Re: pl/perl example in the doc no longer works in 9.1

On Oct 13, 2011, at 7:09 AM, Alex Hunsaker wrote:

> On Wed, Oct 12, 2011 at 15:33, Alex Hunsaker <badalex(at)gmail(dot)com> wrote:
>> On Wed, Oct 12, 2011 at 15:00, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
>>> The core of the problem seems to be that if SvROK(sv) then
>>> the code assumes that it must be intended to convert that to an array or
>>> composite, no matter whether the declared result type of the function is
>>> compatible with such a thing.
>>
>> Hrm, well 9.0 and below did not get this "right" either:
>> create or replace function test_hash() returns text as $$ return
>> {'a'=>1}; $$ language plperl;
>> select test_array();
>> test_array
>> -----------------------
>> ARRAY(0x7fd92384dcb8)
>> (1 row)
>>
>> create or replace function test_hash() returns text as $$ return
>> {'a'=>1}; $$ language plperl;
>> select test_hash();
>> test_hash
>> ----------------------
>> HASH(0x7fd92387f848)
>> (1 row)
>>
>
>> Given the output above (both pre 9.1 and post) it seems unless the
>> type is a set or composite we should throw an error. Maybe "PL/Perl
>> function returning type %s must not return a reference" ?
>>
>>> It would be more appropriate to drive the
>>> cases off the nature of the function result type, perhaps.
>>
>> Ill see if I can cook up something that's not too invasive.
>
> PFA my attempt at a fix.
>
> This gets rid of of most of the if/else chain and the has_retval crap
> in plperl_handl_func(). Instead we let plperl_sv_to_datum() do most of
> the lifting. It also now handles VOIDOID and checks that the request
> result oid can be converted from the perl structure. For example if
> you passed in a hashref with a result oid that was not an rowtype it
> will error out with "PL/Perl cannot convert hash to non rowtype %s".
> Arrays behave similarly.
>
> One side effect is you can now return a composite literal where you
> could not before. ( We already let you return array literals )
>
> The comments might still be a bit sparse-- Im hoping the added errors
> make things a bit more self explanatory.
>
> A large portion of the diff is added regression tests, testing what
> happens when you return various references.
>
> Comments?

Looks good at first sight and passes all regression tests for me.

--
Alexey Klyukin http://www.commandprompt.com
The PostgreSQL Company – Command Prompt, Inc.