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Bug#46815 CONCAT_WS returning wrong data

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The problem is that argument buffer can be used as result buffer
and it leads to argument value change.
The fix is to use 'old buffer' as result buffer only
if first argument is not constant item.


mysql-test/r/func_str.result:
  test result
mysql-test/t/func_str.test:
  test case
sql/item_strfunc.cc:
  The problem is that argument buffer can be used as result buffer
  and it leads to argument value change.
  The fix is to use 'old buffer' as result buffer only
  if first argument is not constant item.
This commit is contained in:
Sergey Glukhov 2009-09-10 15:24:07 +05:00
parent 24f103e39c
commit 10406ae658
3 changed files with 28 additions and 1 deletions
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9
mysql-test/r/func_str.result
View File

@ -2196,4 +2196,13 @@ SELECT LOAD_FILE(a) FROM t1;
LOAD_FILE(a)
NULL
DROP TABLE t1;
CREATE TABLE t1 (f2 VARCHAR(20));
CREATE TABLE t2 (f2 VARCHAR(20));
INSERT INTO t1 VALUES ('MIN'),('MAX');
INSERT INTO t2 VALUES ('LOAD');
SELECT CONCAT_WS('_', (SELECT t2.f2 FROM t2), t1.f2) AS concat_name FROM t1;
concat_name
LOAD_MIN
LOAD_MAX
DROP TABLE t1, t2;
End of 5.0 tests

13
mysql-test/t/func_str.test
View File

@ -1177,5 +1177,18 @@ INSERT INTO t1 VALUES ('aaaaaaaa');
SELECT LOAD_FILE(a) FROM t1;
DROP TABLE t1;
#
# Bug#46815 CONCAT_WS returning wrong data
#
CREATE TABLE t1 (f2 VARCHAR(20));
CREATE TABLE t2 (f2 VARCHAR(20));
INSERT INTO t1 VALUES ('MIN'),('MAX');
INSERT INTO t2 VALUES ('LOAD');
SELECT CONCAT_WS('_', (SELECT t2.f2 FROM t2), t1.f2) AS concat_name FROM t1;
DROP TABLE t1, t2;
--echo End of 5.0 tests

7
sql/item_strfunc.cc
View File

@ -600,6 +600,7 @@ String *Item_func_concat_ws::val_str(String *str)
String tmp_sep_str(tmp_str_buff, sizeof(tmp_str_buff),default_charset_info),
*sep_str, *res, *res2,*use_as_buff;
uint i;
bool is_const= 0;
null_value=0;
if (!(sep_str= args[0]->val_str(&tmp_sep_str)))
@ -613,7 +614,11 @@ String *Item_func_concat_ws::val_str(String *str)
// If not, return the empty string
for (i=1; i < arg_count; i++)
if ((res= args[i]->val_str(str)))
{
is_const= args[i]->const_item() || !args[i]->used_tables();
break;
}
if (i == arg_count)
return &my_empty_string;
@ -631,7 +636,7 @@ String *Item_func_concat_ws::val_str(String *str)
current_thd->variables.max_allowed_packet);
goto null;
}
if (res->alloced_length() >=
if (!is_const && res->alloced_length() >=
res->length() + sep_str->length() + res2->length())
{ // Use old buffer
res->append(*sep_str); // res->length() > 0 always