v4.0.0rc2 - alter user with hashed password string failed

[AilinKid]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

MySQL [(none)]> create user test3@'%' IDENTIFIED WITH 'mysql_native_password' AS '*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9';
Query OK, 0 rows affected (0.04 sec)

MySQL [(none)]> select user ,host,authentication_string from mysql.user;
+-------+------+-------------------------------------------+
| user  | host | authentication_string                     |
+-------+------+-------------------------------------------+
| root  | %    |                                           |
| test  | %    | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
| test3 | %    | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
+-------+------+-------------------------------------------+
3 rows in set (0.02 sec)

MySQL [(none)]> alter user test3@'%' IDENTIFIED WITH 'mysql_native_password' AS '*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9';
Query OK, 0 rows affected (0.04 sec)

MySQL [(none)]> select user ,host,authentication_string from mysql.user;
+-------+------+-------------------------------------------+
| user  | host | authentication_string                     |
+-------+------+-------------------------------------------+
| root  | %    |                                           |
| test  | %    | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
| test3 | %    | *8E33A6D2D844B026DB599F1BC6F1A2B8665A1CAE |
+-------+------+-------------------------------------------+
3 rows in set (0.00 sec)

select PASSWORD('*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9');
+-------------------------------------------------------+
| PASSWORD('*6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9') |
+-------------------------------------------------------+
| *8E33A6D2D844B026DB599F1BC6F1A2B8665A1CAE             |
+-------------------------------------------------------+
1 row in set, 1 warning (0.01 sec)

2. What did you expect to see? (Required)

auth_string should be the same.

3. What did you see instead (Required)

auto_string(hash string be encoded again)

4. Affected version (Required)

4.0.0 rc2

5. Root Cause Analysis

• alter user without juge the hash string and encode again