fix: handle alert_changed message in DashboardLive (#189)

Fixes FunctionClauseError when DashboardLive receives {:alert_changed, org_id}
message broadcast by user_auth hooks.

The user_auth module subscribes all LiveViews to the
"organization:#{org_id}:alerts" topic and broadcasts {:alert_changed, org_id}
messages when alerts are created or resolved. DashboardLive was missing a
handle_info/2 clause to handle this message format, causing crashes in
production.

Solution:
- Added handle_info/2 clause for {:alert_changed, _org_id} message
- Uses existing debounced reload pattern to update dashboard
- Added test to verify message is handled without crashing
- Updated both technical and user-facing changelogs

All tests pass. The fix follows the same pattern used in AlertLive.Index
and DeviceLive.Show.

Reviewed-on: graham/towerops-web#189

CHANGELOG.txt

@@ -1,3 +1,12 @@
+2026-03-27
+fix: handle alert_changed message in DashboardLive
+  - Fixed FunctionClauseError when DashboardLive receives {:alert_changed, org_id} message
+  - Added handle_info/2 clause to handle alert_changed broadcasts from user_auth hooks
+  - Uses existing debounced reload pattern to update dashboard when alerts change
+  - Added test to verify the message is handled without crashing
+  - All LiveViews now properly subscribed to organization:#{org_id}:alerts topic
+  Files: lib/towerops_web/live/dashboard_live.ex, test/towerops_web/live/dashboard_live_test.exs
+
 2026-03-27
 docs: comprehensive audit review and verification
   - Verified all 47 Process.sleep instances in tests are intentional, not flaky

lib/towerops_web/live/dashboard_live.ex

@@ -86,6 +86,11 @@ defmodule ToweropsWeb.DashboardLive do
     {:noreply, schedule_debounced_dashboard_reload(socket)}
   end
 
+  @impl true
+  def handle_info({:alert_changed, _org_id}, socket) do
+    {:noreply, schedule_debounced_dashboard_reload(socket)}
+  end
+
   @impl true
   def handle_info(:debounced_dashboard_reload, socket) do
     {:noreply, load_dashboard_data(socket, socket.assigns.current_scope.organization.id)}

priv/static/changelog.txt

@@ -1,3 +1,7 @@
+2026-03-27 — Stability Improvements
+* Fixed dashboard crashes when alerts change
+* Improved real-time alert updates reliability
+
 2026-03-27 — Code Quality and Performance Improvements
 * Improved code architecture by better organizing database queries
 * Added database indexes to speed up array-based queries

test/towerops_web/live/dashboard_live_test.exs

@@ -357,6 +357,25 @@ defmodule ToweropsWeb.DashboardLiveTest do
       html = render(view)
       refute html =~ "Device went down"
     end
+
+    test "handles alert_changed broadcasts without crashing", %{
+      conn: conn,
+      organization: organization
+    } do
+      {:ok, view, _html} = live(conn, ~p"/dashboard")
+
+      # Broadcast alert_changed message (sent by user_auth hooks)
+      Phoenix.PubSub.broadcast(
+        Towerops.PubSub,
+        "organization:#{organization.id}:alerts",
+        {:alert_changed, organization.id}
+      )
+
+      # Should not crash and should remain connected
+      # Verify we can still render the page
+      html = render(view)
+      assert html =~ organization.name
+    end
   end
 
   defp create_device(organization, site, name \\ "Test Device", ip \\ "192.168.1.1") do