OptionalRowMapperFactory can cause NullPointerExceptions with custom Row Mappers

[Randgalt]

OptionalRowMapperFactory doesn't change how underlying mappers interpret propagating nulls. So, a common use case will cause NullPointerException. If a SqlQuery returns an Optional single column row, the underlying mapper is called even if the column is null when a custom row mapper is registered for a type.

Example:

Test.java

package test;

import org.jdbi.v3.core.Jdbi;
import org.jdbi.v3.core.config.ConfigRegistry;
import org.jdbi.v3.core.mapper.ColumnMapper;
import org.jdbi.v3.core.mapper.RowMapper;
import org.jdbi.v3.core.mapper.RowMapperFactory;
import org.jdbi.v3.core.mapper.reflect.JdbiConstructor;
import org.jdbi.v3.core.statement.StatementContext;
import org.jdbi.v3.sqlobject.SqlObjectPlugin;
import org.jdbi.v3.sqlobject.customizer.Bind;
import org.jdbi.v3.sqlobject.statement.SqlQuery;
import org.jdbi.v3.sqlobject.statement.SqlUpdate;
import org.testcontainers.containers.PostgreSQLContainer;

import java.lang.reflect.Type;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Optional;

import static java.util.Objects.requireNonNull;

public class Test
{
    public record Value(String value)
    {
        @JdbiConstructor
        public Value
        {
            requireNonNull(value, "value is null");
        }
    }

    public interface Dao
    {
        @SqlQuery("SELECT value FROM foo where key = :key")
        Optional<Value> get(@Bind("key") String key);

        @SqlUpdate("INSERT INTO foo(key, value) VALUES (:key, :value)")
        void insert(@Bind("key") String key, @Bind("value") Optional<Value> value);
    }

    public static class Mapper
            implements RowMapperFactory, RowMapper<Value>
    {
        @Override
        public Optional<RowMapper<?>> build(Type type, ConfigRegistry config)
        {
            if (type.equals(Value.class)) {
                return Optional.of(this);
            }
            return Optional.empty();
        }

        @Override
        public Value map(ResultSet rs, StatementContext ctx)
                throws SQLException
        {
            String value = rs.getString("value");
            return new Value(value);
        }
    }

    public static void main(String[] args)
    {
        PostgreSQLContainer container = new PostgreSQLContainer();
        container.start();

        Jdbi jdbi = Jdbi.create(container.getJdbcUrl(), container.getUsername(), container.getPassword())
                .installPlugin(new SqlObjectPlugin())
                .registerColumnMapper(Value.class, ColumnMapper.getDefaultColumnMapper())
                .registerRowMapper((RowMapperFactory) new Mapper());

        jdbi.useHandle(handle -> handle.execute("CREATE TABLE foo (key VARCHAR NOT NULL PRIMARY KEY, value VARCHAR)"));

        jdbi.useExtension(Dao.class, dao -> dao.insert("1", Optional.empty()));

        // this will throw NPE
        Optional<Value> value = jdbi.withExtension(Dao.class, dao -> dao.get("1"));

        container.stop();
    }
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>foo</groupId>
    <artifactId>jdbi-bug</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>21</maven.compiler.source>
        <maven.compiler.target>21</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.jdbi</groupId>
                <artifactId>jdbi3-bom</artifactId>
                <version>3.45.1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.jdbi</groupId>
            <artifactId>jdbi3-core</artifactId>
        </dependency>

        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>42.7.2</version>
        </dependency>

        <dependency>
            <groupId>org.jdbi</groupId>
            <artifactId>jdbi3-json</artifactId>
        </dependency>

        <dependency>
            <groupId>org.jdbi</groupId>
            <artifactId>jdbi3-sqlobject</artifactId>
        </dependency>

        <dependency>
            <groupId>org.testcontainers</groupId>
            <artifactId>testcontainers</artifactId>
            <version>1.19.4</version>
        </dependency>

        <dependency>
            <groupId>org.testcontainers</groupId>
            <artifactId>postgresql</artifactId>
            <version>1.19.4</version>
        </dependency>
    </dependencies>
</project>

[wendigo]

@hgschmie gentle ping :)