Feature/treefmt - Integrate treefmt-nix

README.md

@@ -42,6 +42,9 @@ Running ``devenv init`` generates ``devenv.nix``:
   # https://devenv.sh/pre-commit-hooks/
   pre-commit.hooks.shellcheck.enable = true;
 
+  # https://devenv.sh/treefmt/
+  treefmt.programs.nixpkgs-fmt.enable = true;
+
   # https://devenv.sh/processes/
   processes.ping.exec = "ping localhost";
 }

devenv.lock

@@ -155,6 +155,22 @@
         "type": "github"
       }
     },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1718895438,
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "d603719ec6e294f034936c0d0dc06f689d91b6c3",
+        "treeHash": "5431d5da7bc85049065fe5a6ac014ed1d2b9abe4",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "pre-commit-hooks": {
       "inputs": {
         "flake-compat": "flake-compat_2",
@@ -184,7 +200,8 @@
         "devenv": "devenv",
         "nix": "nix",
         "nixpkgs": "nixpkgs",
-        "pre-commit-hooks": "pre-commit-hooks"
+        "pre-commit-hooks": "pre-commit-hooks",
+        "treefmt-nix": "treefmt-nix"
       }
     },
     "systems": {
@@ -201,6 +218,24 @@
         "repo": "default",
         "type": "github"
       }
+    },
+    "treefmt-nix": {
+      "inputs": {
+        "nixpkgs": "nixpkgs_2"
+      },
+      "locked": {
+        "lastModified": 1718522839,
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "68eb1dc333ce82d0ab0c0357363ea17c31ea1f81",
+        "treeHash": "3a739f95f5906aab649d47fe4832696cc9f87de5",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
+      }
     }
   },
   "root": "root",

devenv.nix

@@ -138,12 +138,22 @@
     '';
   };
 
+  #enable tree fmt
+  treefmt = {
+    projectRootFile = "devenv.nix";
+    programs = {
+      nixpkgs-fmt.enable = true;
+      rustfmt.enable = true;
+    };
+  };
+
   pre-commit.hooks = {
-    nixpkgs-fmt.enable = true;
     #shellcheck.enable = true;
     #clippy.enable = true;
-    rustfmt.enable = true;
     #markdownlint.enable = true;
+    treefmt = {
+      enable = true;
+    };
     markdownlint.settings.configuration = {
       MD013 = {
         line_length = 120;

devenv/src/flake.tmpl.nix

@@ -5,6 +5,7 @@
         in {
         pre-commit-hooks.url = "github:cachix/pre-commit-hooks.nix";
       pre-commit-hooks.inputs.nixpkgs.follows = "nixpkgs";
+      treefmt-nix.url = "github:numtide/treefmt-nix";
       nixpkgs.url = "github:cachix/devenv-nixpkgs/rolling";
       devenv.url = "github:cachix/devenv?dir=src/modules";
       } // (if builtins.pathExists (devenv_dotfile + "/flake.json")

docs/treefmt.md

@@ -0,0 +1,73 @@
+# `devenv` Integration for [treefmt](https://treefmt.com/) via [treefmt-nix](https://github.com/numtide/treefmt-nix)
+
+## Set up
+
+Check the available integrations in [the list of all available integrations](reference/options.md#treefmt).
+
+Add your desired integration to your `devenv.nix` file. For example, the following code would enable `treefmt` with the `nixpkgs-fmt` and `rustfmt` integrations:
+
+```nix
+{ inputs, ... }:
+
+{
+  treefmt = {
+    projectRootFile = "devenv.nix";
+    programs = {
+        nixpkgs-fmt.enable = true;
+        rustfmt.enable = true;
+    };
+  };
+}
+```
+
+### In Action:
+
+```shell-session
+$ devenv shell
+Building shell ...
+Entering shell ...
+
+treefmt # This would run treefmt on all files.
+```
+
+## Additional Devenv Integrations
+
+### Pre-commit Hooks
+
+If you would like to enable `treefmt` in your pre-commit hooks, simply add:
+
+```nix
+{ inputs, ... }:
+
+{
+  pre-commit.hooks = {
+    treefmt.enable = true;
+  };
+}
+```
+
+This will enable `treefmt` hooks and automatically change the default package to the one you have defined in your `devenv`.
+
+## Using a Custom Formatter
+
+It is also possible to use custom formatters with `treefmt-nix`. For example, the following custom formatter formats JSON files using `yq-go`:
+
+```nix
+{
+  treefmt.settings.formatter = {
+    "yq-json" = {
+      command = "${pkgs.bash}/bin/bash";
+      options = [
+        "-euc"
+        ''
+          for file in "$@"; do
+            ${lib.getExe yq-go} -i --output-format=json $file
+          done
+        ''
+        "--" # bash swallows the second argument when using -c
+      ];
+      includes = [ "*.json" ];
+    };
+  };
+}
+```

flake.nix

@@ -14,6 +14,12 @@
       flake-compat.follows = "flake-compat";
     };
   };
+  inputs.treefmt-nix = {
+    url = "github:numtide/treefmt-nix";
+    inputs = {
+      nixpkgs.follows = "nixpkgs";
+    };
+  };
   inputs.flake-compat = {
     url = "github:edolstra/flake-compat";
     flake = false;
@@ -35,7 +41,7 @@
   };
 
 
-  outputs = { self, nixpkgs, pre-commit-hooks, nix, ... }@inputs:
+  outputs = { self, nixpkgs, pre-commit-hooks, treefmt-nix, nix, ... }@inputs:
     let
       systems = [ "x86_64-linux" "i686-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin" ];
       forAllSystems = f: builtins.listToAttrs (map (name: { inherit name; value = f name; }) systems);
@@ -49,11 +55,12 @@
               ./src/modules/top-level.nix
               { devenv.warnOnNewVersion = false; }
             ];
-            specialArgs = { inherit pre-commit-hooks pkgs inputs; };
+            specialArgs = { inherit pre-commit-hooks treefmt-nix pkgs inputs; };
           };
           sources = [
             { name = "${self}"; url = "https://github.com/cachix/devenv/blob/main"; }
             { name = "${pre-commit-hooks}"; url = "https://github.com/cachix/pre-commit-hooks.nix/blob/master"; }
+            { name = "${treefmt-nix}"; url = "https://github.com/numtide/treefmt-nix/blob/main"; }
           ];
           rewriteSource = decl:
             let

src/modules/integrations/treefmt.nix

@@ -0,0 +1,21 @@
+{ pkgs, self, lib, inputs, config, ... }: {
+
+  options.treefmt = lib.mkOption {
+    type = lib.types.submoduleWith {
+      modules = inputs.treefmt-nix.lib.submodule-modules;
+      specialArgs = { inherit pkgs; };
+      shorthandOnlyDefinesConfig = true;
+    };
+    default = { };
+    description = "Integration of https://github.com/numtide/treefmt-nix";
+  };
+
+  config = lib.mkIf ((lib.filterAttrs (id: value: value.enable) config.treefmt.programs) != { }) {
+    packages = [
+      config.treefmt.build.wrapper
+    ];
+
+    #automatically add treefmt-nix to pre-commit if the user enables it.
+    pre-commit.hooks.treefmt.package = lib.mkForce config.treefmt.build.wrapper;
+  };
+}