Nix: initial setup

.github/dependabot.yml

+version: 2
+updates:
+- package-ecosystem: "github-actions"
+  directory: "/"
+  schedule:
+      interval: "weekly"

.github/workflows/nix.yml

+name: "CI - Nix"
+
+on:
+  push:
+    branches:
+      - devel
+      - master
+  pull_request:
+    branches:
+      - devel
+      - master
+
+jobs:
+  tests:
+    name: "Nix build on ${{ matrix.os }}"
+    runs-on: "${{ matrix.os }}-latest"
+    strategy:
+      matrix:
+        os: [ubuntu, macos]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: cachix/install-nix-action@v27
+      - uses: cachix/cachix-action@v15
+        with:
+          name: gepetto
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+      - run: nix build -L

.github/workflows/update-flake-lock.yml

+name: update-flake-lock
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '0 18 23 * *'
+
+jobs:
+  lockfile:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      - name: Install Nix
+        uses: DeterminateSystems/nix-installer-action@main
+      - name: Update flake.lock
+        uses: DeterminateSystems/update-flake-lock@main
+        with:
+          token: ${{ secrets.GH_TOKEN_FOR_UPDATES }}

CHANGELOG.md

@@ -11,6 +11,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Update Go2 collision for convex hull of mesh and remove "Head_upper", "Head_lower", "XX_calflower", "XX_calflower1" links and joints ([#260](https://github.com/Gepetto/example-robot-data/pull/260))
 - Fix ROS2 installation ([#261](https://github.com/Gepetto/example-robot-data/pull/261))
 - Add tiago pro ([#265](https://github.com/Gepetto/example-robot-data/pull/265))
+- Add nix flake
 
 ## [4.2.0] - 2024-12-08
 

flake.lock

+{
+  "nodes": {
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": "nixpkgs-lib"
+      },
+      "locked": {
+        "lastModified": 1741352980,
+        "narHash": "sha256-+u2UunDA4Cl5Fci3m7S643HzKmIDAe+fiXrLqYsR2fs=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "f4330d22f1c5d2ba72d3d22df5597d123fdb60a9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1742069588,
+        "narHash": "sha256-C7jVfohcGzdZRF6DO+ybyG/sqpo1h6bZi9T56sxLy+k=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "c80f6a7e10b39afcc1894e02ef785b1ad0b0d7e5",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-lib": {
+      "locked": {
+        "lastModified": 1740877520,
+        "narHash": "sha256-oiwv/ZK/2FhGxrCkQkB83i7GnWXPPLzoqFHpDD3uYpk=",
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "rev": "147dee35aab2193b174e4c0868bd80ead5ce755c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-parts": "flake-parts",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

+{
+  description = "Set of robot URDFs for benchmarking and developed examples";
+
+  inputs = {
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  };
+
+  outputs =
+    inputs:
+    inputs.flake-parts.lib.mkFlake { inherit inputs; } {
+      systems = inputs.nixpkgs.lib.systems.flakeExposed;
+      perSystem =
+        {
+          pkgs,
+          self',
+          ...
+        }:
+        {
+          apps.default = {
+            type = "app";
+            program = pkgs.python3.withPackages (_: [ self'.packages.default ]);
+          };
+          devShells.default = pkgs.mkShell {
+            inputsFrom = [ self'.packages.default ];
+            packages = [ (pkgs.python3.withPackages (p: [p.tomlkit])) ]; # for "make release"
+          };
+          packages = {
+            default = self'.packages.example-robot-data;
+            example-robot-data = pkgs.python3Packages.example-robot-data.overrideAttrs (_: {
+              src = pkgs.lib.fileset.toSource {
+                root = ./.;
+                fileset = pkgs.lib.fileset.unions [
+                  ./CMakeLists.txt
+                  ./colcon.pkg
+                  ./include
+                  ./package.xml
+                  ./pyproject.toml
+                  ./python
+                  ./robots
+                  ./unittest
+                ];
+              };
+            });
+          };
+        };
+    };
+}