@TypeAlias used in sub objects only works for save not load

[sebastienvermeille]

based on: https://gitter.im/spring-projects/spring-data?at=604878ed22a5ce4a91464a41

Assuming I have the following structure:

@RedisHash("Animal")
@TypeAlias("Cat")
public class Cat extends Animal {}

@RedisHash("Animal")
@TypeAlias("Dog")
public class Dog extends Animal {}

@RedisHash("Animal")
@TypeAlias("Animal")
public abstract class Animal {
  @Id
  @Indexed
  @NonNull
  protected String id;
}

class AnimalWrapper {
   @Id
    private String id;
     private Animal animal;
}

What is persisted in redis:

keys list

127.0.0.1:6379> keys *
1) "Animal"
2) "Animal:animal.id:c2873cc8-6dba-4fdc-9143-f642f6815f3d"
3) "Animal:dog-id:idx"
4) "Animal:cat-id:idx"
5) "Animal:dog-id"
6) "Animal:animal.id:f86eaa67-4910-4b66-afbe-f6b02576fa53"
7) "Animal:cat-id"

inside of Animal:dog-id

127.0.0.1:6379> HGETALL Animal:dog-id
 1) "_class"
 2) "Animal"
 3) "id"
 4) "dog-id"
 5) "animal._class"
 6) "Dog"
 7) "animal.postmanCounter"
 8) "2"
 9) "animal.id"
10) "f86eaa67-4910-4b66-afbe-f6b02576fa53"

Everything looks ok.
There is no issue to persist the objects I can see them gracefully persisted into redis with the correct TypeAlias.

The problem is when I try to retrieve the data.

1. retrieving them right after persisting them -> fine no problem (cf: see the unit test in the attached repository)
2. retrieving them without persisting them before (already persisted in redis db) ->

java.lang.InstantiationError: com.example.springdataredisexample.models.Animal

	at com.example.springdataredisexample.models.Animal_Instantiator_csbm6u.newInstance(Unknown Source)
	at org.springframework.data.mapping.model.ClassGeneratingEntityInstantiator$EntityInstantiatorAdapter.createInstance(ClassGeneratingEntityInstantiator.java:238)
	at org.springframework.data.mapping.model.ClassGeneratingEntityInstantiator.createInstance(ClassGeneratingEntityInstantiator.java:87)
	at org.springframework.data.redis.core.convert.MappingRedisConverter.doReadInternal(MappingRedisConverter.java:234)
	at org.springframework.data.redis.core.convert.MappingRedisConverter.readInternal(MappingRedisConverter.java:192)
	at org.springframework.data.redis.core.convert.MappingRedisConverter.readProperty(MappingRedisConverter.java:299)
	....

How to reproduce:

1. clone the following repo: https://github.com/sebastienvermeille/bugreport-spring-data-redis
2. deploy a redis server (i.e: docker run --name some-redis -p 6379:6379 -d redis)
3. execute only the unit test: findAllShouldReturn2AnimalsWhenSavedACatAndADog this will persist 2 animals
4. stop the spring app
5. execute only the unit test: findAllShouldAlsoReturnAnimalsWhenTheyExistAlreadyInDb
6. check in redis you should still have the previous animals persisted
7. but the unit test fails as it generate an exception on invoking findAll()

I stay available in case I could eventually help.

[mp911de]

The problem here is that our RedisKeyValueAdapter is called with the keyspace only. The type hint from the repository is lost as the adapter interface doesn't accept the desired entity type.

Going further, the type hits are unknown because Dog and Cat are not registered in RedisMappingContext (RedisMappingContext.setInitialEntitySet(…)).