BUG #4750: UPDATE called from PL/pgSQL failed when there is ON UPDATE DO INSTEAD NOTHING rule

The following bug has been logged online:

Bug reference: 4750
Logged by: Ondrej Novy
Email address: onovy@netbox.cz
PostgreSQL version: 8.2.13
Operating system: Linux
Description: UPDATE called from PL/pgSQL failed when there is ON
UPDATE DO INSTEAD NOTHING rule
Details:

Hi,

create rule on table ON UPDATE DO INSTEAD NOTHING.
Then create function which calls UPDATE on this table.
ERROR: SPI_execute_plan failed executing query "...": Unrecognized SPI code
0
CONTEXT: PL/pgSQL function "..." line ... at SQL statement

Thank you,
Ondrej Novy