Re: Uninitialized scalar variable (UNINIT) (src/backend/statistics/extended_stats.c)

On 4/12/21 6:55 PM, Ranier Vilela wrote:
> 
> 
> Em seg., 12 de abr. de 2021 às 03:04, Tom Lane <tgl@sss.pgh.pa.us
> <mailto:tgl@sss.pgh.pa.us>> escreveu:
> 
>     Michael Paquier <michael@paquier.xyz <mailto:michael@paquier.xyz>>
>     writes:
>     > On Sun, Apr 11, 2021 at 07:42:20PM -0300, Ranier Vilela wrote:
>     >> Em dom., 11 de abr. de 2021 às 16:25, Justin Pryzby
>     <pryzby@telsasoft.com <mailto:pryzby@telsasoft.com>>
>     >>> I think it's cleanest to write:
>     >>> |HeapTupleData tmptup = {0};
> 
>     > I agree that this would be cleaner.
> 
>     It would be wrong, though, or at least not have the same effect.
> 
> I think that you speak about fill pointers with 0 is not the same as
> fill pointers with NULL.
>  
> 
>     ItemPointerSetInvalid does not set the target to all-zeroes.
> 
> ItemPointerSetInvalid set or not set the target to all-zeroes?
> 

Not sure what exactly are you asking about? What Tom said is that if you
do 'struct = {0}' it sets all fields to 0, but we only want/need to set
the t_self/t_tableOid fields to 0.

> 
>     (Regardless of that detail, it's generally best to accomplish
>     objective X in the same way that existing code does.  Deciding
>     that you have a better way is often wrong, and even if you
>     are right, you should then submit a patch to change all the
>     existing cases.)
> 
> I was confused here, does the patch follow the pattern and fix the
> problem or not?
> 

I believe it does, and it's doing it in the same way as most other
similar places.

regards

-- 
Tomas Vondra
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