strictly disable overlays (#17)

Author: DavHau

mach_nix/generators/overlay_generator.py

@@ -49,7 +49,7 @@ def _gen_imports(self):
                 url = "https://github.com/nixos/nixpkgs/tarball/{self.nixpkgs_commit}";
                 sha256 = "{self.nixpkgs_tarball_sha256}";
               }};
-              pkgs = import nixpkgs_src {{ config = {{}}; }};
+              pkgs = import nixpkgs_src {{ config = {{}}; overlays = []; }};
               python = pkgs.{self.py_ver_nix};
             """
         return unindent(out, 12)
@@ -171,7 +171,7 @@ def _gen_python_env(self, pkgs: Dict[str, ResolvedPkg]):
         python_with_packages = f"""
             in
             
-            with import nixpkgs_src {{ overlays = [ overlay ]; }};
+            with import nixpkgs_src {{ config = {{}}; overlays = [ overlay ]; }};
             
             {self.py_ver_nix}.withPackages (ps: with ps; [
               {pkg_names.rstrip()}

mach_nix/nix/expression.nix

@@ -11,13 +11,13 @@
 }:
 let
   nixpkgs_src = (import ./nixpkgs-src.nix).stable;
-  pkgs = import nixpkgs_src { config = {}; };
+  pkgs = import nixpkgs_src { config = {}; overlays = []; };
   target_nixpkgs_src = builtins.fetchTarball {
     name = "nixpkgs";
     url = "https://github.com/nixos/nixpkgs/tarball/${nixpkgs_commit}";
     sha256 = "${nixpkgs_tarball_sha256}";
   };
-  target_pkgs = import target_nixpkgs_src { config = {}; };
+  target_pkgs = import target_nixpkgs_src { config = {}; overlays = []; };
   target_python = target_pkgs."${python_attr}";
   nixpkgs_json = import ./nixpkgs-json.nix { pkgs = target_pkgs; python = target_python; };
   builder_python = pkgs.python37.withPackages(ps: