buildUpdateLists has some confusion with updatable-table and non-updatable table (eg: subquery with alias)

[AilinKid]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

mysql> create table t(a int default -1, c int as (a+10) stored);
Query OK, 0 rows affected (0.04 sec)

mysql> insert into t(a) values(1);
Query OK, 1 row affected (0.00 sec)

mysql> update test.t, (select 1 as b) as t set test.t.a=default;
Query OK, 1 row affected (0.02 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from t;
+------+------+
| a    | c    |
+------+------+
|   -1 |   11 |
+------+------+
1 row in set (0.00 sec)

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

new result of generated column stored should be 9

3. What did you see instead (Required)

11

4. What is your TiDB version? (Required)

master

some details: it is caused by the table name resolver confusion in build update (exactly in b.buildUpdateLists)

[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.