Equivalent view extraction retags UNION ALL integer payload as ENUM text

[123lpygithub]

Under semantic-equivalent rewriting, the source and mutated queries are logically equivalent, but produce different results on PolarDB-X.

version:5.4.19-SNAPSHOT

How to repeat:

DROP DATABASE IF EXISTS vect_submit_c1;
CREATE DATABASE vect_submit_c1;
USE vect_submit_c1;

CREATE TABLE t2 (
  c10 ENUM('value1','value2','value3')
);

INSERT INTO t2 VALUES ('value3');

-- View SQL
CREATE VIEW v AS
SELECT 1 AS dummy;

-- Source Original SQL
SELECT c10 AS col1
FROM t2
UNION ALL
SELECT 3 AS col1;

-- Mutated SQL
SELECT c10 AS col1
FROM t2 JOIN v
UNION ALL
SELECT 3 AS col1;

Observed result - Query A (original):

col1
value3
3

Observed result - Query B (mutated):

col1
value3
value3