Build Environment Setup¶
Requirements¶
Java 8 or newer
LLVM/Clang 15 or newer
sbt
Use nix / devenv.sh¶
The flake.nix and flake.lock files provide a build environment using nix
flakes. Use nix develop to enter a shell with the developer tools available.
This uses devenv.sh to implement the shell environment.
See Using devenv with Nix Flakes
for details on devenv usage and limitation with nix flakes.
See .envrc in this directory for automatically enabling the shell using
direnv.
On Using nix flakes¶
nixpkgs¶
nixpkgs is the most up-to-date distribution with the most
packages. In particular nixpkgs offers
LLVM and garbage collector library builds for multiple platforms. The relative ease to reliably acquire build
tooling makes nixpkgs an attractive option for developers.
There is an additional property of nixpkgs: Content addressed dependencies. The flake lock defines the
required content hash of nixpkgs. Which implies specific builds of LLVM/clang and other dependencies.
Another developer can reliably reproduce the same environment. This also adds some mitigation against supply
chain attacks.
nix flakes¶
nix flakes is a way to describe dependencies on nixpkgs and other repositories. In addition, a nix flake
describes what a repository provides. For example, a compiler repository can describe the exact
dependencies required by the compiler build but also export a build of the compiler as a usable nix package.
For this repository the nix flake uses devenv.sh to as a library to build this nix flake.
This provides a limited devenv environment.
nix flakes has contentious points but, arguably, is uniquely capable. For scala-native, there is additional work required to, for example, enable packages to depend on a nix scala-native compiler build. So this use of nix flakes here is more aspirational than immediately useful. The primary value is providing a reasonably nice developer experience for an automatic and correct developer environment.
