fix(auth): redirect a live-view socket in the user-required guard

LiveSession.assign_new_resources/2 is typed to return a Phoenix.Socket, which made the on_mount redirect type-incompatible. The authenticated-routes live_session already assigns current_user, so the guard reads it from socket.assigns directly. Also assign the locale into the socket actually used by the no-user redirect instead of discarding it.

lib/mv_web/live_user_auth.ex

@@ -31,27 +31,24 @@ defmodule MvWeb.LiveUserAuth do
     end
   end
 
-  def on_mount(:live_user_required, _params, session, socket) do
+  def on_mount(:live_user_required, _params, _session, socket) do
-    socket = LiveSession.assign_new_resources(socket, session)
-
     case socket.assigns do
       %{current_user: %{} = user} ->
         {:cont, assign(socket, :current_user, user)}
 
       _ ->
-        socket = LiveView.redirect(socket, to: ~p"/sign-in")
+        {:halt, LiveView.redirect(socket, to: ~p"/sign-in")}
-        {:halt, socket}
     end
   end
 
   def on_mount(:live_no_user, _params, session, socket) do
     # Set the locale for not logged in user (default from config, "de" in dev/prod).
     locale = session["locale"] || Application.get_env(:mv, :default_locale, "de")
-    Gettext.put_locale(MvWeb.Gettext, locale)
+    _ = Gettext.put_locale(MvWeb.Gettext, locale)
-    {:cont, assign(socket, :locale, locale)}
+    socket = assign(socket, :locale, locale)
 
     if socket.assigns[:current_user] do
-      {:halt, Phoenix.LiveView.redirect(socket, to: ~p"/")}
+      {:halt, LiveView.redirect(socket, to: ~p"/")}
     else
       {:cont, assign(socket, :current_user, nil)}
     end

test/mv_web/live_user_auth_test.exs

@@ -0,0 +1,35 @@
+defmodule MvWeb.LiveUserAuthTest do
+  @moduledoc """
+  Regression tests for the `MvWeb.LiveUserAuth` on_mount guards:
+  the unauthenticated `:live_user_required` redirect to the sign-in page and
+  the authenticated `:live_no_user` redirect away from the sign-in page.
+  """
+  use MvWeb.ConnCase, async: false
+
+  import Phoenix.LiveViewTest
+
+  describe ":live_user_required" do
+    @tag role: :unauthenticated
+    test "unauthenticated request to a protected route is redirected to sign-in", %{conn: conn} do
+      assert {:error, {:redirect, %{to: to}}} = live(conn, "/members")
+      assert to == "/sign-in"
+    end
+
+    @tag role: :admin
+    test "authenticated user can mount a protected route", %{conn: conn} do
+      assert {:ok, _view, _html} = live(conn, "/members")
+    end
+  end
+
+  describe ":live_no_user" do
+    @tag role: :admin
+    test "authenticated user visiting the sign-in page is redirected to root", %{conn: conn} do
+      assert {:error, {:redirect, %{to: "/"}}} = live(conn, "/sign-in")
+    end
+
+    @tag role: :unauthenticated
+    test "unauthenticated user can reach the sign-in page", %{conn: conn} do
+      assert {:ok, _view, _html} = live(conn, "/sign-in")
+    end
+  end
+end