this is the definition https://github.com/clojure/core.async/blob/b85d2dcf446ca0235edf25a199a74de8fb910fe6/src/java/clojure/core/async/Mutex.java

that file was last edited in 2013

but the latest version doesn't have java code anymore

maybe I shoud clear the target directory

that's true - the java code is still in github, but the released artifacts for recent versions don't have the classfiles

but also, the references to Mutex are removed from the clojure.core.async.impl.mutex ns

what file is it trying to load when you see that error?

also, I wonder why the github code doesn't reflect recent releases

Why don't you think it reflects recent releases?

in github, theres a Mutex.java, in the jar from maven, there's no corresponding class file, and the mutex definition doesn't use that class any more

And the pom isn't setup to compile Java code

So there is nothing to package

oh, I missed this, you're right. Mutex.java is still in the repo, but is now a no-op, and the mutex impl doesn't try to use it any more

It doesn't appear to be in the repo any more at least on master either

I must have ended up looking at the wrong version due to bad github js or user error

@U0NBGRGD6 i had a similar problem some time ago and i had to do a dependency tree in order to figure out what was bringing in a very old version of core.async

i don't recall exactly what it was anymore but i vaguely remember something with an old clojurescript version

Yes, I finally solve the problem by delete the target directory.