From 8ea20e5812c26c1f852e5102b64eddce14070e67 Mon Sep 17 00:00:00 2001
From: Zachary Arnaise <121795280+zacharyarnaise@users.noreply.github.com>
Date: Wed, 28 Jan 2026 19:14:44 +0100
Subject: [PATCH] nixos/ly: add support for auto-login

---
 .../modules/services/display-managers/ly.nix  | 35 +++++++++++++++----
 nixos/tests/ly.nix                            | 20 +++++++++++
 2 files changed, 48 insertions(+), 7 deletions(-)

diff --git a/nixos/modules/services/display-managers/ly.nix b/nixos/modules/services/display-managers/ly.nix
index 368a067a4d9a..43292a40149d 100644
--- a/nixos/modules/services/display-managers/ly.nix
+++ b/nixos/modules/services/display-managers/ly.nix
@@ -17,13 +17,14 @@ let
   iniFmt = pkgs.formats.iniWithGlobalSection { };
 
   inherit (lib)
-    concatMapStrings
     attrNames
+    concatMapStrings
     getAttr
     mkIf
     mkOption
     mkEnableOption
     mkPackageOption
+    optionalAttrs
     ;
 
   xserverWrapper = pkgs.writeShellScript "xserver-wrapper" ''
@@ -47,6 +48,11 @@ let
     setup_cmd = dmcfg.sessionData.wrapper;
     brightness_up_cmd = "${lib.getExe pkgs.brightnessctl} -q -n s +10%";
     brightness_down_cmd = "${lib.getExe pkgs.brightnessctl} -q -n s 10%-";
+  }
+  // optionalAttrs dmcfg.autoLogin.enable {
+    auto_login_service = "ly-autologin";
+    auto_login_session = dmcfg.sessionData.autologinSession;
+    auto_login_user = dmcfg.autoLogin.user;
   };
 
   finalConfig = defaultConfig // cfg.settings;
@@ -84,17 +90,32 @@ in
 
     assertions = [
       {
-        assertion = !dmcfg.autoLogin.enable;
+        assertion = dmcfg.autoLogin.enable -> dmcfg.sessionData.autologinSession != null;
         message = ''
-          ly doesn't support auto login.
+          ly auto-login requires that services.displayManager.defaultSession is set.
         '';
       }
     ];
 
-    security.pam.services.ly = {
-      startSession = true;
-      unixAuth = true;
-      enableGnomeKeyring = lib.mkDefault config.services.gnome.gnome-keyring.enable;
+    security.pam.services = {
+      ly = {
+        startSession = true;
+        unixAuth = true;
+        enableGnomeKeyring = lib.mkDefault config.services.gnome.gnome-keyring.enable;
+      };
+    }
+    // optionalAttrs dmcfg.autoLogin.enable {
+      ly-autologin.text = ''
+        auth      requisite pam_nologin.so
+        auth      required  pam_succeed_if.so uid >= 1000 quiet
+        auth      required  pam_permit.so
+
+        account   include   ly
+
+        password  include   ly
+
+        session   include   ly
+      '';
     };
 
     environment = {
diff --git a/nixos/tests/ly.nix b/nixos/tests/ly.nix
index a9c74c5f3ca7..2d9303308001 100644
--- a/nixos/tests/ly.nix
+++ b/nixos/tests/ly.nix
@@ -23,6 +23,18 @@ in
       services.displayManager.defaultSession = "none+icewm";
       services.xserver.windowManager.icewm.enable = true;
     };
+  nodes.machineAutologin =
+    { ... }:
+    lib.attrsets.recursiveUpdate machineBase {
+      services.displayManager.ly.x11Support = true;
+      services.xserver.enable = true;
+      services.displayManager.defaultSession = "none+icewm";
+      services.xserver.windowManager.icewm.enable = true;
+      services.displayManager.autoLogin = {
+        enable = true;
+        user = "alice";
+      };
+    };
   nodes.machineNoX11 =
     { ... }:
     lib.attrsets.recursiveUpdate machineBase {
@@ -83,6 +95,14 @@ in
       machine.sleep(2)
       machine.screenshot("icewm")
 
+      machineAutologin.wait_until_succeeds("getfacl /dev/dri/card0 | grep video")
+      machineAutologin.send_key("ctrl-alt-f1")
+      machineAutologin.wait_for_file("/run/user/${toString user.uid}/lyxauth")
+      machineAutologin.succeed("xauth merge /run/user/${toString user.uid}/lyxauth")
+      machineAutologin.wait_for_window("^IceWM ")
+      machineAutologin.sleep(2)
+      machineAutologin.screenshot("autologin-icewm")
+
       machineNoX11.wait_until_tty_matches("1", "password")
       machineNoX11.send_key("ctrl-alt-f1")
       machineNoX11.sleep(1)