BUG: value in information_schema.parameters.parameter_default is always NULL for roles t

A program produces the wrong output for any given input:

Values in table *information_schema.parameters*, column *parameter_default*,
are always NULL only for roles that are not superuser.

The same column returns the correct values for superuser roles.

There is a workaround by using pg_proc table:

select
unnest(proargnames[pronargs-pronargdefaults+1:pronargs] )optargnames,
unnest(string_to_array(pg_get_expr(proargdefaults, 0)::text,','))
optargdefaults
from
pg_catalog.pg_proc
where
proname = 'proc name'

However, this approach relies on CSV parsing and will return wrong results
when the parameter default contains a comma.
--