Mill, Cask, and SBT

Question

I am following this tutorial: https://www.lihaoyi.com/post/SimpleWebandApiServerswithScala.html. I get to the part where I run "./mill -w app.runBackground", and I receive the following error:

"[error] java.lang.RuntimeException: /packages cannot be represented as URI".

I've tried the advice in this ticket, but it didn't work for me: Scala: packages cannot be represented as URI.

"java -version" gives me "openjdk version "17.0.2" 2022-01-18".

"scala --version" gives me 3.1.3.

Any thoughts?

Answer 1

That is a bug in the Scala compiler. Please update to the latest bugfix release of the branch you're using, i. e. 2.13.8 or 2.12.16.

The Scala version installed on the system is irrelevant as Mill doesn't use it. It will instead download the version that you specify in your build. So you need to add something like def scalaVersion = "2.13.8".