ci: move formatting checks to nix

.circleci/config.yml

@@ -51,6 +51,10 @@ workflows:
           exclude_regex: ".*inheritance_polymorphic.*|.*arrays_member_int0|.*fbstring.*|.*std_string_*|.*multi_arg_tb_.*|.*ignored_a"
 
 executors:
+  nix-docker:
+    docker:
+      - image: nixos/nix:latest
+    resource_class: small
   ubuntu-docker:
     docker:
       - image: ubuntu:jammy
@@ -62,33 +66,12 @@ executors:
 
 jobs:
   lint:
-    executor: ubuntu-docker
+    executor: nix-docker
     steps:
-      - run:
-          name: Install dependencies
-          command: |
-            apt-get update
-            apt-get install -y \
-              clang-format \
-              git \
-              python3-pip
-            # click broke semver with 8.1.0, causing issues for black
-            pip install click==8.0.0 black isort
-          environment:
-            DEBIAN_FRONTEND: noninteractive
       - checkout
       - run:
-          name: clang-format
-          command: |
-            git ls-files '*.cpp' '*.h' | xargs clang-format --fallback-style=Google -i
-            git ls-files '*.py' | xargs black
-            git ls-files '*.py' | xargs isort
-            git diff --exit-code
-      - run:
-          name: python linting
-          command: |
-            black --check --diff test/
-            isort --check --diff test/
+          name: Flake check
+          command: nix --experimental-features 'nix-command flakes' flake check
 
   build:
     # TODO this job could be run in Docker

flake.lock

@@ -0,0 +1,82 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1694529238,
+        "narHash": "sha256-zsNZZGTGnMOf9YpHKJqMSsa0dXbfmxeoJ7xHlrt+xmY=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "ff7b65b44d01cf9ba6a71320833626af21126384",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1696375444,
+        "narHash": "sha256-Sv0ICt/pXfpnFhTGYTsX6lUr1SljnuXWejYTI2ZqHa4=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "81e8f48ebdecf07aab321182011b067aafc78896",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs",
+        "treefmt-nix": "treefmt-nix"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
+    "treefmt-nix": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1695822946,
+        "narHash": "sha256-IQU3fYo0H+oGlqX5YrgZU3VRhbt2Oqe6KmslQKUO4II=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "720bd006d855b08e60664e4683ccddb7a9ff614a",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,30 @@
+{
+  description = "A flake for building Object Introspection.";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+
+    flake-utils.url = "github:numtide/flake-utils";
+
+    treefmt-nix.url = "github:numtide/treefmt-nix";
+    treefmt-nix.inputs.nixpkgs.follows = "nixpkgs";
+  };
+
+  outputs = { self, nixpkgs, flake-utils, treefmt-nix, ... }@inputs:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+        treefmtEval = treefmt-nix.lib.evalModule pkgs (pkgs: {
+          projectRootFile = "flake.nix";
+          settings.global.excludes = [ "./extern/**" ];
+
+          programs.nixfmt.enable = true;
+          programs.clang-format.enable = true;
+          programs.black.enable = true;
+          programs.isort.enable = true;
+        });
+      in {
+        formatter = treefmtEval.config.build.wrapper;
+        checks.formatting = treefmtEval.config.build.check self;
+      });
+}