Problem with 'get current diagnostics'

create or replace function EXECUTE_WO_RETURN_LOGGED(
    I_STATEMENT_TO_EXECUTE  in  text,
    I_LEVEL                 in  text        default 'LOG',
    I_REPORT_ERRORS_ONLY    in  boolean     default false
)
  returns bigint
  language plpgsql
  security invoker
  volatile
  set search_path = --current user,
                    :SCHEMA_NAME_LOGGER,
                    :SCHEMA_NAME,
                    :SCHEMA_NAME_UTILS,
                    public
  as
$body$
    declare
        -- Constants
        C_LB                constant            varchar(2) default e'\n';

        -- Variables
        V_TEXT                                  text;
        V_REC                                   record;
        V_ROW_COUNT                             bigint
          default 0;
        V_EXCEPTION_OCCURRED                    boolean
          default false;
        V_SQLSTATE                              char(5);
        V_STACK                                 text
          default '!!!no data found!!!';
        V_DETAILS                               text
          default '!!!no data found!!!';
        V_HINT                                  text
          default '!!!no data found!!!';
    begin
        execute I_STATEMENT_TO_EXECUTE;
        get current diagnostics V_ROW_COUNT = ROW_COUNT;
        V_TEXT :=
          'Following statement has been executed successfully affecting ';
        case V_ROW_COUNT
            when 0 then
                V_TEXT := V_TEXT || ' no row.';
            when 1 then
                V_TEXT := V_TEXT || ROW_COUNT || ' row.';
            else
                V_TEXT := V_TEXT || ROW_COUNT || ' rows.';
        end case;
        V_TEXT := V_TEXT || C_LB || C_LB || '-- Statement' || C_LB ||
          I_STATEMENT_TO_EXECUTE;
        case I_LEVEL
            when 'DEBUG' then
                perform DEBUG(I_MESSAGE => V_TEXT) ;
            when 'LOG' then
                perform LOG(I_MESSAGE => V_TEXT) ;
            when 'INFO' then
                perform INFO(I_MESSAGE => V_TEXT) ;
            when 'NOTICE' then
                perform NOTICE(I_MESSAGE => V_TEXT) ;
            when 'WARNING' then
                perform WARNING(I_MESSAGE => V_TEXT) ;
            when 'EXCEPTION' then   -- maybe pointless but there you go ;-)
                perform EXCEPTION(I_MESSAGE => V_TEXT) ;
            else
                raise exception '%', 'Unsupported level ' || I_LEVEL;
        end case;
        return V_ROW_COUNT;
     exception
        when others then
            if I_REPORT_ERRORS_ONLY then
                get stacked diagnostics V_DETAILS = PG_EXCEPTION_DETAIL;
                get stacked diagnostics V_HINT = PG_EXCEPTION_HINT;
                get stacked diagnostics V_STACK = PG_EXCEPTION_CONTEXT;
                perform WARNING(
                    I_MESSAGE       => GET_FORMATTED_EXCEPTION_MESSAGE(
                                           I_STATEMENT_WITH_PARAMETERS  =>
                                             I_STATEMENT_TO_EXECUTE,
                                           I_SQLSTATE                   =>
                                             SQLSTATE,
                                           I_SQLERRM                    =>
                                             SQLERRM,
                                           I_DETAILS                    =>
                                             V_DETAILS,
                                           I_HINT                       =>
                                             V_HINT,
                                           I_STACK                      =>
                                             V_STACK
                                       )
                );
                return null;
            else
                raise;
            end if;
    end;
$body$;