add flake versions

1 files changed, 15 insertions, 3 deletions

diff --git a/flake.nix b/flake.nix
index 204898c..191c5fb 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,7 +2,20 @@
   # WARNING this is very much still experimental.
   description = "A collection of darwin modules";
 
-  outputs = { self, nixpkgs }: {
+  outputs = { self, nixpkgs }:
+  let
+    versionsModule = { lib, ... }: {
+      _file = ./flake.nix;
+      config = {
+        system.darwinVersionSuffix = ".${nixpkgs.shortRev or "dirty"}";
+        system.darwinRevision = lib.mkIf (self ? rev) self.rev;
+
+        system.nixpkgsVersionSuffix = ".${lib.substring 0 8 (nixpkgs.lastModifiedDate or nixpkgs.lastModified or "19700101")}.${nixpkgs.shortRev or "dirty"}";
+        system.nixpkgsRevision = lib.mkIf (nixpkgs ? rev) nixpkgs.rev;
+      };
+    };
+  in
+  {
 
     lib = {
       # TODO handle multiple architectures.
@@ -10,8 +23,7 @@
 
       darwinSystem = { modules, inputs ? {}, ... }@args: self.lib.evalConfig (args // {
         inputs = { inherit nixpkgs; darwin = self; } // inputs;
-        modules = modules ++ [
-        ];
+        modules = modules ++ [ versionsModule ];
       });
     };