Trying to use :componentName to register the class in the registry but even that is evaluation order dependent...

To clarify, I have two entities that reference each other. A has a reference to B, and B can also references entities of type A. There is a circular recursion example in the docs but it isn't mutually recursive like this...

The recursion notation … is useful for self-recursion, but mutual recursion just isn’t possible in the REPL or regular code without specifically spelling out N different things. I think if you give the concrete details of your example perhaps we can suggest a better approach.

The only code I’ve ever seen that tried to do this was something where the author was trying to generate a DOM in Fulcro. E.g. they wanted a Div defsc, which then might contain a P, etc. It was a complete mess, and of course mutually recursive in all sorts of crazy ways. The simple solution was that the defsc was for a Node, and the query included the “type”. Then … worked fine.

Yea I think I can actually model my problem in a way that causes the two entities to collapse into a single entity. This actually results in a cleaner model overall.

Is this in RAD Demo or your own project? I have not messed with this and do not know what datomic/start-databases is supposed to do but I know the demo works (most of the time?). Does the error include any details? E.g. in (ex-data <the error>) ?

So you have just vanilla RAD demo, run its (start) and get this error?

That's correct