fixGH-215): Cannot query set of enums within select clause

[igdianov]

Fixes #215

This PR fixes runtime error when the following query is executed using nested search criteria on selection field with EQ, NE, IN, NIN predicates:

{
  Humans {
    select {
      name
      friends(where: {appearsIn: {EQ: THE_FORCE_AWAKENS}}) {
        name
      }
    }
  }
}

Also, because of GH-216 fix, there is no longer need to use GraphQLJpaOneToManyDataFetcher for many-to-many associations. It has been removed for good. As a result, there will be improved query performance without N+1 queries generated for many-to-many associations attributes with where search criteria, i.e the above GraphQL query will generate JPQL query:

select distinct human 
  from Human as human left join fetch human.friends as generatedAlias0 
  where :param0 member of generatedAlias0.appearsIn 
  order by human.id asc

followed by SQL:

Hibernate: 
    select
        human0_.id as id2_0_0_,
        character2_.id as id2_0_1_,
        human0_.name as name3_0_0_,
        human0_.favorite_droid_id as favorite6_0_0_,
        human0_.gender_code_id as gender_c7_0_0_,
        human0_.homePlanet as homePlan4_0_0_,
        character2_.name as name3_0_1_,
        character2_.primary_function as primary_5_0_1_,
        character2_.favorite_droid_id as favorite6_0_1_,
        character2_.gender_code_id as gender_c7_0_1_,
        character2_.homePlanet as homePlan4_0_1_,
        character2_.DTYPE as DTYPE1_0_1_,
        friends1_.source_id as source_i1_2_0__,
        friends1_.friend_id as friend_i2_2_0__ 
    from
        Character human0_ 
    left outer join
        character_friends friends1_ 
            on human0_.id=friends1_.source_id 
    left outer join
        Character character2_ 
            on friends1_.friend_id=character2_.id 
    where
        human0_.DTYPE='Human' 
        and (
            ? in (
                select
                    appearsin3_.appearsIn 
                from
                    Character_appearsIn appearsin3_ 
                where
                    character2_.id=appearsin3_.Character_id
            )
        ) 
    order by
        human0_.id asc,
        character2_.name asc

[codecov]

Codecov Report

Merging #218 into master will increase coverage by 0.03%.
The diff coverage is 80%.

@@             Coverage Diff              @@
##             master     #218      +/-   ##
============================================
+ Coverage     73.65%   73.69%   +0.03%     
+ Complexity      862      850      -12     
============================================
  Files            50       49       -1     
  Lines          3727     3668      -59     
  Branches        624      613      -11     
============================================
- Hits           2745     2703      -42     
+ Misses          707      700       -7     
+ Partials        275      265      -10

Impacted Files	Coverage Δ	Complexity Δ
...jpa/query/schema/impl/GraphQLJpaSchemaBuilder.java	91.59% <ø> (-0.03%)	117 <0> (-1)
...hql/jpa/query/schema/impl/JpaPredicateBuilder.java	60.31% <80%> (+0.8%)	114 <0> (+2)	⬆️
.../query/schema/impl/GraphQLJpaQueryDataFetcher.java	91.48% <0%> (-1.07%)	25% <0%> (-1%)
...a/query/schema/impl/QraphQLJpaBaseDataFetcher.java	73.53% <0%> (ø)	149% <0%> (-1%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 6e204fc...887ed28. Read the comment docs.