nix(chore): set nixpkgs to nixos-26.05, update flake.lock (#495)

fixes #492
Co-authored-by: KristijanZic <kristijan.zic@10x.engineering>

flake.lock

@@ -2,16 +2,16 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1772963539,
+        "lastModified": 1788405554,
-        "narHash": "sha256-9jVDGZnvCckTGdYT53d/EfznygLskyLQXYwJLKMPsZs=",
+        "narHash": "sha256-r2f1oUwixlgq9zOdYLqJLfS/lWBT60/IITjhTKI59JU=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "9dcb002ca1690658be4a04645215baea8b95f31d",
+        "rev": "a5cc6f2c37bf518436dc8d1c288ccd0c43c2f4c4",
         "type": "github"
       },
       "original": {
         "owner": "nixos",
-        "ref": "nixos-unstable",
+        "ref": "nixos-26.05",
         "repo": "nixpkgs",
         "type": "github"
       }
@@ -29,11 +29,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1773025773,
+        "lastModified": 1788505699,
-        "narHash": "sha256-Wik8+xApNfldpUFjPmJkPdg0RrvUPSWGIZis+A/0N1w=",
+        "narHash": "sha256-PSPDCdbEBEbSDCWcqv5GkbyD2ACQ9Diz6vmEbWdy4dM=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "3c06fdbbd36ff60386a1e590ee0cd52dcd1892bf",
+        "rev": "9eccf73c5b810052f08aa77ae0548c383259f17f",
         "type": "github"
       },
       "original": {

flake.nix

@@ -1,7 +1,8 @@
 {
   description = "Nix Flake for lan-mouse";
   inputs = {
-    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+    # 26.05 used here to keep allowing builds on x86_64-darwin, bump this to unstable once they deprecate 26.05
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-26.05";
     rust-overlay = {
       url = "github:oxalica/rust-overlay";
       inputs.nixpkgs.follows = "nixpkgs";
@@ -30,7 +31,24 @@
             let
               pkgs = import nixpkgs {
                 inherit system;
-                overlays = [ rust-overlay.overlays.default ];
+                overlays = [
+                  rust-overlay.overlays.default
+
+                  #NOTE: appstream's meson build injects the literal string
+                  # "none required" into linker flags on 'aarch64-darwin', causing clang to fail.
+                  # remove this overlay once we bump nixpkgs to unstable branch
+                  (
+                    final: prev:
+                    lib.optionalAttrs prev.stdenv.hostPlatform.isDarwin {
+                      appstream = prev.appstream.overrideAttrs (old: {
+                        postConfigure = (old.postConfigure or "") + ''
+                          substituteInPlace build.ninja \
+                            --replace-fail "none required" ""
+                        '';
+                      });
+                    }
+                  )
+                ];
               };
               # Default toolchain for devshell
               rustToolchain = pkgs.rust-bin.stable.latest.default.override {
@@ -80,7 +98,7 @@
                 libadwaita
                 librsvg
               ]
-              ++ lib.optionals pkgs.stdenv.isLinux [
+              ++ lib.optionals pkgs.stdenv.hostPlatform.isLinux [
                 libX11
                 libXtst
               ];

input-capture/src/libei.rs

@@ -18,12 +18,12 @@ use reis::{
 use std::{
     cell::Cell,
     collections::HashMap,
-    io,
+    env, io,
     num::NonZeroU32,
     os::unix::net::UnixStream,
     pin::Pin,
     rc::Rc,
-    sync::Arc,
+    sync::{Arc, LazyLock},
     task::{Context, Poll},
 };
 use tokio::{
@@ -50,6 +50,25 @@ use super::{
  * prevents receiving further events after a session has been disabled once.
  * Therefore the session needs to be recreated when the barriers are updated */
 
+/* mutter also kills the session whenever ei devices come and go, so there the
+ * whole session has to be torn down and recreated on every device change.
+ * Elsewhere that is pure overhead: each restart costs a CreateSession +
+ * ConnectToEIS round trip, and compositors that keep per-session state around
+ * (hyprland leaks a keymap fd per eis session, see hyprwm/Hyprland) can be
+ * driven out of file descriptors by the churn.
+ * Set LM_RESTART_SESSION_ON_DEVICE_CHANGE=1/0 to override the default. */
+static RESTART_SESSION_ON_DEVICE_CHANGE: LazyLock<bool> =
+    LazyLock::new(restart_session_on_device_change);
+
+fn restart_session_on_device_change() -> bool {
+    match env::var("LM_RESTART_SESSION_ON_DEVICE_CHANGE").as_deref() {
+        Ok("1") => true,
+        Ok("0") => false,
+        _ => env::var("XDG_CURRENT_DESKTOP")
+            .is_ok_and(|desktops| desktops.to_uppercase().split(':').any(|d| d == "GNOME")),
+    }
+}
+
 /// events that necessitate restarting the capture session
 #[derive(Clone, Copy, Debug)]
 enum LibeiNotifyEvent {
@@ -555,20 +574,32 @@ async fn handle_ei_event(
             s.seat.bind_capabilities(all_capabilities);
             context.flush().map_err(|e| io::Error::new(e.kind(), e))?;
         }
-        EiEvent::SeatRemoved(_) | /* EiEvent::DeviceAdded(_) | */ EiEvent::DeviceRemoved(_) => {
+        EiEvent::SeatRemoved(_) => {
             log::debug!("releasing session: {ei_event:?}");
             release_session.notify_waiters();
         }
+        /* EiEvent::DeviceAdded(_) | */
+        EiEvent::DeviceRemoved(_) => {
+            if *RESTART_SESSION_ON_DEVICE_CHANGE {
+                log::debug!("releasing session: {ei_event:?}");
+                release_session.notify_waiters();
+            } else {
+                log::debug!("ignoring device change: {ei_event:?}");
+            }
+        }
         EiEvent::DevicePaused(_) | EiEvent::DeviceResumed(_) => {}
         EiEvent::DeviceStartEmulating(_) => log::debug!("START EMULATING"),
         EiEvent::DeviceStopEmulating(_) => log::debug!("STOP EMULATING"),
         EiEvent::Disconnected(d) => {
-            return Err(CaptureError::Disconnected(format!("{:?}", d.reason)))
+            return Err(CaptureError::Disconnected(format!("{:?}", d.reason)));
         }
         _ => {
             if let Some(pos) = current_client {
                 for event in Event::from_ei_event(ei_event) {
-                    event_tx.send((pos, CaptureEvent::Input(event))).await.expect("no channel");
+                    event_tx
+                        .send((pos, CaptureEvent::Input(event)))
+                        .await
+                        .expect("no channel");
                 }
             }
         }

nix/default.nix

@@ -31,7 +31,7 @@ rustPlatform.buildRustPackage {
     libadwaita
     librsvg
   ]
-  ++ lib.optionals stdenv.isLinux [
+  ++ lib.optionals stdenv.hostPlatform.isLinux [
     libX11
     libXtst
   ];

nix/hm-module.nix

@@ -23,12 +23,12 @@ in {
     };
     systemd = mkOption {
       type = types.bool;
-      default = pkgs.stdenv.isLinux;
+      default = pkgs.stdenv.hostPlatform.isLinux;
       description = "Whether to enable to systemd service for lan-mouse on linux.";
     };
     launchd = mkOption {
       type = types.bool;
-      default = pkgs.stdenv.isDarwin;
+      default = pkgs.stdenv.hostPlatform.isDarwin;
       description = "Whether to enable to launchd service for lan-mouse on macOS.";
     };
     settings = lib.mkOption {