niri/flake.nix

# This flake file is community maintained
{
  description = "Niri: A scrollable-tiling Wayland compositor.";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    nix-filter.url = "github:numtide/nix-filter";

    # NOTE: This is not necessary for end users
    # You can omit it with `inputs.rust-overlay.follows = ""`
    rust-overlay = {
      url = "github:oxalica/rust-overlay";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs =
    {
      self,
      nixpkgs,
      nix-filter,
      rust-overlay,
    }:
    let
      inherit (nixpkgs) lib;
      # Support all Linux systems that the nixpkgs flake exposes
      systems = lib.intersectLists lib.systems.flakeExposed lib.platforms.linux;

      forAllSystems = lib.genAttrs systems;
      nixpkgsFor = forAllSystems (system: nixpkgs.legacyPackages.${system});
    in
    {
      checks = forAllSystems (system: {
        # We use the debug build here to save a bit of time
        inherit (self.packages.${system}) niri-debug;
      });

      devShells = forAllSystems (
        system:
        let
          pkgs = nixpkgsFor.${system};
          inherit (self.packages.${system}) niri;
        in
        {
          default = pkgs.mkShell {
            packages = [
              # NOTE: Nixpkgs' Rust toolchain isn't used here as we prefer
              # a nightly toolchain for development, and *require* a nightly
              # `rustfmt`
              rust-overlay.packages.${system}.rust-nightly

              pkgs.rust-analyzer
            ];

            nativeBuildInputs = [
              pkgs.clang
              pkgs.pkg-config
              pkgs.wrapGAppsHook4 # For `niri-visual-tests`
            ];

            buildInputs = niri.buildInputs ++ [
              pkgs.libadwaita # For `niri-visual-tests`
            ];

            env = {
              inherit (niri) LIBCLANG_PATH;

              # WARN: Do not overwrite this variable in your shell!
              # It is required for `dlopen()` to work on some libraries; see the comment
              # in the package expression
              #
              # This should only be set with `CARGO_BUILD_RUSTFLAGS="$CARGO_BUILD_RUSTFLAGS -C your-flags"`
              inherit (niri) CARGO_BUILD_RUSTFLAGS;
            };
          };
        }
      );

      formatter = forAllSystems (system: nixpkgsFor.${system}.nixfmt-rfc-style);

      packages = forAllSystems (
        system:
        let
          inherit (self.overlays.default nixpkgsFor.${system} null) niri;
        in
        {
          inherit niri;

          # NOTE: This is for development purposes only
          #
          # It is primarily to help with quickly iterating on
          # changes made to the above expression - though it is
          # also not stripped in order to better debug niri itself
          niri-debug = niri.overrideAttrs (
            newAttrs: oldAttrs: {
              pname = oldAttrs.pname + "-debug";

              cargoBuildType = "debug";
              cargoCheckType = newAttrs.cargoBuildType;

              dontStrip = true;
            }
          );

          default = niri;
        }
      );

      overlays.default = final: _: {
        niri = final.callPackage (
          {
            cairo,
            clang,
            dbus,
            libGL,
            libclang,
            libdisplay-info,
            libinput,
            libseat,
            libxkbcommon,
            mesa,
            pango,
            pipewire,
            pkg-config,
            rustPlatform,
            systemd,
            wayland,
            withDbus ? true,
            withSystemd ? true,
            withScreencastSupport ? true,
            withDinit ? false,
          }:

          rustPlatform.buildRustPackage {
            pname = "niri";
            version = self.shortRev or self.dirtyShortRev or "unknown";

            src = nix-filter.lib.filter {
              root = self;
              include = [
                "niri-config"
                "niri-ipc"
                "niri-visual-tests"
                "resources"
                "src"
                ./Cargo.lock
                ./Cargo.toml
              ];
            };

            postPatch = ''
              patchShebangs resources/niri-session
              substituteInPlace resources/niri.service \
                --replace-fail '/usr/bin' "$out/bin"
            '';

            cargoLock = {
              # NOTE: This is only used for Git dependencies
              allowBuiltinFetchGit = true;
              lockFile = ./Cargo.lock;
            };

            strictDeps = true;

            nativeBuildInputs = [
              clang
              pkg-config
            ];

            buildInputs =
              [
                cairo
                dbus
                libGL
                libdisplay-info
                libinput
                libseat
                libxkbcommon
                mesa # libgbm
                pango
                wayland
              ]
              ++ lib.optional (withDbus || withScreencastSupport || withSystemd) dbus
              ++ lib.optional withScreencastSupport pipewire
              # Also includes libudev
              ++ lib.optional withSystemd systemd;

            buildFeatures =
              lib.optional withDbus "dbus"
              ++ lib.optional withDinit "dinit"
              ++ lib.optional withScreencastSupport "xdp-gnome-screencast"
              ++ lib.optional withSystemd "systemd";
            buildNoDefaultFeatures = true;

            postInstall =
              ''
                install -Dm644 resources/niri.desktop -t $out/share/wayland-sessions
                install -Dm644 resources/niri-portals.conf -t $out/share/xdg-desktop-portal
              ''
              + lib.optionalString withSystemd ''
                install -Dm755 resources/niri-session $out/bin/niri-session
                install -Dm644 resources/niri{.service,-shutdown.target} -t $out/share/systemd/user
              '';

            env = {
              LIBCLANG_PATH = lib.getLib libclang + "/lib";

              # Force linking with libEGL and libwayland-client
              # so they can be discovered by `dlopen()`
              CARGO_BUILD_RUSTFLAGS = toString (
                map (arg: "-C link-arg=" + arg) [
                  "-Wl,--push-state,--no-as-needed"
                  "-lEGL"
                  "-lwayland-client"
                  "-Wl,--pop-state"
                ]
              );
            };

            passthru = {
              providedSessions = [ "niri" ];
            };

            meta = {
              description = "Scrollable-tiling Wayland compositor";
              homepage = "https://github.com/YaLTeR/niri";
              license = lib.licenses.gpl3Only;
              mainProgram = "niri";
              platforms = lib.platforms.linux;
            };
          }
        ) { };
      };
    };
}