create index with multi-layer virtual generated column return wrong result

[wjhuang2016]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

mysql> create table t(a int, b tinyint as(a+1), c int as(b+1));
Query OK, 0 rows affected (0.01 sec)

mysql> set sql_mode="";
Query OK, 0 rows affected (0.00 sec)

mysql> insert into t(a) values(2000);
Query OK, 1 row affected, 1 warning (0.01 sec)

mysql> create index idx on t(c);
Query OK, 0 rows affected (0.02 sec)

mysql> select c from t;
+------+
| c    |
+------+
| 2002 |
+------+
1 row in set (0.00 sec)

mysql> select * from t;
+------+------+------+
| a    | b    | c    |
+------+------+------+
| 2000 |  127 |  128 |
+------+------+------+
1 row in set, 1 warning (0.00 sec)

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

mysql> select c from t;
+------+
| c    |
+------+
| 128 |
+------+
1 row in set (0.00 sec)

3. What did you see instead (Required)

2002

4. Affected version (Required)

master

5. Root Cause Analysis