packages: implement shadows

packages/part.nix

@@ -9,6 +9,7 @@ in {
     ./projects.nix
     ./patched-inputs.nix
     ./catalog
+    ./shadows.nix
   ];
   perSystem = { pkgs, self', system, ... }: let
     patched-derivations = import ./patched-derivations.nix (pkgs // { flakePackages = self'.packages; });

packages/shadows.nix

@@ -0,0 +1,19 @@
+{ lib, ... }:
+
+{
+  perSystem = { inputs', self', ... }: {
+    # much like overlays, shadows can *shadow* packages in nixpkgs
+    # unlike overlays, shadows don't cause a nixpkgs re-evaluation
+    # this is a hack for dealing with poorly written NixOS modules
+    # that don't provide a `package` option to perform overrides
+
+    options.shadows = lib.mkOption {
+      type = with lib.types; lazyAttrsOf package;
+      default = {
+        inherit (self'.packages)
+          kanidm
+        ;
+      };
+    };
+  };
+}