BUG #2447: backend crashes when plpgsql functions are used in rules

The following bug has been logged online:

Bug reference: 2447
Logged by: michael crozier
Email address: crozierm(at)conducivetech(dot)com
PostgreSQL version: 8.0.7 & 8.0.3
Operating system: solaris 10 and linux
Description: backend crashes when plpgsql functions are used in rules
Details:

Using a function invocation in the WHERE expression of a RULE causes the
backend to crash.

I could not reproduce the problem on 8.1-beta4/Linux, but could reproduce it
on 8.0.5/Solaris, 8.0.7/Solaris, and 8.0.3/Linux.

Here is an example that can cause the crash:

CREATE TABLE parent ( id integer primary key);

CREATE OR REPLACE FUNCTION rule_condition(parent_row parent )
RETURNS INTEGER AS
$$
BEGIN
RETURN 0;
END;
$$ LANGUAGE 'plpgsql';

CREATE OR REPLACE RULE parent_rule AS
ON INSERT TO parent
WHERE 0=rule_condition(NEW)
DO INSTEAD ();