revoking a role for user still leave the privilege of the role intact for that user

[unconsolable]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

# root
mysql> create user u1;
Query OK, 0 rows affected (0.03 sec)

mysql> create role r1;
Query OK, 0 rows affected (0.03 sec)

mysql> create table t1 (c1 int);
Query OK, 0 rows affected (0.09 sec)

mysql> grant select on t1 to r1;
Query OK, 0 rows affected (0.03 sec)

mysql> grant r1 to u1;
Query OK, 0 rows affected (0.02 sec)

# u1
mysql> set role all;
Query OK, 0 rows affected (0.01 sec)

mysql> select * from test.t1;
Empty set (0.00 sec)

# root
mysql> revoke r1 from u1;
Query OK, 0 rows affected (0.03 sec)

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

# u1
mysql> select * from test.t1;
ERROR 1142 (42000): SELECT command denied to user 'u1'@'172.17.0.1' for table 't1'

3. What did you see instead (Required)

mysql> select * from test.t1;
Empty set (0.00 sec)

4. What is your TiDB version? (Required)

master fb01f00

[lcwangchao]

/assign

[github-actions]

Please check whether the issue should be labeled with 'affects-x.y' or 'fixes-x.y.z', and then remove 'needs-more-info' label.