From 318186e868998a8e055b74a072c90fe2b5a3e11d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sergio=20Migu=C3=A9ns=20Iglesias?= <sergio@lony.xyz>
Date: Tue, 9 Jun 2026 09:34:12 +0200
Subject: [PATCH] feat: add batteries.user-modules

Works exactly like batteries.host-modules but in reverse, allowing
`host.class`es from the user aspect tree to be projected into onto hosts
that include it.
---
 modules/aspects/batteries/user-aspects.nix | 30 ++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 modules/aspects/batteries/user-aspects.nix

diff --git a/modules/aspects/batteries/user-aspects.nix b/modules/aspects/batteries/user-aspects.nix
new file mode 100644
index 000000000..a8d038456
--- /dev/null
+++ b/modules/aspects/batteries/user-aspects.nix
@@ -0,0 +1,30 @@
+{ den, lib, ... }:
+let
+  description = ''
+    Projects all `host.class`es like `nixos` from the user's aspect tree onto
+    hosts that opt in. Requires the fx pipeline.
+
+    ## Usage
+
+      den.aspects.igloo.includes = [ den.batteries.user-aspects ];
+
+    Any user aspect that defines a `host.class` key will have that config
+    forwarded to the hosts's evaluation.
+  '';
+
+  from-user =
+    { host, user, ... }: [ (den.lib.policy.spawn { classes = [ host.class ]; }) ];
+in
+{
+  den.batteries.user-aspects = {
+    name = "user-aspects";
+    inherit description;
+    includes = [
+      {
+        __isPolicy = true;
+        name = "user-aspects-project";
+        fn = from-user;
+      }
+    ];
+  };
+}