would be interesting to see what the actual refcount is after
> calling this function.
>

Yes, and that's why I was saying it would need a *second* incref.

ChrisA