feat: more idomatic template flake.nix

templates/app/flake.nix

@@ -7,38 +7,60 @@
     poetry2nix = {
       url = "github:nix-community/poetry2nix";
       inputs.nixpkgs.follows = "nixpkgs";
+      inputs.flake-utils.follows = "flake-utils";
+      inputs.systems.follows = "flake-utils";
     };
   };
 
   outputs = { self, nixpkgs, flake-utils, poetry2nix }:
     flake-utils.lib.eachDefaultSystem (system:
       let
         # see https://github.com/nix-community/poetry2nix/tree/master#api for more functions and examples.
-        pkgs = nixpkgs.legacyPackages.${system};
-        inherit (poetry2nix.lib.mkPoetry2Nix { inherit pkgs; }) mkPoetryApplication;
-      in
-      {
-        packages = {
-          myapp = mkPoetryApplication { projectDir = self; };
-          default = self.packages.${system}.myapp;
+        myapp = { poetry2nix, lib }: poetry2nix.mkPoetryApplication {
+          projectDir = self;
+          overrides = poetry2nix.overrides.withDefaults (final: super:
+            lib.mapAttrs
+              (attr: systems: super.${attr}.overridePythonAttrs
+                (old: {
+                  nativeBuildInputs = (old.nativeBuildInputs or [ ]) ++ map (a: final.${a}) systems;
+                }))
+              {
+                x25519 = [ "setuptools" ];
+              }
+          );
         };
-
-        # Shell for app dependencies.
-        #
-        #     nix develop
-        #
-        # Use this shell for developing your app.
-        devShells.default = pkgs.mkShell {
-          inputsFrom = [ self.packages.${system}.myapp ];
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = [
+            poetry2nix.overlays.default
+            (final: _: {
+              myapp = final.callPackage myapp { };
+            })
+          ];
         };
+      in
+      {
+        packages.default = pkgs.myapp;
+        devShells = {
+          # Shell for app dependencies.
+          #
+          #     nix develop
+          #
+          # Use this shell for developing your app.
+          default = pkgs.mkShell {
+            inputsFrom = [ pkgs.myapp ];
+          };
 
-        # Shell for poetry.
-        #
-        #     nix develop .#poetry
-        #
-        # Use this shell for changes to pyproject.toml and poetry.lock.
-        devShells.poetry = pkgs.mkShell {
-          packages = [ pkgs.poetry ];
+          # Shell for poetry.
+          #
+          #     nix develop .#poetry
+          #
+          # Use this shell for changes to pyproject.toml and poetry.lock.
+          poetry = pkgs.mkShell {
+            packages = [ pkgs.poetry ];
+          };
         };
-      });
+        legacyPackages = pkgs;
+      }
+    );
 }