[FIXED] Id to Entity conversion is not working in Spring Boot 2.2.8 and higher

Issue

I tried to upgrade the Spring Boot version for my application and found a difference in behavior. When switching from 2.2.7 to 2.2.8 (and higher), the conversion from identifier to database entity stops working.

Application:

@SpringBootApplication
public class DomainClassConverterTestApplication {

    public static void main(String[] args) {
        SpringApplication.run(DomainClassConverterTestApplication.class, args);
    }

    @Bean
    CommandLineRunner initialize(ModelRepository modelRepository) {
        return args -> {
            Stream.of("Model 1", "Model 2", "Model X").forEach(name -> {
                Model model = new Model();
                model.setName(name);
                modelRepository.save(model);
            });
        };
    }
}

Controller:

@RestController
public class ModelController {
    private final ModelRepository repository;

    public ModelController(ModelRepository repository) {
        this.repository = repository;
    }

    @GetMapping("/models/{id}")
    public Model getModel(@PathVariable("id") Model model) {
        return model;
    }

    @GetMapping("/models")
    public Page<Model> findAllModels(Pageable pageable) {
        return repository.findAll(pageable);
    }
}

Model:

@Entity
public class Model {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;
    private String name;

    public Model() {}

    public long getId() { return id; }

    public void setId(long id) { this.id = id; }

    public String getName() { return name; }

    public void setName(String name) { this.name = name; }

    @Override
    public String toString() { return "Model{id=" + id + ", name='" + name + "'}"; }
}

After investigation of this problem, I discovered that the root cause of this is in the DomainClassConverter class. I understand that the problem lies in the setApplicationContext method. The method uses lazy initialization, and it adds converters to СonversionService, but only after the first use. But this event never occurs because the converter is not registered in СonversionService. Here is the method:

public void setApplicationContext(ApplicationContext context) {

    this.repositories = Lazy.of(() -> {

        Repositories repositories = new Repositories(context);

        this.toEntityConverter = Optional.of(new ToEntityConverter(repositories, conversionService));
        this.toEntityConverter.ifPresent(it -> conversionService.addConverter(it));

        this.toIdConverter = Optional.of(new ToIdConverter(repositories, conversionService));
        this.toIdConverter.ifPresent(it -> conversionService.addConverter(it));

        return repositories;
    });
}

Solution

It is a bug DATACMNS-1743 and was fixed in 2.2.8, 2.3.2, and higher.

Answered By - Mikhail Vaysman