Problem if is there a db error during fetch

[sdnetwork]

create or alter procedure TEST_ERROR_DURING_FETCH
returns (
MSG varchar(200))
AS
declare variable dbpath lib100;
declare variable dbpass lib100;
begin
msg = 'oupsss';
suspend;
exception raiseexception('bug');
end

for exemple if you do a select on this proc you get

wireprotocol.py", line 820, in _op_fetch_response
raise InternalError

i have have this problem on node-firebird also, and the solution is to heck the op code after each line :

        b = self.recv_channel(12)
        # op = bytes_to_bint(b[:4]) // this op is set to op_response when there is an errror
        status = bytes_to_bint(b[4:8])
        count = bytes_to_bint(b[8:])