A while back i was thinking about pulling together a quick and dirty impl by making the node's read-only JPA entity manager useful for a change, along with some plumbing based on graphql-jpa-query. It's actually pretty easy to do and might be considered as a "lite" impl in cgraph.

That said, the main reason it never happened is that states don't really have relations and i couldn't think of an easy solution for taking reference states and pointers into account.