Fix board serialization when milestone is set to upcoming

app/controllers/projects/boards_controller.rb

@@ -84,9 +84,9 @@ class Projects::BoardsController < Projects::ApplicationController
 
   def serialize_as_json(resource)
     resource.as_json(
-      only: [:id, :name, :milestone_id],
+      only: [:id, :name],
       include: {
-        milestone: { only: [:title] }
+        milestone: { only: [:id, :title] }
       }
     )
   end

app/models/board.rb

@@ -17,4 +17,18 @@ class Board < ActiveRecord::Base
       super
     end
   end
+
+  def as_json(options = {})
+    milestone_attrs = options.fetch(:include, {})
+                             .extract!(:milestone)
+                             .dig(:milestone, :only)
+
+    super(options).tap do |json|
+      if milestone.present? && milestone_attrs.present?
+        json[:milestone] = milestone_attrs.each_with_object({}) do |attr, json|
+          json[attr] = milestone.public_send(attr)
+        end
+      end
+    end
+  end
 end

spec/controllers/projects/boards_controller_spec.rb

@@ -39,7 +39,8 @@ describe Projects::BoardsController do
 
     context 'when format is JSON' do
       it 'returns a list of project boards' do
-        create_list(:board, 2, project: project)
+        create(:board, project: project, milestone: create(:milestone, project: project))
+        create(:board, project: project, milestone_id: Milestone::Upcoming.id)
 
         list_boards format: :json
 

spec/fixtures/api/schemas/board.json

@@ -6,7 +6,11 @@
   ],
   "properties" : {
     "id": { "type": "integer" },
-    "name": { "type": "string" }
+    "name": { "type": "string" },
+    "milestone": {
+      "id": { "type": "integer" },
+      "title": { "type": "string" }
+    }
   },
   "additionalProperties": false
 }