MySQL Bugs: #34552: REGEXP fails with multi-byte characters

Bug #34552	REGEXP fails with multi-byte characters
Submitted:	14 Feb 2008 15:57	Modified:	14 Feb 2008 18:10
Reporter:	Andreas Götz	Email Updates:
Status:	Duplicate	Impact on me:	None
Category:	MySQL Server: Charsets	Severity:	S2 (Serious)
Version:	5.0.54	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
I had already reported in bug 34473 that RLIKE files on multi-byte data. Investigation showed that this is due to the REGEXP engine working on byte values (doh).

New issue found is that regexp engine- independently from byte values- seems to treat characters and classes differently.

How to repeat:
SELECT 'Ø' REGEXP 'Ö';
-> result 0

SELECT 'Ø' REGEXP '[Ö]';
-> result 1

Expected result:
If Ø matches Ö at all for a given collation (even if handled byte-wise), the result should at least be consistent.

Suggested fix:
Upgrade REGEXP library- the current implementation is not worthy of MySQLs other unicode capabilities.

I've just realized that my argument is not soud. Of cause (byte-wise) 'ab' is a different pattern than '[ab]'.
Suggested fix is still the same though ;)

As far as I understand, you agree that this is not a separate bug but a consequence of REGEX working byte-wise. I'll mark it as a duplicate of bug#34473 then.