Why does this snippet produce ORA-01002 in 10g, but works fine in 9i.

Question

While migrating from 9i to 10g, we found that one of our processes failed with ORA-01002: fetch out of sequence. Debugging produced the following example:
DECLARE
CURSOR A IS SELECT Dummy FROM Dual FOR UPDATE;
BEGIN
FOR B IN A LOOP COMMIT;  END LOOP;
END;This code works in 9i, but produces an EXCEPTION in 10g:
SQL> SELECT Banner FROM V$Version;
BANNER
Oracle9i Enterprise Edition Release 9.2.0.8.0 - Production
PL/SQL Release 9.2.0.8.0 - Production
CORE    9.2.0.8.0       Production
TNS for Linux: Version 9.2.0.8.0 - Production
NLSRTL Version 9.2.0.8.0 - Production
SQL> DECLARE
  2   CURSOR A IS SELECT Dummy FROM Dual FOR UPDATE;
  3  BEGIN
  4   FOR B IN A LOOP COMMIT;  END LOOP;
  5  END;
  6  /
PL/SQL procedure successfully completed.
SQL> SELECT Banner FROM V$Version;
BANNER
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - Prod
PL/SQL Release 10.2.0.4.0 - Production
CORE    10.2.0.4.0      Production
TNS for Linux: Version 10.2.0.4.0 - Production
NLSRTL Version 10.2.0.4.0 - Production
SQL> DECLARE
  2   CURSOR A IS SELECT Dummy FROM Dual FOR UPDATE;
  3  BEGIN
  4   FOR B IN A LOOP COMMIT;  END LOOP;
  5  END;
  6  /
DECLARE
ERROR at line 1:
ORA-01002: fetch out of sequence
ORA-06512: at line 4The documentation on the error explains this case in both 9i and more explicitly 10g. Should this have produced the EXCEPTION in 9i as well? Or, is there something else about 10g?

Answer 1

e.g. a FOR row IN cursor LOOP is now implicit using a bulk fetch operation (100 rows or so).This was also my first guess, but said optimization does not take place when the cursor is defined FOR UPDATE:
SQL> exec dbms_application_info.set_client_info(0)
PL/SQL procedure successfully completed.
SQL> declare
cursor a is select last_name, set_client_info(rownum) from employees;
begin
for b in a loop
    exit; 
end loop;
end;
PL/SQL procedure successfully completed.
SQL> select sys_context('userenv','client_info') from dual
SYS_CONTEXT('USERENV','CLIENT_INFO')                                           
100                                                                            
1 row selected.
Now with FOR UPDATE:
SQL> exec dbms_application_info.set_client_info(0)
PL/SQL procedure successfully completed.
SQL> declare
cursor a is select last_name, set_client_info(rownum) from employees for update;
begin
for b in a loop
    exit; 
end loop;
end;
PL/SQL procedure successfully completed.
SQL> select sys_context('userenv','client_info') from dual
SYS_CONTEXT('USERENV','CLIENT_INFO')                                           
1                                                                              
1 row selected.