Field-local generics information not honored [DATACMNS-697]

[spring-projects-issues]

Max Alexejev opened DATACMNS-697 and commented

In my project, we have an entity called NormalizedProfile, which is a huge collection of generic ListField s. Each listField is a list of Value s plus some metadata. And Value is a (well) single "value" plus some metadata. In our case, atomic "value" is either primitive wrapper, Object or Enum, never a collection (in case it is relevant).

Value<T> gets its generic type from ListField<T> it is enclosed in. Nothing fancy.

In addition to standard java SpringDataMongo config, we customise MappingMongoConverter to stop save and use "_class" field. No polymorphic behaviour is needed in our case, so why not.

Problem is with Object- and Enum- generalized ListField s. After they are saved, they never read as a real object and returned as LHM instead. When I use java.util.List instead of our custom structure, everything works fine.

Please see attached minimal test - j.u.List<Education> testcase succeeds and ListField<Education> fails

---

Affects: 1.10 GA (Fowler)

Attachments:

• GenericListFieldPersistenceTest.java (7.07 kB)

Backported to: 1.10.1 (Fowler SR1), 1.9.3 (Evans SR3), 1.8.6 (Dijkstra SR6)

[spring-projects-issues]

Max Alexejev commented

Executable tests

[spring-projects-issues]

Oliver Drotbohm commented

Thanks for finding this, Max! I've altered TypeDiscoverer to now also consider field-local generics information on parameterized types. Snapshots should be available in a few minutes. I ported the fix back into all currently maintained bugfix branches

[spring-projects-issues]

Max Alexejev commented

Great job, Oliver! Thanks