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Mybatis 3.5.5 ResultMap Bug

See original GitHub issue

MyBatis version

3.5.5

Database vendor and version

Oracle 12C

Test case or example project

I’ve a test case which is working fine on Mybatis version 3.5.4 Here is my XML mapper

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.mycom.query.test">
    <resultMap id="headerResultMap" type="com.mycom.query.test.TestHeader">
        <constructor>
            <idArg column="H_ID" javaType="_int" name="id"/>
        </constructor>
        <result property="field1" column="H_FIELD1"/>
        <result property="field2" column="H_FIELD2"/>
        <result property="field3" column="H_FIELD3"/>
    </resultMap>

    <resultMap id="detailResultMap" type="com.mycom.query.test.TestDetail">
        <constructor>
            <idArg column="D_ID" javaType="_int" name="id"/>
            <idArg column="D_SEQ" javaType="_int" name="seq"/>
        </constructor>
        <result property="field1" column="D_FIELD1"/>
        <result property="field2" column="D_FIELD2"/>
        <result property="field3" column="D_FIELD3"/>
    </resultMap>

    <resultMap id="testResultMap" type="com.mycom.query.test.TestOrder">
        <constructor>
            <idArg resultMap="headerResultMap" javaType="com.mycom.query.test.TestHeader"/>
        </constructor>
        <collection property="details" ofType="com.mycom.query.test.TestDetail" resultMap="detailResultMap"/>
    </resultMap>

    <select id="find" resultMap="testResultMap">
        SELECT
            *
        FROM (
            SELECT
                1 AS H_ID,
                'H_FIELD1' AS H_FIELD1,
                'H_FIELD2' AS H_FIELD2,
                'H_FIELD3' AS H_FIELD3
            FROM
                DUAL
        ) H
        LEFT JOIN (
            SELECT
                1 AS D_ID,
                1 AS D_SEQ,
                'D_FIELD1' AS D_FIELD1,
                'D_FIELD2' AS D_FIELD2,
                'D_FIELD3' AS D_FIELD3
            FROM
                DUAL
            UNION ALL
            SELECT
                1 AS D_ID,
                2 AS D_SEQ,
                'D_FIELD4' AS D_FIELD1,
                'D_FIELD5' AS D_FIELD2,
                'D_FIELD6' AS D_FIELD3
            FROM
                DUAL
            UNION ALL
            SELECT
                1 AS D_ID,
                3 AS D_SEQ,
                'D_FIELD7' AS D_FIELD1,
                'D_FIELD8' AS D_FIELD2,
                'D_FIELD9' AS D_FIELD3
            FROM
                DUAL
        ) D ON H.H_ID=D.D_ID
    </select>
</mapper>

The result will produce one to many rows and map to my model

import java.util.List;

public class TestOrder {

    private final TestHeader header;

    private List<TestDetail> details;

    public TestOrder(TestHeader header) {
        this.header = header;
    }

    public TestHeader getHeader() {
        return header;
    }

    public List<TestDetail> getDetails() {
        return details;
    }

    public void setDetails(List<TestDetail> details) {
        this.details = details;
    }

    @Override
    public String toString() {
        return getClass().getName() + "[header=" + header + ", details=" + details + ']';
    }
}

Steps to reproduce

Call using selectOne method, and I’m expect it will return 1 single object which is TestOrder. However, Mybatis 3.5.5 failed with message Expected one result (or null) to be returned by selectOne(), but found: 3