PERFORM bug with FOUND?

Kind people,

I've written a little hack, here included, which is supposed to find
whether a user is in a group.  I'd intended to do a PERFORM instead of
SELECT INTO, but PERFORM appears to set FOUND to true no matter what.
What's going on here?

The hack in question...

CREATE OR REPLACE FUNCTION in_group (text, text) RETURNS BOOLEAN AS '
DECLARE
    the_user  ALIAS FOR $1;
    the_group ALIAS FOR $2;
    dummy text; -- SELECT INTO dummy because PERFORM always returns true.
                -- Is this a bug?
BEGIN
    SELECT INTO dummy u.usename
    FROM
      pg_user u
    , pg_group g
    WHERE
        u.usename = the_user
    AND g.groname = the_group
    AND u.usesysid = ANY (g.grolist);

    IF FOUND
    THEN
        RETURN true;
    ELSE
        RETURN false;
    END IF;
END;
' LANGUAGE 'plpgsql' STRICT IMMUTABLE;

TIA for any hints, tips or pointers :)

Cheers,
D
--
David Fetter david@fetter.org http://fetter.org/
phone: +1 510 893 6100    cell: +1 415 235 3778

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