Parallel compilation fails on circular dependencies

Comment made by: mtruyens

Correct: when I disable parallel compilation, the build will (rightfully) fail.

So are you saying if you disable parallel compilation and you try to build it fails with a circular dependency error?

Comment made by: mtruyens

In version 1.9.494 (but also earlier versions, I tried up to 1.9.293), in my fairly large codebase of about 200 CLJC/CLJS namespaces, I have noticed that circular dependencies sometimes cause the compiler to simply idle after initial compilation efforts, without any error indication whatsoever. I then have to kill the compiler, disable parallel building, and restart it, in order to be notified about the actual circular dependency error. This happens both with (1) a clean and then cold recompile of a version of the codebase that happens to contain the error, and (2) during a Figwheel editing session where everything was fine until I happen to introduce the circular dependency. For clarity: in the former case, the compiler does start working during about 10 seconds, but then simply stops and idles (a full recompile takes about 40 seconds on my codebase).

I have tried recreating this error with another codebase, but was unable to do so, so it could be related to the size of the codebase. Do you have any idea where this could be coming from?

fixed https://github.com/clojure/clojurescript/commit/5724f72ad92d62b93cdf1afe19e4bbfc7b6ddecc

We should probably just validate that the inputs do not include a circular dependency before starting parallel compilation.