select date '2020-02--1' fails

[SunRunAway]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

mysql> select date '2020-02--1';
ERROR 1292 (22007): Incorrect datetime value: '2020-02--1'
mysql> select convert('2020-02--1' , date);
+------------------------------+
| convert('2020-02--1' , date) |
+------------------------------+
| NULL                         |
+------------------------------+
1 row in set, 1 warning (0.00 sec)

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

mysql> select date '2020-02--1';
+-------------------+
| date '2020-02--1' |
+-------------------+
| 2020-02-01        |
+-------------------+
1 row in set (0.00 sec)

mysql> select convert('2020-02--1' , date);
+------------------------------+
| convert('2020-02--1' , date) |
+------------------------------+
| 2020-02-01                   |
+------------------------------+
1 row in set (0.00 sec)

3. Affected version (Required)

master(e0ec3e3)

4. Root Cause Analysis