/spring-data-rest-enum-description-npe

Primary LanguageJava

Issue Description

In Spring Data REST 3.2.6.RELEASE, given an enum field annotated with org.springframework.data.rest.core.annotation.Description, in this example, gender

@Entity
@Data
@NoArgsConstructor
public class User {

    @Id
    Long id;

    @Description("User name")
    String name;

    @Description("User gender, MALE or FEMALE")
    Gender gender;
}

when get JSON schema, then NullPointerException.

Reproduce Issue Steps

  1. Run this Spring Boot application on localhost:8080
  2. Visit http://localhost:8080/profile/users with header "Accept: application/schema+json", for example 
    curl --request GET 'http://localhost:8080/profile/users' \
     --header 'Accept: application/schema+json' \
     --include
  3. Get HTTP 500 response
  4. Application log shows a NullPointerException thrown at PersistentEntityToJsonSchemaConverter.java:489 org.springframework.data.rest.webmvc.json.PersistentEntityToJsonSchemaConverter.JacksonProperty.getSchemaProperty(BeanPropertyDefinition, TypeInformation<?>, ResourceDescription, InternalMessageResolver)

Preliminary Investigation

At PersistentEntityToJsonSchemaConverter.java:489 description.getDefaultMessage().equals(resolvedDescription), the implementation class AnnotationBasedResourceDescription doesn't implement method getDefaultMessage() and its super implementation ResolvableResourceDescriptionSupport.getDefaultMessage() return null.

Workaround

Put the description to rest-messages.properties, see https://docs.spring.io/spring-data/rest/docs/current/reference/html/#metadata.alps.descriptions

Why use @Description which is not mentioned in Spring Data REST reference document?

I might forget to update the description if put to an external file rest-messages.properties. And spring-data-rest-tests does demonstrates its usage. Actually I found this annotation @Description from @RepositoryRestResource.itemResourceDescription. Just try and the description is shown in ALPS document.