pg_tablespace_location() error message

The new pg_tablespace_location() function added in PG 9.2 to remove the
director location from pg_tablespace returns an odd error for '0', which
is InvalidOID:
test=> select pg_tablespace_location(0);ERROR:  could not read symbolic link "pg_tblspc/0": No such file ordirectory

Is this OK?  It handles NULL just fine:test=> select pg_tablespace_location(null);
pg_tablespace_location------------------------(1row)
 

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +