Commit c04d3727 authored by igor@olga.mysql.com's avatar igor@olga.mysql.com
Browse files

Fixed bug #27545. 

Both arguments of the function NAME_CONST must be constant expressions.
This constraint is checked in the Item_name_const::fix_fields method. 
Yet if the argument of the function was not a constant expression no
error message was reported. As a result the client hanged waiting for a
response.
Now the function Item_name_const::fix_fields reports an error message
when any of the additional context conditions imposed on the function
NAME_CONST is not satisfied.
parent 987ec3f3

mysql-test/r/func_misc.result

+5 −0
Original line number Diff line number Diff line
@@ -207,4 +207,9 @@ test 
SELECT NAME_CONST('test', 'test');

test

test

CREATE TABLE t1 (a int);

INSERT INTO t1 VALUES (5), (2);

SELECT NAME_CONST(x,2) FROM (SELECT a x FROM t1) t;

ERROR HY000: The 'NAME_CONST' syntax is reserved for purposes internal to the MySQL server

DROP TABLE t1;

End of 5.0 tests

mysql-test/t/func_misc.test

+13 −0
Original line number Diff line number Diff line
@@ -204,5 +204,18 @@ SELECT NAME_CONST('test', 1.0); 
SELECT NAME_CONST('test', -1.0);

SELECT NAME_CONST('test', 'test');



#

# Bug #27545: erroneous usage of NAME_CONST with a name as the first parameter 

#             resolved against a column name of a derived table hangs the client

#



CREATE TABLE t1 (a int);

INSERT INTO t1 VALUES (5), (2);



--error ER_RESERVED_SYNTAX

SELECT NAME_CONST(x,2) FROM (SELECT a x FROM t1) t;



DROP TABLE t1;



--echo End of 5.0 tests

sql/item.cc

+7 −7
Original line number Diff line number Diff line
@@ -1221,14 +1221,14 @@ bool Item_name_const::fix_fields(THD *thd, Item **ref) 
  s.length(0);



  if (value_item->fix_fields(thd, &value_item) ||

      name_item->fix_fields(thd, &name_item))

    return TRUE;

  if (!(value_item->const_item() && name_item->const_item()))

      name_item->fix_fields(thd, &name_item) ||

      !value_item->const_item() ||

      !name_item->const_item() ||

      !(item_name= name_item->val_str(&s))) // Can't have a NULL name 

  {

    my_error(ER_RESERVED_SYNTAX, MYF(0), "NAME_CONST");

    return TRUE;



  if (!(item_name= name_item->val_str(&s)))

    return TRUE; /* Can't have a NULL name */



  }

  set_name(item_name->ptr(), (uint) item_name->length(), system_charset_info);

  max_length= value_item->max_length;

  decimals= value_item->decimals;