Re: empty array can crash backend using int_array_enum from contrib.

On 2005-04-23, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Ron Mayer <rm_pg@cheapcomplexdevices.com> writes:
>> Using the int_array_enum function from contrib/intagg I can crash the
>> 8.0.2 backend when I pass it an empty array.
>
> Man, we've had a few problems with that thing, haven't we?
>
> I patched it along these lines:
[snip]

We were discussing this one on irc while it was presumably waiting in the
moderation queue, and I suggested to the poster an alternative patch that
allowed empty arrays to actually be treated as empty (your version will
error out on int_array_enum('{}') rather than producing 0 rows, which seems
unhelpful). I would suggest changing your test from != 1 to > 1, and adding
the moral equivalent of:

--- int_aggregate.c.orig        Fri Apr 22 11:37:09 2005
+++ int_aggregate.c     Fri Apr 22 11:44:34 2005
@@ -227,7 +227,7 @@
        else    /* use an existing one */
                pc = (CTX *) fcinfo->context;
        /* Are we done yet? */
-       if (pc->num >= pc->p->items)
+       if (ARR_NDIM(pc->p) != 1 || pc->num >= pc->p->items)
        {
                /* We are done */
                if (pc->flags & TOASTED)

(that test could be moved into the setup phase, of course)

--
Andrew, Supernews
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