fix(macos): associate wx notifications with main frame

- Call wxNotificationMessage:setParent/2 on macOS so Notification Center ties
  the toast to the app window (wx default main window can be wrong for BEAM).
- Log when show/2 returns false with pointers to issue #38 and settings.
- Add ELIXIR_DESKTOP_OS=macos for testable macOS branches; add OS.macos?/0.
- Guard notification_new/show when NO_WX yields nil notification refs.

Refs #38

Co-authored-by: Dominic Letz <dominicletz@users.noreply.github.com>

Author: cursoragent

lib/desktop/fallback.ex

@@ -2,6 +2,13 @@ defmodule Desktop.Fallback do
   require Logger
   alias Desktop.{Wx, OS}
 
+  @notification_show_failed """
+  wxWidgets failed to show a desktop notification (wxNotificationMessage:show/2 returned false). \
+  On macOS, ensure notifications are enabled for the app in System Settings, use a packaged .app \
+  with matching bundle id / Info.plist for the Erlang VM, and see \
+  https://github.com/elixir-desktop/desktop/issues/38 \
+  """
+
   @moduledoc """
     Fallback handles version differences in the :wx modules needed for showing the
     WebView and Desktop notifications and it uses the highest available
@@ -170,7 +177,7 @@ defmodule Desktop.Fallback do
     webview
   end
 
-  def notification_new(title, type) do
+  def notification_new(title, type, parent \\ nil) do
     if module?(:wxNotificationMessage) do
       flag =
         case type do
@@ -180,8 +187,9 @@ defmodule Desktop.Fallback do
         end
 
       notification = call(:wxNotificationMessage, :new, [title, [flags: flag]])
+      notification_set_parent(notification, parent)
 
-      if notification_events_available?() do
+      if notification != nil and notification_events_available?() do
         for event <- [
               :notification_message_click,
               :notification_message_dismissed,
@@ -190,9 +198,11 @@ defmodule Desktop.Fallback do
           call(:wxNotificationMessage, :connect, [notification, event])
         end
       else
-        Logger.warning(
-          "Missing support for wxNotificationMessage Events - upgrade to wxWidgets 3.1 - messages won't be clickable"
-        )
+        if notification != nil do
+          Logger.warning(
+            "Missing support for wxNotificationMessage Events - upgrade to wxWidgets 3.1 - messages won't be clickable"
+          )
+        end
       end
 
       notification
@@ -204,13 +214,20 @@ defmodule Desktop.Fallback do
   end
 
   def notification_show(notification, message, timeout, title \\ nil) do
-    if module?(:wxNotificationMessage) do
+    if module?(:wxNotificationMessage) and notification != nil do
       if title != nil do
         call(:wxNotificationMessage, :setTitle, [notification, to_charlist(title)])
       end
 
       call(:wxNotificationMessage, :setMessage, [notification, to_charlist(message)])
-      call(:wxNotificationMessage, :show, [notification, [timeout: timeout]])
+
+      case call(:wxNotificationMessage, :show, [notification, [timeout: timeout]]) do
+        false ->
+          Logger.warning(@notification_show_failed)
+
+        _ ->
+          :ok
+      end
     else
       Logger.notice("NOTIFICATION: #{title}: #{message}")
     end
@@ -244,6 +261,14 @@ defmodule Desktop.Fallback do
     end
   end
 
+  defp notification_set_parent(notification, parent) do
+    if notification != nil and parent != nil and OS.macos?() and
+         module?(:wxNotificationMessage) and
+         Kernel.function_exported?(:wxNotificationMessage, :setParent, 2) do
+      call(:wxNotificationMessage, :setParent, [notification, parent])
+    end
+  end
+
   defp call(module, method, args \\ []) do
     if System.get_env("NO_WX") == nil and Code.ensure_loaded?(module) and
          Kernel.function_exported?(module, method, length(args)) do

lib/desktop/os.ex

@@ -11,6 +11,10 @@ defmodule Desktop.OS do
     - Windows
     - Linux
 
+    `ELIXIR_DESKTOP_OS` can be set to `android`, `ios`, or `macos` to force the
+    corresponding type (useful in tests). On real devices, omit it and the OS is
+    detected from `:os.type()`.
+
   """
 
   @doc """
@@ -45,6 +49,11 @@ defmodule Desktop.OS do
       "ios" ->
         IOS
 
+      # Lets CI and Linux developers run macOS-specific branches (e.g. notification wiring)
+      # without a Darwin host. Not used in production builds.
+      "macos" ->
+        MacOS
+
       _ ->
         case :os.type() do
           {:unix, :darwin} -> MacOS
@@ -93,6 +102,9 @@ defmodule Desktop.OS do
     end
   end
 
+  @doc false
+  def macos?(), do: type() == MacOS
+
   defp kill_heart() do
     heart = Process.whereis(:heart)
 

lib/desktop/window.ex

@@ -196,7 +196,7 @@ defmodule Desktop.Window do
         wx_menubar
       end
 
-    if OS.type() == MacOS do
+    if OS.macos?() do
       update_apple_menu(window_title, frame, wx_menubar || :wxMenuBar.new())
     end
 
@@ -468,6 +468,12 @@ defmodule Desktop.Window do
         * `:callback` - A function to be executed when the user clicks on the
           notification.
 
+    On macOS, notifications are associated with the main `wxFrame` via
+    `wxNotificationMessage:setParent/2` so they follow the same app identity as
+    the visible window. If nothing appears, check System Settings → Notifications
+    and (for distributed apps) bundle id / Info.plist alignment for the VM
+    (see GitHub issue #38).
+
   ## Examples
 
       iex> Desktop.Window.show_notification(pid, "Hello, world!")
@@ -658,7 +664,7 @@ defmodule Desktop.Window do
     {n, _} =
       note =
       case Map.get(noties, id, nil) do
-        nil -> {Fallback.notification_new(title || window_title, type), callback}
+        nil -> {Fallback.notification_new(title || window_title, type, frame), callback}
         {note, _} -> {note, callback}
       end
 

test/fallback_notification_test.exs

@@ -0,0 +1,25 @@
+defmodule Desktop.FallbackNotificationTest do
+  use ExUnit.Case
+
+  describe "notification_new/3" do
+    test "parent option does not crash when wx is disabled (NO_WX)" do
+      old_no_wx = System.get_env("NO_WX")
+      old_os = System.get_env("ELIXIR_DESKTOP_OS")
+
+      on_exit(fn ->
+        restore_env("NO_WX", old_no_wx)
+        restore_env("ELIXIR_DESKTOP_OS", old_os)
+      end)
+
+      System.put_env("NO_WX", "1")
+      System.put_env("ELIXIR_DESKTOP_OS", "macos")
+
+      assert Desktop.OS.macos?()
+      # Parent is ignored when notification object cannot be created; must not raise.
+      assert Desktop.Fallback.notification_new("Title", :info, :not_a_wx_window) == nil
+    end
+  end
+
+  defp restore_env(key, nil), do: System.delete_env(key)
+  defp restore_env(key, value), do: System.put_env(key, value)
+end

test/os_test.exs

@@ -0,0 +1,20 @@
+defmodule Desktop.OSTest do
+  use ExUnit.Case
+
+  describe "type/0 and ELIXIR_DESKTOP_OS" do
+    test "macos override forces MacOS for tests and CI" do
+      old = System.get_env("ELIXIR_DESKTOP_OS")
+
+      try do
+        System.put_env("ELIXIR_DESKTOP_OS", "macos")
+        assert Desktop.OS.type() == MacOS
+      after
+        if old do
+          System.put_env("ELIXIR_DESKTOP_OS", old)
+        else
+          System.delete_env("ELIXIR_DESKTOP_OS")
+        end
+      end
+    end
+  end
+end