pl/perl not rethrowing pl/pgsql exceptions

is this behavior correct?

create or replace function error() returns text as
$$
begin
raise exception 'test!';
end;
$$ language plpgsql;

create or replace function test() returns text as
$$
my $res = spi_query("select error()"); # this error is ignored
my $res = spi_query("something stupid!"); # this is not?
$$ language plperlu;

merlin