Re: [bug fix??] Fishy code in tts_cirtual_copyslot()

Hi,

On 2019-09-22 14:24:36 -0400, Tom Lane wrote:
> "Tsunakawa, Takayuki" <tsunakawa(dot)takay(at)jp(dot)fujitsu(dot)com> writes:
> > In the following code in execTuples.c, shouldn' srcdesc point to the source slot's tuple descriptor? The attached fix passes make check. What kind of failure could this cause?
>
> Yeah, sure looks like a typo to me too.

Indeed, thanks for catching and pushing.

> I temporarily changed the Assert to be "==" rather than "<=", and
> it still passed check-world, so evidently we are not testing any
> cases where the descriptors are of different lengths. This explains
> the lack of symptoms.

I have a hard time seeing cases where it'd be a good idea to copy slots
of a smaller natts into a slot with larger natts. So i'm not too
surprised.

> It's still a bug though, so pushed.

Indeed.

Greetings,

Andres Freund