Fix issue with merging existing settings when updating campaign via API

lib/keila_web/api/controllers/api_campaign_controller.ex

@@ -79,8 +79,13 @@ defmodule KeilaWeb.ApiCampaignController do
     project_id = project_id(conn)
 
     with campaign = %Mailings.Campaign{} <- Mailings.get_project_campaign(project_id, id) do
-      settings_id = campaign.settings.id
-      params = put_in(conn.body_params.data, [:settings, :id], settings_id)
+      settings_params =
+        campaign.settings
+        |> Mailings.Campaign.Settings.changeset(conn.body_params.data[:settings] || %{})
+        |> Ecto.Changeset.apply_changes()
+        |> Map.from_struct()
+
+      params = Map.put(conn.body_params.data, :settings, settings_params)
 
       case Mailings.update_campaign(id, params) do
         {:ok, campaign} -> render(conn, "campaign.json", %{campaign: campaign})

test/keila_web/api/api_campaign_controller_test.exs

@@ -84,6 +84,26 @@ defmodule KeilaWeb.ApiCampaignControllerTest do
 
       assert %{subject: "Updated Subject"} = Keila.Mailings.get_campaign(id)
     end
+
+    @tag :api_campaign_controller
+    test "also works when settings are not provided", %{authorized_conn: conn, project: project} do
+      %{id: id} = insert!(:mailings_campaign, project_id: project.id, settings: %{type: "mjml"})
+
+      body = %{"data" => %{"subject" => "Updated Subject"}}
+      conn = patch_json(conn, Routes.api_campaign_path(conn, :update, id), body)
+
+      assert %{
+               "data" => %{
+                 "id" => ^id,
+                 "subject" => "Updated Subject",
+                 "settings" => %{
+                   "type" => "mjml"
+                 }
+               }
+             } = json_response(conn, 200)
+
+      assert %{subject: "Updated Subject"} = Keila.Mailings.get_campaign(id)
+    end
   end
 
   describe "DELETE /api/v1/campaigns/:id" do