Improve `R2dbcCustomConversions` creation when using a dialect to ensure registration of driver-simple types

[anuger]

springboot version: 2.4.7
spring-data-r2dbc version: 1.2.9

entity:

public class MessageBody {
    private String msg:
}
public class Message {
    private Integer id;
    private MessageBody body;
}

Repository

public interface MessageRepository extends R2dbcRepository<Message, Integer> {
}

when i call MessageRepository.save(), i get the exception:

reactor.core.Exceptions$ErrorCallbackNotImplemented: org.springframework.dao.InvalidDataAccessApiUsageException: Nested entities are not supported
Caused by: org.springframework.dao.InvalidDataAccessApiUsageException: Nested entities are not supported

If change Message.body to String:

public class Message {
    private Integer id;
    private String body;
}

get exception:

reactor.core.Exceptions$ErrorCallbackNotImplemented: org.springframework.r2dbc.BadSqlGrammarException: executeMany; bad SQL grammar [INSERT INTO message (body) VALUES ($1)]; nested exception is io.r2dbc.postgresql.ExceptionFactory$PostgresqlBadGrammarException: [42804] column "body" is of type json but expression is of type character varying
Caused by: org.springframework.r2dbc.BadSqlGrammarException: executeMany; bad SQL grammar [INSERT INTO message (body) VALUES ($1)]; nested exception is io.r2dbc.postgresql.ExceptionFactory$PostgresqlBadGrammarException: [42804] column "body" is of type json but expression is of type character varying

after add @WritingConverter:

public class MessageBodyWriteConverter implements Converter<MessageBody, Json> {
    @Override
    public Json convert(MessageBody messageBody) {
        return Json.of(new ObjectMapper().writeValueAsString(messageBody));
    }
}

get exception:

reactor.core.Exceptions$ErrorCallbackNotImplemented: org.springframework.dao.DataIntegrityViolationException: executeMany; SQL [INSERT INTO message (body) VALUES ($1)]; null value in column "body" violates not-null constraint; nested exception is io.r2dbc.postgresql.ExceptionFactory$PostgresqlDataIntegrityViolationException: [23502] null value in column "body" violates not-null constraint
Caused by: org.springframework.dao.DataIntegrityViolationException: executeMany; SQL [INSERT INTO message (body) VALUES ($1)]; null value in column "body" violates not-null constraint; nested exception is io.r2dbc.postgresql.ExceptionFactory$PostgresqlDataIntegrityViolationException: [23502] null value in column "body" violates not-null constraint

[mp911de]

If you would like us to spend some time helping you to diagnose the problem, please spend some time describing it and, ideally, providing a minimal sample that reproduces the problem.

Right now it seems that MessageBody is null, however, the entity and converter are correct.

[anuger]

@mp911de 　it's not null

[anuger]

this is my config:

@Configuration
public class R2dbcConfig {

    @Bean
    public R2dbcCustomConversions customConversions() {
        List<Converter<?, ?>> converters = new ArrayList<>();
        converters.add(new MessageBodyReadConverter());
        converters.add(new MessageBodyWriteConverter());
        return new R2dbcCustomConversions(converters);
    }
}

[mp911de]

Remote debugging isn't the most efficient way to track down the cause. While you're already at the debugger, you can trace down the actual write value that is being stored in OutboundRow and the resulting binding in ExtendedQueryPostgresqlStatement.

[anuger]

@mp911de Null is generated here

[mp911de]

Does the same happen if you upgrade to 1.3?

[anuger]

@mp911de I upgraded to 1.3.2, have the same exception

[mp911de]

Without a reproducer, I'm not able to reproduce the issue which makes it impossible to diagnose what causes the issue.

[anuger]

I created a project to demonstrate this problem
MessageServiceTest

[mp911de]

Thanks a lot. The issue happens due to Json not being considered as simple type. I didn't immediately spot that the dialect is missing when constructing R2dbcCustomConversions. R2dbcCustomConversions should be created as follows:

return new R2dbcCustomConversions.of(PostgresDialect.INSTANCE, new MessageBodyReadConverter(), new MessageBodyWriteConverter());

That isn't obvious from the constructor's signature. It makes sense to deprecate the constructor that takes only a collection of converters and point to the of(…) factory method.

Depending on the driver/dialect, we can register additional simple types that allow database-specific functionality.