feat: add optional nix flake support

refs #208

refs #221

refs #264

10 files changed, 329 insertions, 3 deletions

diff --git a/.github/workflows/nix.yml b/.github/workflows/nix.yml
new file mode 100644
index 00000000..c8e8e6ff
--- /dev/null
+++ b/.github/workflows/nix.yml
@@ -0,0 +1,34 @@
+name: Nix
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+  push:
+    branches: [master]
+    paths-ignore:
+      - "website/**"
+
+permissions:
+  contents: read
+
+concurrency:
+  group: nix-${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  flake-check:
+    name: flake check
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+        with:
+          persist-credentials: false
+
+      - name: Run Nix flake check
+        run: |
+          docker run --rm \
+            -v "$PWD:/work" \
+            -w /work \
+            docker.io/nixos/nix:2.31.2 \
+            sh -c 'nix --extra-experimental-features "nix-command flakes" flake check --print-build-logs && nix --extra-experimental-features "nix-command flakes" flake check --all-systems --no-build --print-build-logs'
diff --git a/.gitignore b/.gitignore
index d2eaa147..51110c52 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,5 @@ __pycache__/
 /.pi/todos
 /.pi/issues
 /.pi/cache
+/result
+/result-*
diff --git a/build.rs b/build.rs
index c68d420a..cda19840 100644
--- a/build.rs
+++ b/build.rs
@@ -32,9 +32,14 @@ fn main() {
     println!("cargo:rerun-if-changed=vendor/libghostty-vt.vendor.json");
     println!("cargo:rerun-if-changed=vendor/libghostty-vt/build.zig");
     println!("cargo:rerun-if-changed=vendor/libghostty-vt/build.zig.zon");
+    println!("cargo:rerun-if-changed=vendor/libghostty-vt/include");
+    println!("cargo:rerun-if-changed=vendor/libghostty-vt/pkg");
+    println!("cargo:rerun-if-changed=vendor/libghostty-vt/src");
     println!("cargo:rerun-if-changed=vendor/libghostty-vt/VERSION");
     println!("cargo:rerun-if-env-changed=LIBGHOSTTY_VT_OPTIMIZE");
     println!("cargo:rerun-if-env-changed=LIBGHOSTTY_VT_SIMD");
+    println!("cargo:rerun-if-env-changed=LIBGHOSTTY_VT_ZIG_SYSTEM_DIR");
+    println!("cargo:rerun-if-env-changed=ZIG");
 
     let manifest_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR"));
     let vendored_dir = manifest_dir.join("vendor/libghostty-vt");
@@ -47,13 +52,20 @@ fn main() {
         .trim()
         .to_string();
 
-    let status = Command::new("zig")
+    let zig = env::var("ZIG").unwrap_or_else(|_| "zig".into());
+    let mut command = Command::new(zig);
+    command
         .arg("build")
         .arg("-Demit-lib-vt")
         .arg(format!("-Doptimize={optimize}"))
         .arg(format!("-Dsimd={simd}"))
         .arg(format!("-Dtarget={zig_target}"))
-        .arg(format!("-Dversion-string={version_string}"))
+        .arg(format!("-Dversion-string={version_string}"));
+    if let Ok(system_dir) = env::var("LIBGHOSTTY_VT_ZIG_SYSTEM_DIR") {
+        command.arg("--system").arg(system_dir);
+    }
+
+    let status = command
         .current_dir(&vendored_dir)
         .status()
         .expect("failed to execute zig build for vendored libghostty-vt");
diff --git a/docs/next/CHANGELOG.md b/docs/next/CHANGELOG.md
index f4a8a6de..de3ada07 100644
--- a/docs/next/CHANGELOG.md
+++ b/docs/next/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## Unreleased
 
 ### Added
+- Added optional Nix flake support for building, running, installing, and developing Herdr with Nix. (#208, #221, #264)
 - Added `terminal.new_cwd` to choose whether new panes, tabs, and workspaces follow the source pane/workspace, start in `$HOME`, use Herdr's process directory, or use a fixed path.
 - Added `herdr integration install omp` for OMP's `.omp` extension directory. The extension reports OMP pane state through Herdr's socket API without relying on native `omp` process detection.
 - Added CLI and socket API support for Git worktrees with `herdr worktree list/create/open/remove`, optional worktree provenance on workspace responses, and client/server protocol version 10.
diff --git a/docs/next/README.md b/docs/next/README.md
index 16a9fd1c..99e99e6c 100644
--- a/docs/next/README.md
+++ b/docs/next/README.md
@@ -295,6 +295,20 @@ cargo build --release
 ./target/release/herdr
 ```
 
+## nix
+
+Herdr provides optional Nix flake outputs for users who already use Nix. The flake builds Herdr from source.
+
+```bash
+nix run github:ogulcancelik/herdr
+nix build github:ogulcancelik/herdr
+nix develop github:ogulcancelik/herdr
+```
+
+The flake exposes `packages.<system>.default`, `apps.<system>.default`, `devShells.<system>.default`, and `overlays.default`.
+
+Update through the same Nix workflow you used to install Herdr. For profile installs, run `nix profile list` and then `nix profile upgrade <index-or-name>`. For flake inputs, run `nix flake update herdr` in your own flake and rebuild.
+
 ## testing
 
 ```bash
diff --git a/docs/next/website/src/content/docs/install.mdx b/docs/next/website/src/content/docs/install.mdx
index dda2dc27..69834567 100644
--- a/docs/next/website/src/content/docs/install.mdx
+++ b/docs/next/website/src/content/docs/install.mdx
@@ -33,6 +33,35 @@ Herdr checks for new releases and notifies you in the app. You can update manual
 herdr update
 ```
 
+## Install with Nix
+
+If you already use Nix, Herdr provides a flake that builds Herdr from source:
+
+```bash
+nix run github:ogulcancelik/herdr
+nix build github:ogulcancelik/herdr
+nix profile install github:ogulcancelik/herdr
+```
+
+The flake also exposes a development shell:
+
+```bash
+nix develop github:ogulcancelik/herdr
+```
+
+Update through the same Nix workflow you used to install Herdr. For a profile install, list your profile entries and upgrade the Herdr entry:
+
+```bash
+nix profile list
+nix profile upgrade <index-or-name>
+```
+
+If Herdr is an input in your own flake, update that input and rebuild your system, Home Manager, or development environment:
+
+```bash
+nix flake update herdr
+```
+
 ## Download manually
 
 You can also download a binary from [GitHub releases](https://github.com/ogulcancelik/herdr/releases).
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 00000000..421a64fc
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1779357205,
+        "narHash": "sha256-cCO8aTqss5x9Ky8GWkpY0Hy5fyTZEbtifSUV8QjSzic=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "f83fc3c307e74bc5fd5adb7eb6b8b13ffd2a36e1",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 00000000..3a91a3ca
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,82 @@
+{
+  description = "herdr — terminal workspace manager for AI coding agents";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  };
+
+  outputs =
+    { self, nixpkgs }:
+    let
+      lib = nixpkgs.lib;
+      systems = [
+        "x86_64-linux"
+        "aarch64-linux"
+        "x86_64-darwin"
+        "aarch64-darwin"
+      ];
+      forAllSystems = lib.genAttrs systems;
+      pkgsFor = system: import nixpkgs { inherit system; };
+    in
+    {
+      packages = forAllSystems (
+        system:
+        let
+          pkgs = pkgsFor system;
+          herdr = pkgs.callPackage ./nix/package.nix { };
+        in
+        {
+          inherit herdr;
+          default = herdr;
+        }
+      );
+
+      apps = forAllSystems (system: {
+        default = {
+          type = "app";
+          program = "${self.packages.${system}.default}/bin/herdr";
+          meta.description = "Run Herdr";
+        };
+      });
+
+      checks = forAllSystems (system: {
+        herdr = self.packages.${system}.default;
+        default = self.checks.${system}.herdr;
+      });
+
+      devShells = forAllSystems (
+        system:
+        let
+          pkgs = pkgsFor system;
+        in
+        {
+          default = pkgs.mkShell {
+            name = "herdr-dev";
+            packages = with pkgs; [
+              cargo
+              cargo-nextest
+              clippy
+              cmake
+              just
+              ninja
+              pkg-config
+              rustc
+              rustfmt
+              zig_0_15
+            ];
+
+            env = {
+              LIBGHOSTTY_VT_OPTIMIZE = "Debug";
+              LIBGHOSTTY_VT_SIMD = "true";
+            };
+          };
+        }
+      );
+
+      formatter = forAllSystems (system: (pkgsFor system).nixfmt);
+
+      overlays.default = final: _prev: {
+        herdr = final.callPackage ./nix/package.nix { };
+      };
+    };
+}
diff --git a/nix/package.nix b/nix/package.nix
new file mode 100644
index 00000000..ba9206d8
--- /dev/null
+++ b/nix/package.nix
@@ -0,0 +1,76 @@
+{
+  lib,
+  rustPlatform,
+  callPackage,
+  runCommand,
+  zig_0_15,
+  zstd,
+  pkg-config,
+  git,
+}:
+
+let
+  manifest = lib.importTOML ../Cargo.toml;
+  zigDeps = callPackage ../vendor/libghostty-vt/build.zig.zon.nix {
+    name = "herdr-libghostty-vt-zig-cache";
+    inherit zstd;
+    linkFarm = name: entries:
+      runCommand name { } ''
+        mkdir -p $out
+        ${lib.concatMapStringsSep "\n" (entry: ''
+          cp -rL ${entry.path} $out/${entry.name}
+        '') entries}
+      '';
+  };
+in
+rustPlatform.buildRustPackage {
+  pname = "herdr";
+  version = manifest.package.version;
+
+  src = lib.fileset.toSource {
+    root = ./..;
+    fileset = lib.fileset.intersection (lib.fileset.fromSource (lib.sources.cleanSource ./..)) (
+      lib.fileset.unions [
+        ../assets
+        ../src
+        ../vendor/libghostty-vt
+        ../vendor/libghostty-vt.vendor.json
+        ../build.rs
+        ../Cargo.lock
+        ../Cargo.toml
+      ]
+    );
+  };
+
+  cargoLock.lockFile = ../Cargo.lock;
+
+  nativeBuildInputs = [
+    git
+    pkg-config
+  ];
+
+  env = {
+    LIBGHOSTTY_VT_OPTIMIZE = "ReleaseFast";
+    LIBGHOSTTY_VT_SIMD = "true";
+    LIBGHOSTTY_VT_ZIG_SYSTEM_DIR = zigDeps;
+    ZIG = lib.getExe zig_0_15;
+  };
+
+  preBuild = ''
+    export ZIG_GLOBAL_CACHE_DIR="$TMPDIR/zig-global-cache"
+    export ZIG_LOCAL_CACHE_DIR="$TMPDIR/zig-local-cache"
+  '';
+
+  # Rust tests are covered by the normal CI workflow. The Nix check is
+  # intentionally build-only so it validates packaging inputs without
+  # duplicating the full Rust test suite.
+  doCheck = false;
+
+  meta = {
+    description = "Terminal workspace manager for AI coding agents";
+    homepage = "https://herdr.dev";
+    license = lib.licenses.agpl3Plus;
+    mainProgram = "herdr";
+    platforms = lib.platforms.linux ++ lib.platforms.darwin;
+  };
+}
diff --git a/src/update.rs b/src/update.rs
index f37a9265..2a2776fa 100644
--- a/src/update.rs
+++ b/src/update.rs
@@ -21,6 +21,7 @@ const UPDATE_MANIFEST_URL: &str = "https://herdr.dev/latest.json";
 const HOMEBREW_FORMULA_API_URL: &str = "https://formulae.brew.sh/api/formula/herdr.json";
 const HERDR_UPDATE_COMMAND: &str = "herdr update";
 const HOMEBREW_UPDATE_COMMAND: &str = "brew update && brew upgrade herdr";
+const NIX_UPDATE_COMMAND: &str = "update through Nix";
 const CURRENT_VERSION: &str = env!("CARGO_PKG_VERSION");
 const FAKE_UPDATE_VERSION_ENV: &str = "HERDR_FAKE_UPDATE_VERSION";
 const FAKE_UPDATE_NOTES_VERSION_ENV: &str = "HERDR_FAKE_UPDATE_NOTES_VERSION";
@@ -678,6 +679,8 @@ fn wait_for_server_shutdown(timeout: Duration) -> Result<(), String> {
 pub(crate) fn update_install_command() -> &'static str {
     if is_homebrew_managed_install() {
         HOMEBREW_UPDATE_COMMAND
+    } else if is_nix_managed_install() {
+        NIX_UPDATE_COMMAND
     } else {
         HERDR_UPDATE_COMMAND
     }
@@ -697,6 +700,24 @@ fn is_homebrew_managed_install() -> bool {
         .is_ok_and(|path| is_homebrew_managed_exe_path(&path))
 }
 
+fn is_nix_managed_install() -> bool {
+    let Ok(current_exe) = env::current_exe() else {
+        return false;
+    };
+
+    if is_nix_store_exe_path(&current_exe) {
+        return true;
+    }
+
+    current_exe
+        .canonicalize()
+        .is_ok_and(|path| is_nix_store_exe_path(&path))
+}
+
+fn is_nix_store_exe_path(path: &Path) -> bool {
+    path.starts_with("/nix/store")
+}
+
 fn is_homebrew_managed_exe_path(path: &Path) -> bool {
     homebrew_cellar_keg_root(path).is_some()
 }
@@ -991,6 +1012,12 @@ pub fn self_update() -> Result<Version, String> {
         ));
     }
 
+    if is_nix_managed_install() {
+        return Err(
+            "self-update is disabled for Nix installs; update with `nix profile upgrade` or update the flake input that provides Herdr".into(),
+        );
+    }
+
     if running_inside_herdr() {
         return Err("run `herdr update` outside herdr after detaching from the session".into());
     }
@@ -1075,6 +1102,8 @@ pub fn auto_update(events: tokio::sync::mpsc::Sender<crate::events::AppEvent>) {
         return;
     }
 
+    let nix_managed_install = is_nix_managed_install();
+
     let release = match check_latest() {
         Ok(Some(r)) => r,
         Ok(None) => return,
@@ -1103,9 +1132,15 @@ pub fn auto_update(events: tokio::sync::mpsc::Sender<crate::events::AppEvent>) {
     );
 
     // Notify the TUI — blocking_send is safe from a std::thread
+    let install_command = if nix_managed_install {
+        NIX_UPDATE_COMMAND
+    } else {
+        HERDR_UPDATE_COMMAND
+    };
+
     let _ = events.blocking_send(crate::events::AppEvent::UpdateReady {
         version: release.version.to_string(),
-        install_command: HERDR_UPDATE_COMMAND.to_string(),
+        install_command: install_command.to_string(),
     });
 }
 
@@ -1288,6 +1323,20 @@ mod tests {
     }
 
     #[test]
+    fn nix_store_path_is_detected() {
+        let path = Path::new("/nix/store/abc123-herdr-0.6.1/bin/herdr");
+
+        assert!(is_nix_store_exe_path(path));
+    }
+
+    #[test]
+    fn non_nix_store_path_is_not_detected() {
+        let path = Path::new("/usr/local/bin/herdr");
+
+        assert!(!is_nix_store_exe_path(path));
+    }
+
+    #[test]
     fn parse_homebrew_formula_stable_version_reads_versions_stable() {
         let version = parse_homebrew_formula_stable_version(
             br#"{"versions":{"stable":"0.5.10","head":"HEAD","bottle":true}}"#,