BUG #5497: plpythonu gives cache lookup error

The following bug has been logged online:

Bug reference: 5497
Logged by: David Gardner
Email address: dgardner(at)creatureshop(dot)com
PostgreSQL version: 9.0beta2
Operating system: Debian Linux
Description: plpythonu gives cache lookup error
Details:

hdpsdb=# CREATE OR REPLACE FUNCTION py_test(to_list text[])
RETURNS text AS
$BODY$
return 'here'
$BODY$
LANGUAGE 'plpythonu' VOLATILE;
CREATE FUNCTION
hdpsdb=# SELECT * FROM py_test('{"a","b","c"}');
ERROR: cache lookup failed for type 98
CONTEXT: PL/Python function "py_test"
hdpsdb=# SELECT version();
version

----------------------------------------------------------------------------
-----------------------------
PostgreSQL 9.0beta2 on x86_64-pc-linux-gnu, compiled by GCC gcc-4.4.real
(Debian 4.4.4-3) 4.4.4, 64-bit
(1 row)

hdpsdb=#