crossbario
onUserError not implemented
The ABJ does not implement the onUserError, while we have the signature on the Session class, we don't really hook that to anything. https://github.com/crossbario/autobahn-java/blob/9d08106e43346297f603fbae1cee3076f57a22eb/autobahn/src/main/java/io/crossbar/autobahn/wamp/Session.java#L1377
ok, yeah, we actually fire the listeners collected in addUserErrorListener;) there will be multiple locations where we have to add firing the hook .. best in probably to look at the twisted ABPy and component ABPy implementations ..
It seems ABPy Component API does not implement/expose onUserError. Also for Java, it may make sense to give the "user error" in the exceptionally clause of the CompletableFuture. That way developers will know the context where the issue is coming and subsequently better handle it.
Providing errors in a separate, context-independent mechanism is likely to make the API complex