feat: add flake compat

Signed-off-by: Brian McGee <brian@bmcgee.ie>

default.nix

@@ -0,0 +1,17 @@
+# This file provides backward compatibility to nix < 2.4 clients
+{system ? builtins.currentSystem}: let
+  lock = builtins.fromJSON (builtins.readFile ./flake.lock);
+
+  inherit (lock.nodes.flake-compat.locked) owner repo rev narHash;
+
+  flake-compat = fetchTarball {
+    url = "https://github.com/${owner}/${repo}/archive/${rev}.tar.gz";
+    sha256 = narHash;
+  };
+
+  flake = import flake-compat {
+    inherit system;
+    src = ./.;
+  };
+in
+  flake.defaultNix

docs/faq.md

@@ -2,19 +2,19 @@
 
 ## How does treefmt function?
 
-`Treefmt` traverses all your project's folders, maps files to specific code formatters, and formats the code 
+`Treefmt` traverses all your project's folders, maps files to specific code formatters, and formats the code
 accordingly. Other tools also traverse the filesystem, but not necessarily starting from the root of the project.
 
-Contrary to other formatters, `treefmt` doesn't preview the changes before writing them to a file. If you want to view 
+Contrary to other formatters, `treefmt` doesn't preview the changes before writing them to a file. If you want to view
-the changes, you can always check the diff in your version control (we assume that your project is checked into a 
+the changes, you can always check the diff in your version control (we assume that your project is checked into a
-version control system). 
+version control system).
 
-You can also rely on version control if errors were introduced into your code as a result of disruptions in the 
+You can also rely on version control if errors were introduced into your code as a result of disruptions in the
 formatter's work.
 
 ## How is the cache organized?
 
-At the moment, the cache is a [BoltDB] database file in which file paths are mapped to `mtimes`. 
+At the moment, the cache is a [BoltDB] database file in which file paths are mapped to `mtimes`.
 
 The file is located in:
 
@@ -22,7 +22,7 @@ The file is located in:
 ~/.cache/treefmt/eval-cache/<hash-of-the-treefmt.toml-path>.db
 ```
 
-At the end of each run, the database is updated with the last formatting time entries. In this way, we can 
+At the end of each run, the database is updated with the last formatting time entries. In this way, we can
 compare the last change time of the file to the last formatting time, and figure out which files need re-formatting.
 
-[BoltDB]: https://github.com/etcd-io/bbolt
+[BoltDB]: https://github.com/etcd-io/bbolt

flake.lock

@@ -21,6 +21,21 @@
         "type": "github"
       }
     },
+    "flake-compat": {
+      "locked": {
+        "lastModified": 1688025799,
+        "narHash": "sha256-ktpB4dRtnksm9F5WawoIkEneh1nrEvuxb5lJFt1iOyw=",
+        "owner": "nix-community",
+        "repo": "flake-compat",
+        "rev": "8bf105319d44f6b9f0d764efa4fdef9f1cc9ba1c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
     "flake-parts": {
       "inputs": {
         "nixpkgs-lib": "nixpkgs-lib"
@@ -163,6 +178,7 @@
     "root": {
       "inputs": {
         "devshell": "devshell",
+        "flake-compat": "flake-compat",
         "flake-parts": "flake-parts",
         "flake-root": "flake-root",
         "gomod2nix": "gomod2nix",

flake.nix

@@ -3,7 +3,6 @@
 
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
-
     flake-parts.url = "github:hercules-ci/flake-parts";
     flake-root.url = "github:srid/flake-root";
     treefmt-nix = {
@@ -19,8 +18,8 @@
       url = "github:nix-community/gomod2nix";
       inputs.nixpkgs.follows = "nixpkgs";
     };
-
     nix-filter.url = "github:numtide/nix-filter";
+    flake-compat.url = "github:nix-community/flake-compat";
   };
 
   outputs = inputs @ {flake-parts, ...}:

shell.nix

@@ -0,0 +1,17 @@
+# This file provides backward compatibility to nix < 2.4 clients
+{system ? builtins.currentSystem}: let
+  lock = builtins.fromJSON (builtins.readFile ./flake.lock);
+
+  inherit (lock.nodes.flake-compat.locked) owner repo rev narHash;
+
+  flake-compat = fetchTarball {
+    url = "https://github.com/${owner}/${repo}/archive/${rev}.tar.gz";
+    sha256 = narHash;
+  };
+
+  flake = import flake-compat {
+    inherit system;
+    src = ./.;
+  };
+in
+  flake.shellNix