Keep group identity in live match payload

app/serializers/live_match_serializer.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 class LiveMatchSerializer < ApplicationSerializer
-  attributes :position, :state, :teams
+  attributes :position, :state, :teams, :group, :stage
 
   has_many :match_scores
 
@@ -13,4 +13,24 @@ class LiveMatchSerializer < ApplicationSerializer
       }
     end
   end
+
+  def group
+    return nil if object.group.nil?
+
+    {
+      id: object.group.id,
+      number: object.group.number
+    }
+  end
+
+  def stage
+    stage = object.stage || object.group&.stage
+    return nil if stage.nil?
+
+    {
+      id: stage.id,
+      level: stage.level,
+      state: stage.state
+    }
+  end
 end

doc/tournament_live_updates.md

@@ -91,6 +91,8 @@ Use this when page only needs match cards/list updates:
 - match id
 - position
 - state
+- group identity
+- stage identity
 - teams
 - score rows
 
@@ -136,6 +138,15 @@ Payload:
       "id": 456,
       "position": 0,
       "state": "in_progress",
+      "group": {
+        "id": 44,
+        "number": 1
+      },
+      "stage": {
+        "id": 33,
+        "level": -1,
+        "state": "in_progress"
+      },
       "teams": [
         {
           "id": 10,
@@ -234,7 +245,7 @@ Recommended update handling:
 
 - do not patch a single nested field from websocket payload
 - replace the full snapshot for that channel/filter
-- use `match.id`, `team.id`, and `match_score.id` as stable keys
+- use `match.id`, `group.id`, `stage.id`, `team.id`, and `match_score.id` as stable keys
 - tolerate duplicate payloads
 - tolerate fast sequences like score update followed by match finish
 

spec/controllers/matches_controller_spec.rb

@@ -47,7 +47,7 @@ RSpec.describe MatchesController, type: :controller do
         get :index, params: { tournament_id: @tournament.to_param }
         match = deserialize_response(response).first
 
-        expect(match.keys).to match_array(%i[id position state teams match_scores])
+        expect(match.keys).to match_array(%i[id position state teams match_scores group stage])
         expect(match[:teams]).to all(include(:id, :name))
       end
     end

spec/services/tournament_live_payload_spec.rb

@@ -21,14 +21,16 @@ RSpec.describe 'Tournament live payloads' do
   describe TournamentMatchesPayload do
     it 'serializes only match live fields used by matches API and websocket' do
       tournament = create(:group_stage_tournament, match_factory: :filled_group_match)
-      match = tournament.matches.first
+      match = tournament.stages.find { |stage| stage.level == -1 }.groups.first.matches.first
 
       payload = described_class.build(tournament)
       serialized_match = payload.find { |candidate| candidate[:id] == match.id }
 
-      expect(serialized_match.keys).to match_array(%i[id position state teams match_scores])
+      expect(serialized_match.keys).to match_array(%i[id position state teams match_scores group stage])
       expect(serialized_match[:state]).to eq(match.state)
       expect(serialized_match[:position]).to eq(match.position)
+      expect(serialized_match.dig(:group, :id)).to eq(match.group_id)
+      expect(serialized_match.dig(:stage, :id)).to eq(match.group.stage_id)
       expect(serialized_match[:teams].map { |team| team[:id] }).to match_array(match.teams.map(&:id))
       expect(serialized_match[:match_scores].map { |score| score[:team][:id] }).to match_array(match.teams.map(&:id))
     end