ReferenceObjectCache.makeSoftCache() makes lazily loaded foreign collections sometimes return null

[dkapaev]

Steps to reproduce:

1. In DBHelper I created DAOs for all entities like this

   public MyEntityDao getMyEntityDao() {
       try {
           if (mMyEntityDao == null) {
               mMyEntityDao = new MyEntityDao(getConnectionSource(), MyEntity.class);
               mMyEntityDao.setObjectCache(ReferenceObjectCache.makeSoftCache());
           }
       } catch (SQLException e) {
           e.printStackTrace();
       }
       return mMyEntityDao;
   }

2. MyEntity class:

   @DatabaseTable
   public class MyEntity {
   ...
   @ForeignCollectionField(eager = false)
   private Collection<MyEntityValue> myEntityValues;
   
   public Collection<MyEntityValue> getMyEntityValues() {
       return myEntityValues;
   }
   ...
   }

3. I make a network call, cascade delete all old entities and insert new ones. Without cache enabled, Collection<MyEntityValue> myEntityValues was an empty/non-empty LazyForeignCollection. With cache enabled, it is sometimes NULL and causing NPEs in parts of code that previously worked.