fix dashboard query by using .preload

app/queries/dashboard_query.rb

@@ -3,10 +3,7 @@ class DashboardQuery
   MAX_WORKSHOP_QUERY = 10
 
   def self.upcoming_events
-    workshops = Workshop.eager_load(:chapter, :sponsors, :organisers, :permissions, :workshop_host)
-                        .today_and_upcoming
-                        .limit(MAX_WORKSHOP_QUERY)
-                        .to_a
+    workshops = upcoming_workshops
     sorted_events = all_events(workshops).sort_by(&:date_and_time)
 
     limited_events = []
@@ -57,4 +54,13 @@ def self.all_events(workshops)
     [*workshops, *events, meeting].uniq.compact
   end
   private_class_method :all_events
+
+  def self.upcoming_workshops
+    Workshop.eager_load(:chapter, :sponsors, :organisers, :permissions)
+            .preload(workshop_host: :sponsor)
+            .today_and_upcoming
+            .limit(MAX_WORKSHOP_QUERY)
+            .to_a
+  end
+  private_class_method :upcoming_workshops
 end

spec/queries/dashboard_query_spec.rb

@@ -16,6 +16,25 @@
       expect(result.values.flatten).to include(workshop, event, meeting)
     end
 
+    it 'loads each workshop host when workshops have multiple sponsors and organisers' do
+      chapter = Fabricate(:chapter)
+      additional_sponsor = Fabricate(:sponsor)
+      host = Fabricate(:sponsor)
+      organisers = Fabricate.times(2, :member)
+      workshops = Fabricate.times(16, :workshop_no_sponsor, chapter:)
+
+      workshops.each do |workshop|
+        Fabricate(:workshop_sponsor, workshop:, sponsor: additional_sponsor)
+        Fabricate(:workshop_sponsor, workshop:, sponsor: host, host: true)
+        organisers.each { |organiser| organiser.add_role(:organiser, workshop) }
+      end
+
+      result = described_class.upcoming_events
+
+      expect(result.values.flatten.select { |event| event.is_a?(Workshop) }.map(&:host))
+        .to all(eq(host))
+    end
+
     it 'limits to exactly 3 distinct dates' do
       Fabricate(:workshop, date_and_time: 1.day.from_now)
       Fabricate(:workshop, date_and_time: 2.days.from_now)