Commit ebda548d authored by unknown's avatar unknown
Browse files

Fix for BUG#7716: in in_string::set() take into account that the value returned 

by item->val_str() may be a substring of the passed string. 
Disallow string=its_substring assignment in String::operator=().


mysql-test/r/func_misc.result:
  Testcase for BUG#7716
mysql-test/t/func_misc.test:
  Testcase for BUG#7716
sql/item_cmpfunc.cc:
  Fix for BUG#7716: in in_string::set() take into account that the string returned 
  by item->val_str(S) may be not S but use the buffer owned by S.
sql/sql_string.h:
  * Added assert: String& String::operator=(const String&) may not be used to do 
    assignments like str = string_that_uses_buffer_owned_by_str
  * Added String::uses_buffer_owned_by().
parent bd556f0d

mysql-test/r/func_misc.result

+21 −0
Original line number Diff line number Diff line
@@ -28,3 +28,24 @@ length(format('nan', 2)) > 0 
select concat("$",format(2500,2));

concat("$",format(2500,2))

$2,500.00

create table t1 ( a timestamp );

insert into t1 values ( '2004-01-06 12:34' );

select a from t1 where left(a+0,6) in ( left(20040106,6) );

a

2004-01-06 12:34:00

select a from t1 where left(a+0,6) = ( left(20040106,6) );

a

2004-01-06 12:34:00

select a from t1 where right(a+0,6) in ( right(20040106123400,6) );

a

2004-01-06 12:34:00

select a from t1 where right(a+0,6) = ( right(20040106123400,6) );

a

2004-01-06 12:34:00

select a from t1 where mid(a+0,6,3) in ( mid(20040106123400,6,3) );

a

2004-01-06 12:34:00

select a from t1 where mid(a+0,6,3) = ( mid(20040106123400,6,3) );

a

2004-01-06 12:34:00

drop table t1;

mysql-test/t/func_misc.test

+15 −0
Original line number Diff line number Diff line
@@ -23,3 +23,18 @@ select length(format('nan', 2)) > 0; 
# Test for bug #628

#

select concat("$",format(2500,2));



# Test for BUG#7716

create table t1 ( a timestamp );

insert into t1 values ( '2004-01-06 12:34' );

select a from t1 where left(a+0,6) in ( left(20040106,6) );

select a from t1 where left(a+0,6) = ( left(20040106,6) );



select a from t1 where right(a+0,6) in ( right(20040106123400,6) );

select a from t1 where right(a+0,6) = ( right(20040106123400,6) );



select a from t1 where mid(a+0,6,3) in ( mid(20040106123400,6,3) );

select a from t1 where mid(a+0,6,3) = ( mid(20040106123400,6,3) );



drop table t1;

sql/item_cmpfunc.cc

+4 −0
Original line number Diff line number Diff line
@@ -1503,7 +1503,11 @@ void in_string::set(uint pos,Item *item) 
  String *str=((String*) base)+pos;

  String *res=item->val_str(str);

  if (res && res != str)

  {

    if (res->uses_buffer_owned_by(str))

      res->copy();

    *str= *res;

  }

  if (!str->charset())

  {

    CHARSET_INFO *cs;

sql/sql_string.h

+10 −0
Original line number Diff line number Diff line
@@ -182,6 +182,11 @@ class String 
  {

    if (&s != this)

    {

      /*

        It is forbidden to do assignments like 

        some_string = substring_of_that_string

       */

      DBUG_ASSERT(!s.uses_buffer_owned_by(this));

      free();

      Ptr=s.Ptr ; str_length=s.str_length ; Alloced_length=s.Alloced_length;

      alloced=0;
@@ -313,4 +318,9 @@ class String 


  /* Swap two string objects. Efficient way to exchange data without memcpy. */

  void swap(String &s);



  inline bool uses_buffer_owned_by(const String *s) const

  {

    return (s->alloced && Ptr >= s->Ptr && Ptr < s->Ptr + s->str_length);

  }

};