From a2d119e73b278a662d7a1f2c1052509ca0c2c5fb Mon Sep 17 00:00:00 2001
From: Harry Hornbacher <dev@harry-hornbacher.de>
Date: Thu, 6 Aug 2026 12:58:55 +0200
Subject: [PATCH] add a nix flake for building and installing faff

- build with rustPlatform.buildRustPackage using the vendored Cargo.lock
- wrap the binary so jj and wezterm are on PATH at runtime; claude still
  comes from the interactive session (spawned inside a wezterm pane)
- skip the jj-dependent test suite in the sandboxed build
- expose packages.default, apps.default, and a dev shell with the rust
  toolchain + jj + wezterm
- read name and version from Cargo.toml
- document nix usage in the README
---
 .gitignore |  1 +
 README.md  | 15 +++++++++++
 flake.lock | 61 +++++++++++++++++++++++++++++++++++++++++
 flake.nix  | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 156 insertions(+)
 create mode 100644 flake.lock
 create mode 100644 flake.nix

diff --git a/.gitignore b/.gitignore
index d81f12e..8807164 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 /target
 /.idea
+/result
diff --git a/README.md b/README.md
index 999fb8e..200de90 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,21 @@ cargo test              # 115 tests; the workspace integration tests shell out t
 cargo clippy --all-targets
 ```
 
+## Nix
+
+A flake is provided. It builds faff and wraps the binary so `jj` and `wezterm` are on
+`PATH` at runtime (`claude` still comes from your interactive session, since faff spawns it
+inside a WezTerm pane).
+
+```sh
+nix run github:Jezza/faff              # run without installing
+nix profile install github:Jezza/faff  # install into your profile
+nix develop                            # dev shell with the toolchain + jj + wezterm
+```
+
+To install declaratively, add the flake as an input and reference
+`faff.packages.${system}.default`.
+
 ## Usage
 
 From your repo root, inside WezTerm:
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..5825cc2
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1785967620,
+        "narHash": "sha256-IItrdb7Puk05RqOBWZYFC5X6Wl1sJmCfh5MWVHw5iMM=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "b7c2ada94fe99c15b0dbcf4d11fd7850b957a436",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..e9d918d
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,79 @@
+{
+  description = "faff — a TUI for running several Claude Code agents in parallel on one repo";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    flake-utils,
+  }:
+    flake-utils.lib.eachDefaultSystem (
+      system: let
+        pkgs = import nixpkgs {inherit system;};
+
+        # Runtime dependencies faff shells out to by bare name. jj drives the
+        # workspaces and wezterm drives the panes. `claude` is intentionally NOT
+        # here: faff spawns it via `wezterm cli spawn -- claude ...`, so it runs
+        # in the user's interactive shell inside the pane, not from faff's PATH.
+        runtimeDeps = [
+          pkgs.jujutsu # provides `jj`
+          pkgs.wezterm # provides `wezterm`
+        ];
+
+        cargoToml = pkgs.lib.importTOML ./Cargo.toml;
+
+        faff = pkgs.rustPlatform.buildRustPackage {
+          pname = cargoToml.package.name;
+          version = cargoToml.package.version;
+
+          src = self;
+
+          cargoLock.lockFile = ./Cargo.lock;
+
+          nativeBuildInputs = [pkgs.makeWrapper];
+
+          # rusqlite's `bundled` feature compiles SQLite from C; the stdenv cc
+          # covers that, no extra buildInputs needed.
+
+          # The test suite (115 tests) shells out to a real `jj`, which is not
+          # available in the build sandbox, so skip it during the Nix build.
+          doCheck = false;
+
+          postInstall = ''
+            wrapProgram $out/bin/faff \
+              --prefix PATH : ${pkgs.lib.makeBinPath runtimeDeps}
+          '';
+
+          meta = {
+            description = "TUI for running several Claude Code agents in parallel on one repo, each in its own jj workspace and WezTerm pane";
+            homepage = "https://github.com/Jezza/faff";
+            mainProgram = "faff";
+          };
+        };
+      in {
+        packages.default = faff;
+        packages.faff = faff;
+
+        apps.default = {
+          type = "app";
+          program = "${faff}/bin/faff";
+        };
+
+        devShells.default = pkgs.mkShell {
+          inputsFrom = [faff];
+          packages =
+            runtimeDeps
+            ++ [
+              pkgs.cargo
+              pkgs.rustc
+              pkgs.clippy
+              pkgs.rustfmt
+            ];
+        };
+      }
+    );
+}