ci: add nix build package

.gitignore

@@ -8,3 +8,6 @@ plan/
 .DS_Store
 .claude/
 /craft-fonts
+# nix build / nix develop
+/result
+/result-*

AGENTS.md

@@ -119,4 +119,7 @@ of it. Full standard: `../craftrules/standards/never-crash.md`
 ## Map of the code
 `geom`, `color`, `raster`, `tiff` (L0) → `raw`, `codecs`, `meta`, `develop` (L1) → `pipeline` → `catalog` → `engine`
 → `ui-egui`, `mcp` (L5) → apps `lightcraft` (desktop), `lightcraft-cli` (render/commands/MCP). `scenes` generates demo
-photos. `xtask` = tooling (`ci`, `layers`, `assets`, `parity`, `wasm`, `corpus`, `stats`).
+photos. `xtask` = tooling (`ci`, `layers`, `assets`, `parity`, `wasm`, `corpus`, `stats`). `flake.nix` +
+`nix/package.nix` = the Nix package (`nix build` builds both binaries with the craft-fonts input, installs the
+desktop file/icons/AppStream metadata and runs `cargo test --workspace`; `nix develop` = dev shell). Keep it building
+when the workspace layout, `Cargo.lock`, the packaging files or the fonts change; see README → Quick start.

CLAUDE.md

@@ -119,4 +119,7 @@ of it. Full standard: `../craftrules/standards/never-crash.md`
 ## Map of the code
 `geom`, `color`, `raster`, `tiff` (L0) → `raw`, `codecs`, `meta`, `develop` (L1) → `pipeline` → `catalog` → `engine`
 → `ui-egui`, `mcp` (L5) → apps `lightcraft` (desktop), `lightcraft-cli` (render/commands/MCP). `scenes` generates demo
-photos. `xtask` = tooling (`ci`, `layers`, `assets`, `parity`, `wasm`, `corpus`, `stats`).
+photos. `xtask` = tooling (`ci`, `layers`, `assets`, `parity`, `wasm`, `corpus`, `stats`). `flake.nix` +
+`nix/package.nix` = the Nix package (`nix build` builds both binaries with the craft-fonts input, installs the
+desktop file/icons/AppStream metadata and runs `cargo test --workspace`; `nix develop` = dev shell). Keep it building
+when the workspace layout, `Cargo.lock`, the packaging files or the fonts change; see README → Quick start.

README.md

@@ -347,6 +347,31 @@ repo; see [craftrules `standards/fonts.md`](https://github.com/storytold/craftru
 The web build needs the `wasm32-unknown-unknown` target and the matching `wasm-bindgen` CLI
 (`cargo xtask web` prints the exact install command); see [docs/web.md](docs/web.md).
 
+**Nix** builds the desktop app and `lightcraft-cli` (the Nix build always includes the craft-fonts input, so Japanese
+text has glyphs):
+
+```sh
+nix run github:storytold/lightcraft                    # the desktop app
+nix build github:storytold/lightcraft                  # → ./result/bin/{lightcraft,lightcraft-cli}
+nix develop github:storytold/lightcraft                # rust toolchain + native deps + fonts
+```
+
+In a flake configuration (NixOS, home-manager, nix-darwin):
+
+```nix
+# flake.nix
+inputs.lightcraft.url = "github:storytold/lightcraft";
+# optional: build against your own nixpkgs instead of the one LightCraft pins
+# inputs.lightcraft.inputs.nixpkgs.follows = "nixpkgs";
+
+# then, in a NixOS or home-manager module (where `inputs` is in scope):
+nixpkgs.overlays = [ inputs.lightcraft.overlays.default ];   # makes `pkgs.lightcraft` available
+environment.systemPackages = [ pkgs.lightcraft ];           # home-manager: home.packages = [ pkgs.lightcraft ];
+```
+
+`nix build` installs the same desktop file, hicolor icons and AppStream metadata as the .deb/.rpm, and runs
+`cargo test --workspace` as its check phase (skip it with `pkgs.lightcraft.overrideAttrs { doCheck = false; }`).
+
 **Keyboard:** <kbd>G</kbd> grid · <kbd>D</kbd> detail · <kbd>E</kbd> edit · <kbd>C</kbd> crop · <kbd>M</kbd> masking ·
 <kbd>Shift</kbd>+<kbd>P</kbd> presets · <kbd>\\</kbd> original · <kbd>Y</kbd> before/after · <kbd>Z</kbd> zoom ·
 <kbd>J</kbd> clipping · <kbd>⌘Z</kbd> undo · <kbd>⌘/</kbd> all shortcuts.

flake.lock

@@ -0,0 +1,45 @@
+{
+  "nodes": {
+    "craft-fonts": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1791295400,
+        "narHash": "sha256-e+6HpOYoAFTh6mNfGBBw2njnBzcE8W8+Jybv1+dKOCA=",
+        "owner": "storytold",
+        "repo": "craft-fonts",
+        "rev": "abb83316d96aa59c1cf64784289e378fe9fa5695",
+        "type": "github"
+      },
+      "original": {
+        "owner": "storytold",
+        "repo": "craft-fonts",
+        "rev": "abb83316d96aa59c1cf64784289e378fe9fa5695",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1791260994,
+        "narHash": "sha256-Miqqk/ammqnTUxaoCyvtwoPeLbI1ksFyLxi/CazZpWY=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "151fa4e8ddfdd8dd25d945ad94ed54a13de9f6e4",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "craft-fonts": "craft-fonts",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,115 @@
+{
+  description = "LightCraft — photo library and non-destructive raw developer, in pure Rust";
+
+  inputs = {
+    # LightCraft needs edition 2024 and rustc ≥ 1.90, so the flake tracks unstable. Consumers on a
+    # release channel can retarget it: `inputs.lightcraft.inputs.nixpkgs.follows = "nixpkgs";`
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+
+    # Optional build input of the repository: the Japanese fonts (BIZ UDPGothic, BIZ UDMincho,
+    # Shippori Mincho) that `crates/engine/build.rs` embeds when `CRAFT_FONTS_DIR` is set. Official
+    # releases always build with them; without them everything works but Japanese text has no
+    # glyphs. Pinned to the revision the release workflow uses — bump deliberately
+    # (`nix flake update craft-fonts`); craftrules standards/fonts.md.
+    craft-fonts = {
+      url = "github:storytold/craft-fonts/abb83316d96aa59c1cf64784289e378fe9fa5695";
+      flake = false;
+    };
+  };
+
+  outputs =
+    {
+      self,
+      nixpkgs,
+      craft-fonts,
+    }:
+    let
+      inherit (nixpkgs) lib;
+
+      # No x86_64-darwin: the pinned nixpkgs (26.11, "nixos-unstable") dropped support for it. On
+      # an Intel Mac, retarget nixpkgs at a release that still has it, or install the .dmg from the
+      # GitHub release.
+      systems = [
+        "x86_64-linux"
+        "aarch64-linux"
+        "aarch64-darwin"
+      ];
+
+      # The AppStream metadata carries a release date. The flake source's own commit date is
+      # reproducible, unlike "now"; a tarball or dirty tree without one falls back to the epoch.
+      buildDate =
+        let
+          d = self.lastModifiedDate or "";
+        in
+        if builtins.stringLength d >= 8 then
+          "${builtins.substring 0 4 d}-${builtins.substring 4 2 d}-${builtins.substring 6 2 d}"
+        else
+          "1970-01-01";
+
+      packageArgs = {
+        inherit craft-fonts buildDate;
+      };
+
+      forAllSystems = f: lib.genAttrs systems (system: f (import nixpkgs { inherit system; }) system);
+    in
+    {
+      packages = forAllSystems (
+        pkgs: _:
+        let
+          lightcraft = pkgs.callPackage ./nix/package.nix packageArgs;
+        in
+        {
+          inherit lightcraft;
+          default = lightcraft;
+        }
+      );
+
+      # `nixpkgs.overlays = [ inputs.lightcraft.overlays.default ]` → `pkgs.lightcraft` everywhere.
+      overlays.default = final: _prev: {
+        lightcraft = final.callPackage ./nix/package.nix packageArgs;
+      };
+
+      devShells = forAllSystems (
+        pkgs: system:
+        let
+          lightcraft = self.packages.${system}.lightcraft;
+        in
+        {
+          default = pkgs.mkShell (
+            {
+              # The package's own native inputs, so `cargo build` in the shell needs no extra setup.
+              inputsFrom = [ lightcraft ];
+              packages = with pkgs; [
+                cargo
+                rustc
+                clippy
+                rustfmt
+                rust-analyzer
+              ];
+              # `cargo run` dlopens the Vulkan loader and libxkbcommon like the packaged binary.
+              LD_LIBRARY_PATH = lib.makeLibraryPath lightcraft.passthru.runtimeLibs;
+              RUST_BACKTRACE = "1";
+            }
+            // lib.optionalAttrs (craft-fonts != null) {
+              # Japanese glyphs in `cargo run` too; build.rs reads this as CRAFT_FONTS_DIR.
+              CRAFT_FONTS_DIR = toString craft-fonts;
+            }
+          );
+        }
+      );
+
+      checks = forAllSystems (
+        pkgs: system: {
+          lightcraft = self.packages.${system}.lightcraft;
+
+          # `nix fmt` formats the flake; this keeps it formatted.
+          formatting = pkgs.runCommand "lightcraft-nix-formatting" { nativeBuildInputs = [ pkgs.nixfmt ]; } ''
+            nixfmt --check ${./flake.nix} ${./nix}
+            touch $out
+          '';
+        }
+      );
+
+      formatter = forAllSystems (pkgs: _: pkgs.nixfmt);
+    };
+}

nix/package.nix

@@ -0,0 +1,206 @@
+# LightCraft — the desktop app (`lightcraft`) and the CLI/MCP server (`lightcraft-cli`), built from
+# this repository:
+#
+#   nix build          # → ./result/bin/lightcraft, ./result/bin/lightcraft-cli
+#
+# Kept in step with the release workflow (.github/workflows/release.yml) and packaging/env.sh:
+#   * `Cargo.lock` drives the dependencies (`cargoLock`), so there is no vendorHash to bump — only
+#     crates.io, no git sources;
+#   * `CRAFT_FONTS_DIR` embeds the Japanese fonts from storytold/craft-fonts (the `craft-fonts`
+#     flake input); without it everything builds and runs, but Japanese text has no glyphs;
+#   * the desktop file, hicolor icons and AppStream metadata are the same files the .deb/.rpm ship
+#     (packaging/linux/), so `apt` and NixOS users see one identical LightCraft;
+#   * `doCheck` runs `cargo test --workspace`, what `cargo xtask ci` runs. `nix build` runs it too;
+#     `pkgs.lightcraft.overrideAttrs { doCheck = false; }` skips it for a faster, build-only install.
+#
+# Everything in the product is pure Rust (no C/C++ dependencies), so this needs no build system
+# beyond cargo plus the windowing headers winit's build scripts look for.
+{
+  lib,
+  stdenv,
+  rustPlatform,
+  pkg-config,
+  makeWrapper,
+  # Windowing/GPU libraries: needed at build time by the crates that link them, at run time by the
+  # ones that open them with dlopen() (see `runtimeLibs`), and by the dev shell (flake.nix).
+  wayland,
+  wayland-scanner,
+  libxkbcommon,
+  libx11,
+  libxcb,
+  libxcursor,
+  libxi,
+  libxrandr,
+  vulkan-loader,
+  # Validates the desktop file and the AppStream metadata we install (as CI does).
+  desktop-file-utils,
+  appstream,
+  # Adds the driver search path (/run/opengl-driver/lib) to the binaries' RPATH so wgpu finds the
+  # installed Vulkan driver on NixOS. Optional: harmless on nixpkgs without it.
+  autoAddDriverRunpath ? null,
+  # storytold/craft-fonts checkout (flake input). `null` builds without Japanese glyphs.
+  craft-fonts ? null,
+  # Release date for the AppStream metadata (YYYY-MM-DD); the flake derives it from its own commit.
+  buildDate ? "1970-01-01",
+}:
+
+let
+  root = ../.;
+
+  # The version lives in exactly one place: `[workspace.package] version` in the root Cargo.toml.
+  version = (builtins.fromTOML (builtins.readFile (root + "/Cargo.toml"))).workspace.package.version;
+
+  isLinux = stdenv.hostPlatform.isLinux;
+
+  # AppStream id: also the desktop file name, and the icon name in share/icons/hicolor.
+  appId = "ai.storyteller.lightcraft";
+
+  # Libraries the binaries open at run time with dlopen(): nothing links them, so no RPATH points at
+  # them — winit loads libxkbcommon/libxcb, wgpu the Vulkan loader (NixOS patches that loader to
+  # find the drivers in /run/opengl-driver). The wrapper below points LD_LIBRARY_PATH here.
+  runtimeLibs = lib.optionals isLinux [
+    libxkbcommon
+    wayland
+    libx11
+    libxcb
+    libxcursor
+    libxi
+    libxrandr
+    vulkan-loader
+  ];
+
+  # The two native binaries. The wasm app (apps/lightcraft-web) is built by `cargo xtask web`, not
+  # here; xtask is tooling.
+  binaries = [
+    "lightcraft"
+    "lightcraft-cli"
+  ];
+in
+rustPlatform.buildRustPackage {
+  pname = "lightcraft";
+  inherit version;
+
+  src = lib.cleanSourceWith {
+    src = lib.cleanSource root;
+    # The Nix files are not part of the build: editing them must not rebuild any Rust.
+    filter =
+      path: _type:
+      !(builtins.elem (baseNameOf path) [
+        "flake.nix"
+        "flake.lock"
+        "nix"
+      ]);
+  };
+
+  cargoLock.lockFile = root + "/Cargo.lock";
+
+  # Both binaries, as the .deb/.rpm install them (`packaging/linux/package.sh`).
+  cargoBuildFlags = [
+    "--locked"
+    "-p"
+    "lightcraft"
+    "-p"
+    "lightcraft-cli"
+  ];
+
+  # `cargo xtask ci` runs `cargo test --workspace`. Tests that need what the sandbox cannot have
+  # skip themselves with a note: corpus/ (gitignored, `cargo xtask corpus --download`) and the GPU
+  # equivalence tests (no adapter).
+  cargoTestFlags = [ "--workspace" ];
+
+  # One test thread at a time (RUST_TEST_THREADS=1). `lightcraft-catalog`'s `tests_lock` tests share
+  # a process-global resource: `flock` is inherited across `fork`, so a child process that another
+  # test forked keeps the parent's just-released library lock alive until its `execve` closes the
+  # (CLOEXEC) fd — long enough that the sibling test sees a spurious `LockError::InUse`, on ~30 % of
+  # runs on a many-core machine. Serializing the tests keeps `nix build` deterministic without
+  # touching the repository. The underlying window (any `fork` in a process holding the library
+  # lock — the app spawns `xdg-open`/`open`/`explorer` and `sysctl`) is a product-level question:
+  # `LibraryLock::acquire` could retry on `WouldBlock` for a few hundred ms before reporting InUse.
+  dontUseCargoParallelTests = true;
+
+  strictDeps = true;
+
+  nativeBuildInputs = [
+    pkg-config
+  ]
+  ++ lib.optionals isLinux [
+    makeWrapper
+    wayland-scanner
+    desktop-file-utils
+    appstream
+  ]
+  ++ lib.optionals (isLinux && autoAddDriverRunpath != null) [ autoAddDriverRunpath ];
+
+  buildInputs = lib.optionals isLinux [
+    wayland
+    libxkbcommon
+    libx11
+    libxcb
+    libxcursor
+    libxi
+    libxrandr
+  ];
+
+  env = lib.optionalAttrs (craft-fonts != null) {
+    CRAFT_FONTS_DIR = toString craft-fonts;
+    # A malformed font input must fail the build rather than silently ship without glyphs.
+    CRAFT_FONTS_REQUIRED = "1";
+  };
+
+  postInstall = ''
+    # Desktop integration: byte-for-byte the files the .deb/.rpm/.AppImage install.
+    install -Dm644 packaging/linux/${appId}.desktop $out/share/applications/${appId}.desktop
+    install -Dm644 packaging/linux/${appId}.mime.xml $out/share/mime/packages/${appId}.xml
+    cp -r assets/app-icon/hicolor $out/share/icons/
+    install -d $out/share/metainfo
+    substitute packaging/linux/${appId}.metainfo.xml.in \
+      $out/share/metainfo/${appId}.metainfo.xml \
+      --subst-var-by VERSION ${version} \
+      --subst-var-by DATE ${buildDate}
+
+    # Licences for everything embedded in the binaries: Inter, the app icon, each craft font.
+    doc=$out/share/doc/lightcraft
+    install -Dm644 -t "$doc" \
+      README.md LICENSE-MIT LICENSE-APACHE NOTICE \
+      assets/ATTRIBUTION.md assets/fonts/OFL-Inter.txt
+  ''
+  + lib.optionalString (craft-fonts != null) ''
+    for lic in ${toString craft-fonts}/fonts/*/OFL.txt; do
+      install -Dm644 "$lic" "$doc/OFL-$(basename "$(dirname "$lic")").txt"
+    done
+  ''
+  + lib.optionalString isLinux ''
+    desktop-file-validate $out/share/applications/${appId}.desktop
+    XDG_CACHE_HOME=$TMPDIR/.cache appstreamcli validate --no-net \
+      $out/share/metainfo/${appId}.metainfo.xml
+
+    # makeWrapper keeps the binaries working when the libs above are only dlopen'd.
+    for bin in ${lib.concatStringsSep " " (map (b: "$out/bin/" + b) binaries)}; do
+      wrapProgram "$bin" --prefix LD_LIBRARY_PATH : "${lib.makeLibraryPath runtimeLibs}"
+    done
+  '';
+
+  passthru = {
+    # Shared with the dev shell so `cargo run` inside `nix develop` finds the same dlopen'd libs.
+    inherit runtimeLibs;
+  };
+
+  meta = {
+    description = "Photo library and non-destructive raw developer";
+    longDescription = ''
+      LightCraft organises a photo library and develops raw files non-destructively: masks,
+      presets, colour grading, local adjustments and batch export, driven by the same command
+      layer as its UI. It ships with lightcraft-cli, a headless renderer, command runner and MCP
+      server for AI agents.
+    '';
+    homepage = "https://getartcraft.com/apps/lightcraft";
+    license = with lib.licenses; [
+      mit
+      asl20
+    ];
+    sourceProvenance = with lib.sourceTypes; [ fromSource ];
+    platforms = lib.platforms.linux ++ lib.platforms.darwin;
+    # `nix run` and the desktop entry both start the GUI.
+    mainProgram = "lightcraft";
+  };
+}