Build with Nix Env

Nix provides a reproducible development environment: the same dependencies on every machine, isolated from system-wide packages.

Installing Nix

The multi-user (daemon) install is recommended; it supports concurrent builds and better isolation. The single-user option is simpler but skips the background daemon.

# Multi-user installation (recommended for Linux/macOS)
sh <(curl -L https://nixos.org/nix/install) --daemon

# Single-user installation
sh <(curl -L https://nixos.org/nix/install) --no-daemon

See the official Nix installation guide for details.

Setup with Nix Flakes

Enable Flakes

Flakes are Nix's modern approach to reproducible project definitions. Enable them by adding this line to ~/.config/nix/nix.conf (or /etc/nix/nix.conf).

experimental-features = nix-command flakes

Enter Development Shell

cd noir
nix develop

The shell brings its own Crystal, shards, just, and the native libraries Noir links against. The shard dependencies themselves still live in ./lib, so install them once inside the shell and build as usual.

shards install
just build

Alternative: Using Docker with Nix

If you'd rather not install Nix on your host, use the official Nix Docker image. This mounts your local repo into the container.

docker run -it --rm -v $(pwd):/workspace -w /workspace nixos/nix bash

Inside the container, enter the dev shell.

nix develop

Building the Package

The flake also builds the release binary, exactly as nix profile add github:owasp-noir/noir does for users. Same flags as every other official build: --release --no-debug.

just nix-build
./result/bin/noir -h

Updating Dependencies

shards.nix pins every dependency of the Nix build by revision and hash, and it is generated rather than hand-written. Regenerate it whenever shard.lock changes, then verify the two agree.

just nix-update
just nix-check

CI runs the same check, so a forgotten regeneration surfaces in review instead of in the first Nix install after release.

To move the pinned nixpkgs forward, and with it the Crystal toolchain the package builds against:

nix flake update

Next Steps

Proceed with the standard build and test procedures.