camelCase properties not mapped at deserialization time

[Djaytan]

Hello,

When I try to deserialize the following YAML file:

hostname: 'example.com'
port: 1234
isSslEnabled: true

My test fail because of this error message:

org.opentest4j.AssertionFailedError: 
Expecting value to be true but was false
Expected :true
Actual   :false

Whereas I can observe that in debug mode:

The unit test:

      // Given
      String yamlFileName = "whenDeserializing_withValidValues.yml";
      Path yamlFile =
          ResourcesHelper.getResourcePath(HostValidatingPropertiesTest.class, yamlFileName);

      // When
      Optional<HostValidatingProperties> optionalHostValidatingProperties =
          YamlDeserializer.deserialize(yamlFile, HostValidatingProperties.class);

      // Then
      assertThat(optionalHostValidatingProperties).isPresent();

      HostValidatingProperties hostValidatingProperties = optionalHostValidatingProperties.get();

      assertAll(() -> assertThat(hostValidatingProperties.getHostname()).isEqualTo("example.com"),
          () -> assertThat(hostValidatingProperties.getPort()).isEqualTo(1234),
          () -> assertThat(hostValidatingProperties.isSslEnabled()).isTrue());

And the YamlDeserializer class:

/**
 * YAML deserializer for testing purposes.
 */
public final class YamlDeserializer {

  private YamlDeserializer() {
    // Static class
  }

  /**
   * Deserializes the given YAML file into the specified type.
   *
   * @param yamlFile The YAML content to deserialize.
   * @param type The expected type of the YAML content.
   * @return The deserialized value if present and of valid type.
   * @param <T> The expected type to be obtained from deserialization.
   */
  @SneakyThrows
  public static <T> @NonNull Optional<T> deserialize(@NonNull Path yamlFile,
      @NonNull Class<T> type) {
    ConfigurationNode rootNode = buildYamlConfigurationNode(yamlFile);
    return Optional.ofNullable(rootNode.get(type));
  }

  @SneakyThrows
  private static @NonNull ConfigurationNode buildYamlConfigurationNode(@NonNull Path yamlFile) {
    return YamlConfigurationLoader.builder().path(yamlFile).build().load();
  }
}

Do you have any idea about why finally the deserialized boolean value has been converted to false? Is it a bug?

Thanks a lot for your time.

[Djaytan]

Same issue with Hocon config file with configurate-hocon module:

{
  hostname: "example.com",
  port: 1234,
  isSslEnabled: true
}

[zml2008]

This sounds like it's some issue with HostValidatingProperties, do you have that class handy?

[Djaytan]

I suspect that the behavior come from HostValidatingProperties effectively:

/**
 * Represents an annotated Java Beans version of an {@link HostProperties}.
 */
@ConfigSerializable
@Data
@EqualsAndHashCode(callSuper = true)
@ToString(callSuper = true)
public final class HostValidatingProperties extends ValidatingConvertibleProperties<HostProperties> {

  /**
   * An hostname cannot exceed 255 characters as per the DNS standard specification.
   */
  @NotBlank
  @Size(max = 255)
  private String hostname;

  /**
   * A port cannot exceed 65535, which is the maximum value allowed by the Transport Control
   * Protocol (TCP) and User Datagram Protocol (UDP) standards.
   */
  @Max(65535)
  @PositiveOrZero
  private int port;
  private boolean isSslEnabled;

  @Override
  protected @NonNull HostProperties convertValidated() {
    return HostProperties.of(hostname, port, isSslEnabled);
  }
}

And the parent class ValidatingConvertibleProperties:

/**
 * Represents a convertible data structure after validation which provides a way to convert it to
 * its final form.
 *
 * <p>This approach allows for decoupling the validation and the final data structure creation.
 *
 * @param <T> The type of the final data structure.
 */
@EqualsAndHashCode
@ToString
public abstract class ValidatingConvertibleProperties<T> {

  private boolean isValidated = false;

  /**
   * Marks the properties as validated.
   */
  public void markAsValidated() {
    this.isValidated = true;
  }

  /**
   * Converts the properties to the "ready to use" data structure version.
   *
   * @return The "ready to use" data structure version.
   * @throws IllegalStateException if properties have not been validated before the conversion.
   */
  public T convert() {
    if (!isValidated) {
      throw new IllegalStateException("Properties must be validated before being converted");
    }
    return convertValidated();
  }

  /**
   * Converts the data from the current instance of the class inheriting this.
   *
   * <p><i>Note: This method must be called only after the data structure validation.
   *
   * @return The converted final data structure.
   */
  @NonNull
  protected abstract T convertValidated();
}

I suspect a conflict with the boolean value isValidated: it is supposed to remain false.

[Djaytan]

I have updated the corresponding test:

assertAll(() -> assertThat(hostValidatingProperties.getHostname()).isEqualTo("example.com"),
          () -> assertThat(hostValidatingProperties.getPort()).isEqualTo(1234),
          () -> assertThat(hostValidatingProperties.isSslEnabled()).isTrue(),
          () -> assertThat(hostValidatingProperties.isValidated()).isFalse());

And no problem about the isValidated one: the value is false as expected.

[zml2008]

Ah, that makes sense -- migrating to a discussion because this is not a bug. Configurate's object mapper by default applies normalization to field names, converting camelCase to kebab-case, so the expected field name would be is-ssl-enabled. You can override this for that specific field with the @setting annotation, or change the naming scheme on the object mapper passed to the type serializer collection in the options used by your loader.

[Djaytan]

For the record:
I updated the YamlDeserializer class with the following code:

@SneakyThrows
  private static @NonNull ConfigurationNode buildYamlConfigurationNode(@NonNull Path yamlFile) {
    ObjectMapper.Factory customFactory =
        ObjectMapper.factoryBuilder().defaultNamingScheme(NamingSchemes.CAMEL_CASE).build();

    return YamlConfigurationLoader.builder().path(yamlFile)
        .defaultOptions(
            opts -> opts.serializers(builder -> builder.registerAnnotatedObjects(customFactory)))
        .build().load();
  }

And now tests are green 😄

Explanations were given on the following documentation: https://github.com/SpongePowered/Configurate/wiki/Object-Mapper

Thanks a lot zml for your help!