Custom repository implementation is not exposed as REST endpoint after upgrade from 4.x to 5.x

[agebhar1]

Given a simple REST exposed repository with a custom fragment

@Entity
class Item {

    @Id
    @GeneratedValue(strategy = GenerationType.UUID)
    var id: UUID? = null

    lateinit var value: String

}

interface SearchRepository {
    fun fragment(): Iterable<Item>
}

class SearchRepositoryImpl : SearchRepository {
    override fun fragment(): Iterable<Item> {
        return emptyList()
    }
}

@RepositoryRestResource
interface EntityRepository : Repository<Item, UUID>, SearchRepository {
    fun findAll(): Iterable<Item>
}

With Spring Boot 3 which uses Spring Data REST 4 the following response is returned if request the (generated) /{repository}/search` endpoint:

{
  "_links" : {
    "fragment" : {
      "href" : "https://example.com/items/search/fragment"
    },
    "self" : {
      "href" : "https://example.com/items/search"
    }
  }
}

But after update to Spring Boot 4 which uses Spring Data REST 5 the endpoint can not be found anymore. Also the main repository endpoint /{repository} lost the search link:

{
  "_embedded" : {
    "items" : [ ]
  },
  "_links" : {
    "self" : {
      "href" : "https://example.com/items"
    },
    "profile" : {
      "href" : "https://example.com/profile/items"
    }
  }
}

Before update:

{
   "_embedded" : {
     "items" : [ ]
   },
   "_links" : {
     "self" : {
       "href" : "https://example.com/items"
     },
     "profile" : {
       "href" : "https://example.com/profile/items"
     },
     "search" : {
       "href" : "https://example.com/items/search"
     }
   }
 }

A minimal project with test(s) can be found at https://github.com/agebhar1/gh-spring-data-rest-repository-fragment with a branch for Spring Boot 3 w/ Spring Data REST 4 and Spring Boot 4 w/ Spring Data REST 5.

[mp911de]

Thanks for the report. With the major version, we refined query method detection by considering custom implementations. Query methods are methods that are either backed by a derived or by a declared query whereas a method that uses an implementation fragments is not considered a query method.

@odrotbohm do you have further thoughts on this topic?

[agebhar1]

Thanks @mp911de for your feedback. I started a debugging session and provide my results:

w/ Spring Data REST 4.x uses Spring Data Commons 3.x

.
DefaultQueryMethods is created a first time within the flow with no methods.
.

.
DefaultQueryMethods is created a second time within the flow but with methods.
.

.
fragment search method is added to resource mappings.
.

w/ Spring Data REST 5.x uses Spring Data Commons 4.x

.
DefaultQueryMethods is created a first (and only) time within the flow with no methods.
.

.
Nothing is added to resource mappings.
.

[odrotbohm]

@mp911de – If query methods included fragment-backed methods before, for which methods did we return true from isCustomMethod(…) then?

[mp911de]

Previously, we did not consider fragment implementations. Because of absent metadata we figured that thers is no class implementing the method so we figured that must be a query method. TL;DR: It worked because of a bug.

[agebhar1]

@mp911de when using @Query(...) without an implementing class it's exposed but now I'm not able to handle the custom logic. Is there any annotation right now to mark the method to be included?