java.lang.NullPointerException when using ResourceProcessor<RepositoryLinksResource> and SpringSecurity [DATAREST-702]

Manuel Sousa opened DATAREST-702 and commented

I have a custom controller which implements ResourceProcessor<RepositoryLinksResource> in order to populate the root response as in: http://stackoverflow.com/questions/25783487/custom-response-for-root-request-int-the-spring-rest-hateoas-with-both-repositor/26118405#26118405

If one of the controller methods is annotated with springsecurity Pre/PostAuthorize I get a null pointer exception when booting the application:
...
Caused by: java.lang.NullPointerException
at org.springframework.data.rest.webmvc.ResourceProcessorHandlerMethodReturnValueHandler.<init>(ResourceProcessorHandlerMethodReturnValueHandler.java:89)
at org.springframework.data.rest.webmvc.ResourceProcessorInvokingHandlerAdapter.afterPropertiesSet(ResourceProcessorInvokingHandlerAdapter.java:75)
at org.springframework.data.rest.webmvc.RepositoryRestHandlerAdapter.afterPropertiesSet(RepositoryRestHandlerAdapter.java:60)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574)
...

I think the issue lies in the processor being Proxy$... instead of the ControllerClass.
Moving the method to another class, for instance the DAO fixes the issue as an workaround.

Not sure if this is a bug, a design choice or if i'm missing something.

@RestController
@ExposesResourceFor(Device.class)
@RequestMapping(value = "/devices", produces = "application/hal+json")
public class DeviceController implements ResourceProcessor<RepositoryLinksResource> {
...
    @RequestMapping(path = "/{id}")
    @PreAuthorize("isAuthenticated()")
    public Resource<Device> getDevice(@PathVariable("id") String id){
    ...
    }

    public RepositoryLinksResource process(RepositoryLinksResource resource) {
        resource.add(ControllerLinkBuilder.linkTo(DeviceController.class).withRel("devices"));
        return resource;
    }
}

Removing the @PreAuthorize or moving it to the dao is enough for it to work as expected

Affects: 2.4 GA (Gosling)

Referenced from: commits https://github.com/spring-projects/spring-data-rest/commit/e08dff846e1589dcae147be6714c0ace97620795