Re: [PATCH] Exorcise "zero-dimensional" arrays (Was: Re: Should array_length() Return NULL) - Mailing list pgsql-hackers

From Brendan Jurd
Subject Re: [PATCH] Exorcise "zero-dimensional" arrays (Was: Re: Should array_length() Return NULL)
Date
Msg-id CADxJZo12kNptU5DQsUhn=pLZpuHpCwxR+C95jFiRP54Bh1EEcg@mail.gmail.com
Whole thread Raw
In response to Re: [PATCH] Exorcise "zero-dimensional" arrays (Was: Re: Should array_length() Return NULL)  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: [PATCH] Exorcise "zero-dimensional" arrays (Was: Re: Should array_length() Return NULL)  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
On 26 March 2013 22:57, Robert Haas <robertmhaas@gmail.com> wrote:
> They hate it twice as much when the change is essentially cosmetic.
> There's no functional problems with arrays as they exist today that
> this change would solve.
>

We can't sensibly test for whether an array is empty.  I'd call that a
functional problem.

The NULL return from array_{length,lower,upper,ndims} is those
functions' way of saying their arguments failed a sanity check.  So we
cannot distinguish in a disciplined way between a valid, empty array,
and bad arguments.  If the zero-D implementation had been more
polished and say, array_ndims returned zero, we had provided an
array_empty function, or the existing functions threw errors for silly
arguments instead of returning NULL, then I'd be more inclined to see
your point.  But as it stands, the zero-D implementation has always
been half-baked and slightly broken, we just got used to working
around it.

Cheers,
BJ



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