maint: Move treefmt to dev partition

Moves treefmt-nix input and configuration from the main flake to the
dev partition, since it's a development-only dependency. Also switches
pre-commit hooks from individual formatter hooks to the unified treefmt
hook for better consistency.

dev/flake-module.nix

@@ -6,6 +6,7 @@
   imports = [
     inputs.pre-commit-hooks-nix.flakeModule
     inputs.hercules-ci-effects.flakeModule
+    inputs.treefmt-nix.flakeModule
   ];
   perSystem =
     {
@@ -17,7 +18,20 @@
     {
       nix-bindings-rust.nixPackage = inputs'.nix.packages.default;
 
-      pre-commit.settings.hooks.nixfmt-rfc-style.enable = true;
+      treefmt = {
+        # Used to find the project root
+        projectRootFile = "flake.lock";
+
+        programs.rustfmt = {
+          enable = true;
+          edition = "2021";
+        };
+        programs.nixfmt.enable = true;
+        programs.deadnix.enable = true;
+        #programs.clang-format.enable = true;
+      };
+
+      pre-commit.settings.hooks.treefmt.enable = true;
       # Temporarily disable rustfmt due to configuration issues
       # pre-commit.settings.hooks.rustfmt.enable = true;
       pre-commit.settings.settings.rust.cargoManifestPath = "./Cargo.toml";

dev/flake.lock

@@ -36,27 +36,6 @@
         "type": "indirect"
       }
     },
-    "flake-parts_2": {
-      "inputs": {
-        "nixpkgs-lib": [
-          "nix-unit",
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1754487366,
-        "narHash": "sha256-pHYj8gUBapuUzKV/kN/tR3Zvqc7o6gdFB9XKXIp1SQ8=",
-        "owner": "hercules-ci",
-        "repo": "flake-parts",
-        "rev": "af66ad14b28a127c5c0f3bbb298218fc63528a18",
-        "type": "github"
-      },
-      "original": {
-        "owner": "hercules-ci",
-        "repo": "flake-parts",
-        "type": "github"
-      }
-    },
     "gitignore": {
       "inputs": {
         "nixpkgs": [
@@ -97,26 +76,6 @@
         "type": "github"
       }
     },
-    "nix-unit": {
-      "inputs": {
-        "flake-parts": "flake-parts_2",
-        "nixpkgs": "nixpkgs_2",
-        "treefmt-nix": "treefmt-nix"
-      },
-      "locked": {
-        "lastModified": 1754985033,
-        "narHash": "sha256-OLaoMtlNL5AvYuaQ5P4p7riy7M9J8XpFdWKpD5RzQfU=",
-        "owner": "nix-community",
-        "repo": "nix-unit",
-        "rev": "388045c7bee5a2617cca8e94444bea1862df19ac",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-community",
-        "repo": "nix-unit",
-        "type": "github"
-      }
-    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1755027561,
@@ -133,22 +92,6 @@
         "type": "github"
       }
     },
-    "nixpkgs_2": {
-      "locked": {
-        "lastModified": 1754800730,
-        "narHash": "sha256-HfVZCXic9XLBgybP0318ym3cDnGwBs/+H5MgxFVYF4I=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "641d909c4a7538f1539da9240dedb1755c907e40",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixpkgs-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
     "pre-commit-hooks-nix": {
       "inputs": {
         "flake-compat": "flake-compat",
@@ -172,23 +115,20 @@
     "root": {
       "inputs": {
         "hercules-ci-effects": "hercules-ci-effects",
-        "nix-unit": "nix-unit",
+        "pre-commit-hooks-nix": "pre-commit-hooks-nix",
-        "pre-commit-hooks-nix": "pre-commit-hooks-nix"
+        "treefmt-nix": "treefmt-nix"
       }
     },
     "treefmt-nix": {
       "inputs": {
-        "nixpkgs": [
+        "nixpkgs": []
-          "nix-unit",
-          "nixpkgs"
-        ]
       },
       "locked": {
-        "lastModified": 1754847726,
+        "lastModified": 1762938485,
-        "narHash": "sha256-2vX8QjO5lRsDbNYvN9hVHXLU6oMl+V/PsmIiJREG4rE=",
+        "narHash": "sha256-AlEObg0syDl+Spi4LsZIBrjw+snSVU4T8MOeuZJUJjM=",
         "owner": "numtide",
         "repo": "treefmt-nix",
-        "rev": "7d81f6fb2e19bf84f1c65135d1060d829fae2408",
+        "rev": "5b4ee75aeefd1e2d5a1cc43cf6ba65eba75e83e4",
         "type": "github"
       },
       "original": {

dev/flake.nix

@@ -4,6 +4,8 @@
     pre-commit-hooks-nix.url = "github:cachix/pre-commit-hooks.nix";
     pre-commit-hooks-nix.inputs.nixpkgs.follows = "";
     hercules-ci-effects.url = "github:hercules-ci/hercules-ci-effects";
+    treefmt-nix.url = "github:numtide/treefmt-nix";
+    treefmt-nix.inputs.nixpkgs.follows = "";
   };
   outputs = { ... }: { };
 }

flake.lock

@@ -344,8 +344,7 @@
         "flake-parts": "flake-parts",
         "nix": "nix",
         "nix-cargo-integration": "nix-cargo-integration",
-        "nixpkgs": "nixpkgs",
+        "nixpkgs": "nixpkgs"
-        "treefmt-nix": "treefmt-nix"
       }
     },
     "rust-overlay": {
@@ -412,26 +411,6 @@
         "repo": "treefmt-nix",
         "type": "github"
       }
-    },
-    "treefmt-nix": {
-      "inputs": {
-        "nixpkgs": [
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1762938485,
-        "narHash": "sha256-AlEObg0syDl+Spi4LsZIBrjw+snSVU4T8MOeuZJUJjM=",
-        "owner": "numtide",
-        "repo": "treefmt-nix",
-        "rev": "5b4ee75aeefd1e2d5a1cc43cf6ba65eba75e83e4",
-        "type": "github"
-      },
-      "original": {
-        "owner": "numtide",
-        "repo": "treefmt-nix",
-        "type": "github"
-      }
     }
   },
   "root": "root",

flake.nix

@@ -8,8 +8,6 @@
     nix-cargo-integration.url = "github:yusdacra/nix-cargo-integration";
     nix-cargo-integration.inputs.nixpkgs.follows = "nixpkgs";
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-    treefmt-nix.url = "github:numtide/treefmt-nix";
-    treefmt-nix.inputs.nixpkgs.follows = "nixpkgs";
   };
 
   outputs =
@@ -164,7 +162,6 @@
           inputs.nix-cargo-integration.flakeModule
           inputs.flake-parts.flakeModules.partitions
           inputs.flake-parts.flakeModules.modules
-          inputs.treefmt-nix.flakeModule
           # dogfood
           flake-parts-modules.tested
           ./nci.nix
@@ -182,19 +179,6 @@
           }:
           {
             packages.nix = inputs'.nix.packages.nix;
-
-            treefmt = {
-              # Used to find the project root
-              projectRootFile = "flake.lock";
-
-              programs.rustfmt = {
-                enable = true;
-                edition = "2021";
-              };
-              programs.nixfmt.enable = true;
-              programs.deadnix.enable = true;
-              #programs.clang-format.enable = true;
-            };
           };
 
         partitionedAttrs.devShells = "dev";