Re: Checking return value of SPI_execute

On 11/5/19 8:27 PM, Michael Paquier wrote:
> On Tue, Nov 05, 2019 at 05:21:25PM -0800, Mark Dilger wrote:
>> please find attached a patch fixing a problem previously discussed [1] about
>> the code inappropriately ignoring the return value from SPI_execute.
>>
>> I will be adding this to https://commitfest.postgresql.org/26/
>> shortly.
>
> Yes, this should be fixed.
>
>> - SPI_execute(query, true, 0);
>> + spi_result = SPI_execute(query, true, 0);
>> + if (spi_result < 0)
>> + elog(ERROR, "SPI_execute returned %s", SPI_result_code_string(spi_result));
>
> Any queries processed in xml.c are plain SELECT queries, so it seems
> to me that you need to check after SPI_OK_SELECT as only valid
> result.

Other code that checks the return value from an SPI function is
inconsistent about whether it checks for SPI_OK_SELECT or simply checks
for a negative result. I was on the fence about which precedent to
follow, and was just slightly in favor of testing for negative rather
than SPI_OK_SELECT due to this function, query_to_oid_list, taking the
query string as an argument and not controlling whether that argument is
indeed a plain SELECT.

I don't feel strongly about it.

Mark Dilger