Contributing

Building gears

The build uses sbt 2 and Scala 3.9.0 on all platforms. It requires:

• JDK 21+ to run sbt and use virtual threads on the JVM.
• On Scala Native: Clang/LLVM 16+ and the Scala Native prerequisites. The build selects Scala Native 0.5.12.
• On Scala.js: Node.js 26+ to run the WebAssembly backend with JSPI. The build selects Scala.js 1.22.0.

All of the needed dependencies can be loaded by the included Nix Flake. If you have nix with flake enabled, run

nix develop

to enter the development environment with all the dependencies loaded. You can also use direnv's use flake to automate this process.

Once done, it should suffice to run

sbt publishLocal

to have Gears compiled and published locally for usage.

Running Tests

sbt test

To test one platform, run sbt rootJVM/test, sbt rootNative/test, or sbt rootJS/test. With sbt 2, separate multiple commands with semicolons inside one quoted argument, for example:

sbt 'scalafmtCheckAll; test'