MySQL Bugs: #104642: gbk field converts to gb18030 failed

Bug #104642	gbk field converts to gb18030 failed
Submitted:	17 Aug 2021 8:52	Modified:	17 Aug 2021 12:10
Reporter:	GONGTUI FU	Email Updates:
Status:	Not a Bug	Impact on me:	None
Category:	MySQL Server	Severity:	S3 (Non-critical)
Version:	8.0.25	OS:	Any
Assigned to:		CPU Architecture:	Any
Tags:	gbk gb18030

Description:
Hi:
  A table named t has default character set gbk and a column id varchar(100).
  An error occurred when Inserting a hex-value and converting to gb18030.

How to repeat:
1. 
mysql> create table t(id varchar(100)) charset=gbk;
Query OK, 0 rows affected (0.01 sec)

2.  
mysql> insert into t select 0xACBE;
Query OK, 1 row affected (0.01 sec)

3. 
mysql> alter table t  convert to character set gb18030;
ERROR 1366 (HY000): Incorrect string value: '\xAC\xBE' for column 'id' at row 1

Suggested fix:
0xACBE is not a valid gbk character, so converting would fail.
Should it fail to insert 0XACBE?

Hi Mr. FU,

Thank you for your bug report.

MySQL does check whether hex representation of the string is valid and permitted for all character sets.

That 2-byte combo does not conform to the rules of the GBK character set.

Hence, try to insert it with actual string values.

Not a bug.