PersistentCollection::matching() lacks support for inheritance

[arnaud-lb]

PersistentCollection::matching() uses the entity persister, which in turn uses ResultSetMappingBuilder, which doesn't support inheritance. Trying to call matching() throws an exception with the following message:

ResultSetMapping builder does not currently support your inheritance scheme

Is this fully intentional, or is this feature missing because of a lack of resources ? If I made a PR, would you be willing to accept it ?

[Ocramius]

or is this feature missing because of a lack of resources ?

Likely the case

If I made a PR, would you be willing to accept it ?

Depends on the test case that you can provide for this scenario. It would target 3.x though.

[arnaud-lb]

3.x seems far away, is 2.x completely freezed ?

[Ocramius]

Yes, only non-breaking bug fixes in 2.x

[ndench]

It certainly looks like the exception was added because of a lack of resources. You can see when the ResultSetMappingBuilder was created the exception exists which leads me to believe that handling inheritance was considered an edge case they didn't want to deal with at the time.

It appears that over time, the ResultSetMappingBuilder has been updated to a point where it largely supports inheritance, you can the check was loosened in this PR to support single table inheritance but only for concrete classes (ie. not the abstract base class).

Very superficial testing for me locally say that we can also support join table inheritance for concrete classes as well so we should be able to loosen the check as long as we add test cases to prove it works.