juliaup-nix

Nix flake packaging juliaup — the official Julia version manager.

Juliaup is not in nixpkgs. This flake builds juliaup from source using rustPlatform.buildRustPackage, and provides pinned Julia binaries in the Nix store for fully reproducible deployments.

What this provides

Package	Binary	Description
juliaup (default)	juliaup	Julia version manager CLI, built from source
julia	julia	Latest stable (1.13.0) — pinned in the Nix store
julia-lts	julia	LTS (1.10.9) — pinned in the Nix store
julia-1_13_0	—	Raw Julia 1.13.0 binary (no wrapper)
julia-1_10_9	—	Raw Julia 1.10.9 binary (no wrapper)

julia and julia-lts both expose /bin/julia — install only one at a time in home.packages.

Why a separate julia wrapper? juliaup uses current_exe() (resolves symlinks via /proc/self/exe on Linux) to decide whether to launch Julia or show its own CLI. A plain julia → juliaup symlink always resolves to the store path, so juliaup sees itself as juliaup and shows its own help. The wrappers simply exec the pinned binary from the Nix store — no runtime dispatch, no ~/.julia/juliaup/ dependency.

Why not environment.systemPackages? The julia package must go in home.packages (user-level), not environment.systemPackages, to avoid binary conflicts with julia-bin pulled transitively by tools such as quarto.

Quick start

# Try juliaup without installing
nix run github:s-celles/juliaup-nix -- add release

# Run pinned Julia directly
nix run github:s-celles/juliaup-nix#julia      # latest stable (1.13.0)
nix run github:s-celles/juliaup-nix#julia-lts  # LTS (1.10.9)

NixOS / Home Manager

Add the input to your flake.nix:

inputs = {
  nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
  juliaup-nix = {
    url = "github:s-celles/juliaup-nix";
    inputs.nixpkgs.follows = "nixpkgs";
  };
};

Install juliaup as a system package and the julia wrapper as a user package:

# NixOS module — system-level (juliaup CLI only)
environment.systemPackages = [
  inputs.juliaup-nix.packages.${pkgs.stdenv.hostPlatform.system}.juliaup
];

# Home Manager — user-level: choose one julia wrapper
home.packages = [
  inputs.juliaup-nix.packages.${pkgs.stdenv.hostPlatform.system}.julia      # latest stable
  # inputs.juliaup-nix.packages.${pkgs.stdenv.hostPlatform.system}.julia-lts  # or LTS
];

After rebuild:

julia --version  # no download required — served from the Nix store
juliaup add 1.9 && juliaup default 1.9  # juliaup still manages other versions

Reproducibility

• No runtime download: julia works immediately after nixos-rebuild switch.
• Pinned binary: Julia version is fixed by the flake hash — bump the flake revision to upgrade.
• juliaup still useful: for accessing other Julia versions on demand (juliaup add 1.9, etc.).

Updating Julia version

Update the relevant mkJuliaBin call in flake.nix with the new version's URLs and hashes, then bump the flake in your configuration:

nix flake update juliaup-nix

About flake.lock

The flake.lock pins nixpkgs and flake-utils versions for reproducible builds. Commit it alongside flake.nix.