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Bug#11753363 (bug#44793) CHARACTER SETS: CASE CLAUSE, UCS2 OR UTF32, FAILURE

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Problem: in case of string CASE/WHEN arguments with different
character sets, Item_func_case::find_item() called comparator
cmp_items[x] on mixed character set Items, so a 8-bit value could
be errouneously referenced to as being utf16/utf32 value,
which led to crash on DBUG_ASSERT() because of wrong value length.
This was wrong, as string comparator expects arguments in the same
character set.

Fix: modify Item_func_case's argument list after calling
agg_arg_charsets_for_comparison() - put the Items in "agg" array
back to "args", because some of the Items in the "agg" array might
have been changed to character set converters:
- to Item_func_conv_charset for non-constant items
- to Item_string for constant items

In other words, perform the same substitution which is done in
all other operations string comparison or string result operations:

Replace
  CASE         latin1_item              WHEN utf16_item THEN ... END
to
  CASE CONVERT(latin1_item USING utf16) WHEN utf16_item THEN ... END

Replace
  CASE utf16_item WHEN         latin1_item              THEN ... END
to
  CASE utf16_item WHEN CONVERT(latin1_item USING utf16) THEN ... END


  @ mysql-test/r/ctype_utf16.result
  @ mysql-test/r/ctype_utf32.result
  @ mysql-test/t/ctype_utf16.test
  @ mysql-test/t/ctype_utf32.test
  Adding tests

  @ sql/item_cmpfunc.cc
  Put "agg" back to "args".

  @ sql/sql_string.cc
  Backporting a fix for String::set_or_copy_aligned() from 5.6,
  for better test coverage:
  "SELECT _utf16 0x61" should expand the string to 0x0061 rather
  than to 0x000061.
  This fix was made in 5.6 under terms of "WL#4616 Implement UTF16-LE".
This commit is contained in:
Alexander Barkov 2011-03-01 15:09:37 +03:00
parent 48126a574c
commit 8a83d30436
6 changed files with 97 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
mysql-test/r/ctype_utf16.result
View File

@ -30,13 +30,13 @@ binary 'a a' > 'a' binary 'a \0' > 'a' binary 'a\0' > 'a'
1 1 1
select hex(_utf16 0x44);
hex(_utf16 0x44)
00000044
0044
select hex(_utf16 0x3344);
hex(_utf16 0x3344)
3344
select hex(_utf16 0x113344);
hex(_utf16 0x113344)
000000113344
00113344
CREATE TABLE t1 (word VARCHAR(64), word2 CHAR(64)) CHARACTER SET utf16;
INSERT INTO t1 VALUES (_koi8r 0xF2, _koi8r 0xF2), (X'2004',X'2004');
SELECT hex(word) FROM t1 ORDER BY word;
@ -434,10 +434,10 @@ aardvarz
DROP TABLE t1;
SELECT hex(cast(0xAA as char character set utf16));
hex(cast(0xAA as char character set utf16))
000000AA
00AA
SELECT hex(convert(0xAA using utf16));
hex(convert(0xAA using utf16))
000000AA
00AA
CREATE TABLE t1 (a char(10) character set utf16);
INSERT INTO t1 VALUES (0x1),(0x11),(0x111),(0x1111),(0x11111);
SELECT HEX(a) FROM t1;
@ -1102,5 +1102,20 @@ t2 CREATE TABLE `t2` (
) ENGINE=MyISAM DEFAULT CHARSET=latin1
DROP TABLE t1, t2;
#
# Bug#11753363 (Bug#44793) Character sets: case clause, ucs2 or utf32, failure
#
SELECT CASE _latin1'a' WHEN _utf16'a' THEN 'A' END;
CASE _latin1'a' WHEN _utf16'a' THEN 'A' END
A
SELECT CASE _utf16'a' WHEN _latin1'a' THEN 'A' END;
CASE _utf16'a' WHEN _latin1'a' THEN 'A' END
A
CREATE TABLE t1 (s1 CHAR(5) CHARACTER SET utf16);
INSERT INTO t1 VALUES ('a');
SELECT CASE s1 WHEN 'a' THEN 'b' ELSE 'c' END FROM t1;
CASE s1 WHEN 'a' THEN 'b' ELSE 'c' END
b
DROP TABLE t1;
#
# End of 5.5 tests
#

15
mysql-test/r/ctype_utf32.result
View File

@ -1152,5 +1152,20 @@ d
f
DROP TABLE t1;
#
# Bug#11753363 (Bug#44793) Character sets: case clause, ucs2 or utf32, failure
#
SELECT CASE _latin1'a' WHEN _utf32'a' THEN 'A' END;
CASE _latin1'a' WHEN _utf32'a' THEN 'A' END
A
SELECT CASE _utf32'a' WHEN _latin1'a' THEN 'A' END;
CASE _utf32'a' WHEN _latin1'a' THEN 'A' END
A
CREATE TABLE t1 (s1 CHAR(5) CHARACTER SET utf32);
INSERT INTO t1 VALUES ('a');
SELECT CASE s1 WHEN 'a' THEN 'b' ELSE 'c' END FROM t1;
CASE s1 WHEN 'a' THEN 'b' ELSE 'c' END
b
DROP TABLE t1;
#
# End of 5.5 tests
#

9
mysql-test/t/ctype_utf16.test
View File

@ -745,6 +745,15 @@ CREATE TABLE t2 AS SELECT CONCAT(s1) FROM t1;
SHOW CREATE TABLE t2;
DROP TABLE t1, t2;
--echo #
--echo # Bug#11753363 (Bug#44793) Character sets: case clause, ucs2 or utf32, failure
--echo #
SELECT CASE _latin1'a' WHEN _utf16'a' THEN 'A' END;
SELECT CASE _utf16'a' WHEN _latin1'a' THEN 'A' END;
CREATE TABLE t1 (s1 CHAR(5) CHARACTER SET utf16);
INSERT INTO t1 VALUES ('a');
SELECT CASE s1 WHEN 'a' THEN 'b' ELSE 'c' END FROM t1;
DROP TABLE t1;
#
## TODO: add tests for all engines

10
mysql-test/t/ctype_utf32.test
View File

@ -830,6 +830,16 @@ INSERT INTO t1 VALUES ('d'),('f');
SELECT * FROM t1 WHERE b BETWEEN 'a' AND 'z';
DROP TABLE t1;
--echo #
--echo # Bug#11753363 (Bug#44793) Character sets: case clause, ucs2 or utf32, failure
--echo #
SELECT CASE _latin1'a' WHEN _utf32'a' THEN 'A' END;
SELECT CASE _utf32'a' WHEN _latin1'a' THEN 'A' END;
CREATE TABLE t1 (s1 CHAR(5) CHARACTER SET utf32);
INSERT INTO t1 VALUES ('a');
SELECT CASE s1 WHEN 'a' THEN 'b' ELSE 'c' END FROM t1;
DROP TABLE t1;
--echo #
--echo # End of 5.5 tests
--echo #

45
sql/item_cmpfunc.cc
View File

@ -3054,20 +3054,59 @@ void Item_func_case::fix_length_and_dec()
agg[0]= args[first_expr_num];
left_result_type= agg[0]->result_type();
/*
As the first expression and WHEN expressions
are intermixed in args[] array THEN and ELSE items,
extract the first expression and all WHEN expressions into
a temporary array, to process them easier.
*/
for (nagg= 0; nagg < ncases/2 ; nagg++)
agg[nagg+1]= args[nagg*2];
nagg++;
if (!(found_types= collect_cmp_types(agg, nagg)))
return;
if (found_types & (1 << STRING_RESULT))
{
/*
If we'll do string comparison, we also need to aggregate
character set and collation for first/WHEN items and
install converters for some of them to cmp_collation when necessary.
This is done because cmp_item compatators cannot compare
strings in two different character sets.
Some examples when we install converters:
1. Converter installed for the first expression:
CASE latin1_item WHEN utf16_item THEN ... END
is replaced to:
CASE CONVERT(latin1_item USING utf16) WHEN utf16_item THEN ... END
2. Converter installed for the left WHEN item:
CASE utf16_item WHEN latin1_item THEN ... END
is replaced to:
CASE utf16_item WHEN CONVERT(latin1_item USING utf16) THEN ... END
*/
if (agg_arg_charsets_for_comparison(cmp_collation, agg, nagg))
return;
/*
Now copy first expression and all WHEN expressions back to args[]
arrray, because some of the items might have been changed to converters
(e.g. Item_func_conv_charset, or Item_string for constants).
*/
args[first_expr_num]= agg[0];
for (nagg= 0; nagg < ncases / 2; nagg++)
args[nagg * 2]= agg[nagg + 1];
}
for (i= 0; i <= (uint)DECIMAL_RESULT; i++)
{
if (found_types & (1 << i) && !cmp_items[i])
{
DBUG_ASSERT((Item_result)i != ROW_RESULT);
if ((Item_result)i == STRING_RESULT &&
agg_arg_charsets_for_comparison(cmp_collation, agg, nagg))
return;
if (!(cmp_items[i]=
cmp_item::get_comparator((Item_result)i,
cmp_collation.collation)))

4
sql/sql_string.cc
View File

@ -252,8 +252,8 @@ bool String::copy_aligned(const char *str,uint32 arg_length, uint32 offset,
CHARSET_INFO *cs)
{
/* How many bytes are in incomplete character */
offset= cs->mbmaxlen - offset; /* How many zeros we should prepend */
DBUG_ASSERT(offset && offset != cs->mbmaxlen);
offset= cs->mbminlen - offset; /* How many zeros we should prepend */
DBUG_ASSERT(offset && offset != cs->mbminlen);
uint32 aligned_length= arg_length + offset;
if (alloc(aligned_length))