Remove the restriction from RecursiveContextualValidator that prevents using custom groups.

Seems straight forward.

Given the info from #2820364-77: Entity + Field + Property validation constraints are processed in the incorrect order → , I'd be quite surprised if removing the LogicException would be sufficient to support composite validators.

If we're going to do this it would be good to have some test coverage to prove that it does work (or indeed, as #6 implies, doesn't work).

Tests are indeed needed, this one would be nice though to have. Commenting to put on my list. Think tests will not be very complicated here.

I found a way to support the AtLeastOneOf constraint without any changes to groups. This enables some fun stuff, like:

            constraints:
              AtLeastOneOf:
                constraints:
                  - PluginExists:
                      manager: plugin.manager.menu.link
                      interface: 'Drupal\Core\Menu\MenuLinkInterface'
                  - IdenticalTo:
                      value: ''

Which is awesome and will help in other validation issues to support vlaidation without the need to make a lot of incompatible changes to migrate to needs null etc.

I think this is ready to get a proper review. :)

I reviewed this, looks perfect to me.
Test coverage is great.

I wanted to create an issue for supporting all composite symfony constraints without having to reimplement them, but never got to it.

The good thing is that we ever end up doing it, this should be easily replaceable with that.
For consistency and DX, we should implement all of them. Maybe we need sibling issues for each of the Composites in Symfony\Component\Validator\Constraints?

I'm setting this to RTBC meanwhile.

Not sure this is good, while writing tests for 🐛 PDF files being downloaded RTBC i noted using these tests ends in an error where it thinks the constraint name is an array key. This means in on of the two something is weird i think. Setting abck to NW until i can investigate.

Conclusion, it seems all good. SOrry for the confusion.