| From: | Jim Nasby <Jim(dot)Nasby(at)BlueTreble(dot)com> | 
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Robert Haas <robertmhaas(at)gmail(dot)com> | 
| Cc: | Pg Hackers <pgsql-hackers(at)postgresql(dot)org> | 
| Subject: | Re: Bad behavior from plpython 'return []' | 
| Date: | 2016-07-01 20:34:58 | 
| Message-ID: | 6449df87-e606-e6a4-e25d-42ce6ffb78d9@BlueTreble.com | 
| Views: | Whole Thread | Raw Message | Download mbox | Resend email | 
| Thread: | |
| Lists: | pgsql-hackers | 
On 7/1/16 2:52 PM, Tom Lane wrote:
> +	/* if caller tries to specify zero-length array, make it empty */
> +	if (nelems <= 0)
> +		return construct_empty_array(elmtype);
> +
> 	/* compute required space */
> 	nbytes = 0;
> 	hasnulls = false;
>
> But that might introduce new problems too, if any callers expect the
> array dimensions to be exactly what they asked for.
You mean ndims? What if instead of an empty array it returned an array 
where *dims was just all zeros (and correctly set *lbs)? array_eq would 
still need to account for that, but I think we don't have a choice about 
that unless we expressly forbid arrays where any of the elements of 
*dims were 0 (which I suspect we should probably do anyway... I don't 
see how you can do anything with a 2x0x3 array...)
-- 
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com
855-TREBLE2 (855-873-2532)   mobile: 512-569-9461
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