MySQL Bugs: #33452: Primary difference between capital and small letters U and O

Bug #33452	Primary difference between capital and small letters U and O
Submitted:	21 Dec 2007 10:23	Modified:	6 Feb 2008 18:59
Reporter:	Alexander Barkov
Status:	Closed
Category:	Server: Charsets	Severity:	S3 (Non-critical)
Version:	6.0	OS:	Any
Assigned to:	Alexander Barkov	Target Version:
Triage:	D4 (Minor) / R3 (Medium) / E3 (Medium)

Description:
"O" and "o" have different weights on the primary level.
The same problem happens with "U" and "u".

This is perfectly seen on this chart:

http://www.collation-charts.org/mysql60/mysql604.latin2_czech_cs.html

Capital letters O and U are on separate lines from their
lower case counterparts, which means primary difference.

How to repeat:
Correct result (no primary difference):
=======================================

mysql> select hex(weight_string(_latin2'a' collate latin2_czech_cs level 1));
+----------------------------------------------------------------+
| hex(weight_string(_latin2'a' collate latin2_czech_cs level 1)) |
+----------------------------------------------------------------+
| 8201                                                           |
+----------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> select hex(weight_string(_latin2'A' collate latin2_czech_cs level 1));
+----------------------------------------------------------------+
| hex(weight_string(_latin2'A' collate latin2_czech_cs level 1)) |
+----------------------------------------------------------------+
| 8201                                                           |
+----------------------------------------------------------------+
1 row in set (0.00 sec)

Wrong results ("O" is primary greater than "o", the same for "U" and "u")
=========================================================================

mysql> select hex(weight_string(_latin2'O' collate latin2_czech_cs level 1));
+----------------------------------------------------------------+
| hex(weight_string(_latin2'O' collate latin2_czech_cs level 1)) |
+----------------------------------------------------------------+
| 9301                                                           |
+----------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> select hex(weight_string(_latin2'o' collate latin2_czech_cs level 1));
+----------------------------------------------------------------+
| hex(weight_string(_latin2'o' collate latin2_czech_cs level 1)) |
+----------------------------------------------------------------+
| 9201                                                           |
+----------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> select hex(weight_string(_latin2'u' collate latin2_czech_cs level 1));
+----------------------------------------------------------------+
| hex(weight_string(_latin2'u' collate latin2_czech_cs level 1)) |
+----------------------------------------------------------------+
| 9B01                                                           |
+----------------------------------------------------------------+
1 row in set (0.01 sec)

mysql> select hex(weight_string(_latin2'U' collate latin2_czech_cs level 1));
+----------------------------------------------------------------+
| hex(weight_string(_latin2'U' collate latin2_czech_cs level 1)) |
+----------------------------------------------------------------+
| 9C01                                                           |
+----------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> 

Suggested fix:
Make "O" primary equal to "o",
make "U" primary equal to "u".

Thank you for the bug report.

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/40836

ChangeSet@1.2706, 2008-01-10 15:51:02+04:00, bar@mysql.com +3 -0
  Bug#33452 Primary difference between capital and small letters U and O
  Problem: wrong primary weight for all variants of capital letters "U" and "O".
  Fix: changing primary weights for the letters "U" and "O"
  to be equal to their small counterparts.

Ok to push.

Pushed into rpl team tree, currently marked as 6.0.4.

Pushed into 6.0.5-alpha

Noted in 6.0.5 changelog.

For the latin2_czech_cs collation, the primary weights for all
variants of capital letters U and O were incorrect (were not equal to
the corresponding small letters).