From bc9bb5d4053d40be2c3b7a8bb2f0539137b57c91 Mon Sep 17 00:00:00 2001
From: Johannes Kirschbauer <hsjobeki@gmail.com>
Date: Tue, 15 Apr 2025 17:25:51 +0200
Subject: [PATCH] feat(buildClan): expose {nixosModules,darwinModules} from
 clanInternals

These are the exact same modules that where used internally to construct the corresponding
'nixosConfiguration', 'darwinConfiguration'
They can be externally used, and would yield the same result
Given that you pass the same 'specialArgs'
---
 lib/build-clan/module.nix | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/lib/build-clan/module.nix b/lib/build-clan/module.nix
index 048546aa5..95d0af885 100644
--- a/lib/build-clan/module.nix
+++ b/lib/build-clan/module.nix
@@ -62,6 +62,8 @@ let
   configurations = lib.mapAttrs (
     name: _:
     moduleSystemConstructor.${machineClasses.${name}} {
+      # ATTENTION!: Dont add any modules here.
+      # Add them to 'outputs.moduleForMachine.${name}' instead.
       modules = [ (config.outputs.moduleForMachine.${name} or { }) ];
       specialArgs = {
         inherit clan-core;
@@ -113,10 +115,10 @@ in
         type = lib.types.attrsOf lib.types.deferredModule;
       };
       config.outputs.moduleForMachine = lib.mkMerge [
-        # Create one empty module for each machine such that there is a default for each machine
-        # See: 'staticModules' in the moduleForMachine option
-        # This is only necessary because clan.machines doesn't include all machines
-        # There can other sources: i.e. inventory
+        # Create some modules for each machine
+        # These can depend on the 'name' and
+        # everything that can be derived from the machine 'name'
+        # i.e. by looking up the corresponding information in the 'inventory' or 'clan' submodule
         (lib.mapAttrs (
           name: v:
           (
@@ -173,10 +175,24 @@ in
     ./computed-tags.nix
   ];
 
+  # Ready to use configurations
+  # These are only shallow wrapping the 'nixosModules' or 'darwinModules' with
+  # lib.nixosSystem
   inherit nixosConfigurations;
   inherit darwinConfigurations;
 
   clanInternals = {
+    # Expose reusable modules these can be imported or wrapped or instantiated
+    # - by the user
+    # - by some test frameworks
+    # IMPORTANT!: It is utterly important that we don't add any logic outside of these modules, as it would get tested.
+    nixosModules = lib.filterAttrs (
+      name: _: inventory.machines.${name}.machineClass or "nixos" == "nixos"
+    ) (config.outputs.moduleForMachine);
+    darwinModules = lib.filterAttrs (
+      name: _: inventory.machines.${name}.machineClass or "nixos" == "darwin"
+    ) (config.outputs.moduleForMachine);
+
     moduleSchemas = clan-core.clanLib.modules.getModulesSchema {
       modules = config.inventory.modules;
       # TODO: make this function system agnostic