I sent a message to #clojurescript channel about this, but since the ClojureScript compiler behavior I am seeing might have some subtle explanation, I thought I would send it here, too. The README of this tiny sample project should explain everything: https://github.com/jafingerhut/ouroboros

@andy.fingerhut since .bar does not have a require for .foo the compiler can not ensure that .foo is actually compiled before .bar. the default compiler logic when then just process your "inputs" (eg. files in the :source-paths) in an undefined order which ends up compiling .bar before .foo and thus complaining about a var it can't find. problem would get even worse with :parallel-build since with multiple threads it may even sometimes happen to reach (deftype Transient ...) before its use in .bar so the error will only appear occasionally

in general it is not safe to access other namespaces without having an explicit :require for them

So there is an explicit require in namespace foo of bar. Shouldn't that mean that bar must be compiled first always, deterministically?

yes. .bar will be compiled before .foo

circular stuff isn't allowed

How is what you said different than the order I asked about?

sorry, read that wrong. I didn't look at the ns of .foo before 😛

It seems that there is a kind of circularity being allowed here, and warned about, but the compiler goes ahead and generates what appears to be working code, despite that.

yes vars are checked at compile time

but the JS runtime is fine with this at runtime since the "default" behavior is to just warn about missing warns

I haven't examined the JavaScript generated by ClojureScript compiler here, partly since I'm new to JavaScript.

not throw like clojure would

the JS compiler will generated ouroboros.foo.Transient

and JS warns about, but allows, such 'forward references'?

JS doesn't warn no, it is totally fine with that

So I'm guessing that this should not be held up as a good recommended way to write ClojureScript code.

yes. IMHO this should even be a hard error like in Clojure. Not sure why it was made a warning.

Understood. Yeah, hopefully you can understand my confusion at how this was possibly working.

yeah, this works since JS is much more dynamic than the JVM and everything is loaded into the same global scope anyways

so as long as it is loaded into the runtime before it is actually accessed JS will be fine

OK, thanks for the help understanding what is going on. Sounds like a question for #cljs-dev folks for why this is a warning rather than an error.

just doesn't seem very important

one way or the other

heya, would you accept me adding a shadow-cljs section and project template to https://clojurescript.org/guides/project-templates?

I see I can add it as a PR in https://github.com/clojure/clojurescript-site/blob/master/content/guides/project-templates.adoc, but I am not sure if it's welcome to do

added a PR https://github.com/clojure/clojurescript-site/pull/328