Get rid of niv and test support for nixos-22.05

.github/workflows/ci.yaml

@@ -24,9 +24,6 @@ jobs:
     steps:
     - uses: actions/checkout@v3
     - uses: cachix/install-nix-action@v18
-      with:
-          extra_nix_config: |
-            experimental-features = nix-command flakes
     - uses: cachix/cachix-action@v12
       with:
         name: pre-commit-hooks

default.nix

@@ -1,4 +1,10 @@
-let
-  pkgs = import ./nix { };
-in
-pkgs.packages // pkgs.checks // { inherit (pkgs) run; }
+(import
+  (
+    let lock = builtins.fromJSON (builtins.readFile ./flake.lock); in
+    fetchTarball {
+      url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+      sha256 = lock.nodes.flake-compat.locked.narHash;
+    }
+  )
+  { src = ./.; }
+).defaultNix.lib.${builtins.currentSystem}

flake.nix

@@ -1,9 +1,16 @@
 {
   description = "Seamless integration of https://pre-commit.com git hooks with Nix.";
 
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  inputs.nixpkgs-stable.url = "github:NixOS/nixpkgs/nixos-22.05";
   inputs.flake-utils.url = "github:numtide/flake-utils";
+  inputs.flake-compat = {
+    url = "github:edolstra/flake-compat";
+    flake = false;
+  };
+  inputs.gitignore.url = "github:hercules-ci/gitignore.nix";
 
-  outputs = { self, nixpkgs, flake-utils }:
+  outputs = { self, nixpkgs, flake-utils, gitignore, nixpkgs-stable, ... }:
     let
       defaultSystems = [
         "aarch64-linux"
@@ -24,14 +31,19 @@
     }
     // flake-utils.lib.eachSystem defaultSystems (system:
       let
-        exposed = import ./nix { nixpkgs = nixpkgs; inherit system; gitignore-nix-src = null; isFlakes = true; };
+        exposed = import ./nix { nixpkgs = nixpkgs; inherit system; gitignore-nix-src = gitignore; isFlakes = true; };
+        exposed-stable = import ./nix { nixpkgs = nixpkgs-stable; inherit system; gitignore-nix-src = gitignore; isFlakes = true; };
       in
       {
         packages = exposed.packages;
 
         defaultPackage = exposed.packages.pre-commit;
 
-        checks = exposed.checks;
+        devShell = nixpkgs.legacyPackages.${system}.mkShell {
+          inherit (exposed.checks.pre-commit-check) shellHook;
+        };
+
+        checks = exposed.checks // (builtins.removeAttrs exposed-stable.checks [ "revive" "purs-tidy" ]);
 
         lib = { inherit (exposed) run; };
       }

nix/default.nix

@@ -1,7 +1,6 @@
-{ sources ? import ./sources.nix
-, system ? builtins.currentSystem
-, nixpkgs ? sources.nixpkgs
-, gitignore-nix-src ? sources."gitignore.nix"
+{ system ? builtins.currentSystem
+, nixpkgs
+, gitignore-nix-src
 , isFlakes ? false
 }:
 let
@@ -25,10 +24,6 @@ let
             shellcheck.enable = true;
             nixpkgs-fmt.enable = true;
           };
-          excludes = [
-            # autogenerated by niv
-            "nix/sources.nix$"
-          ];
         };
       };
     };

nix/run.nix

@@ -24,7 +24,7 @@ let
               } // (if isFlakes
               then { rootSrc = src; }
               else {
-                rootSrc = (import gitignore-nix-src { inherit (pkgs) lib; }).gitignoreSource src;
+                rootSrc = gitignore-nix-src.lib.gitignoreSource src;
               });
           }
         ];

nix/tools.nix

@@ -21,7 +21,6 @@
 , html-tidy
 , hunspell
 , luaPackages
-, niv
 , mdsh
 , nix-linter
 , nixfmt
@@ -40,7 +39,7 @@
 , writeScript
 , writeText
 , go
-, revive
+, revive ? null
 }:
 
 {
@@ -49,8 +48,9 @@
   # TODO: these two should be statically compiled
   inherit (haskellPackages) brittany fourmolu;
   inherit (luaPackages) luacheck;
-  inherit (nodePackages) eslint markdownlint-cli prettier purs-tidy;
+  inherit (nodePackages) eslint markdownlint-cli prettier;
   inherit (python39Packages) ansible-lint yamllint;
+  purs-tidy = nodePackages.purs-tidy or null;
   cabal2nix-dir = callPackage ./cabal2nix-dir { };
   hpack-dir = callPackage ./hpack-dir { };
   hunspell = callPackage ./hunspell { };

shell.nix

@@ -1,6 +1,10 @@
-with { pkgs = import ./nix { }; };
-
-pkgs.mkShell {
-  buildInputs = [ pkgs.niv ];
-  inherit ((import ./.).pre-commit-check) shellHook;
-}
+(import
+  (
+    let lock = builtins.fromJSON (builtins.readFile ./flake.lock); in
+    fetchTarball {
+      url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+      sha256 = lock.nodes.flake-compat.locked.narHash;
+    }
+  )
+  { src = ./.; }
+).shellNix