FIX: Make favorite work with multiple grant badges (#13492)

Badges that are awarded multiple times can be favorite and not favorite
at the same time. This caused few problems when users tried to favorite
them as they were counted multiple times or their state was incorrectly
displayed.

app/controllers/user_badges_controller.rb

@@ -105,11 +105,13 @@ class UserBadgesController < ApplicationController
       return render json: failed_json, status: 403
     end
 
-    if !user_badge.is_favorite && user_badges.where(is_favorite: true).count >= SiteSetting.max_favorite_badges
+    if !user_badge.is_favorite && user_badges.select(:badge_id).distinct.where(is_favorite: true).count >= SiteSetting.max_favorite_badges
       return render json: failed_json, status: 400
     end
 
-    user_badge.toggle!(:is_favorite)
+    UserBadge
+      .where(user_id: user_badge.user_id, badge_id: user_badge.badge_id)
+      .update(is_favorite: !user_badge.is_favorite)
     UserBadge.update_featured_ranks!(user_badge.user_id)
     render_serialized(user_badge, DetailedUserBadgeSerializer, root: :user_badge)
   end

spec/requests/user_badges_controller_spec.rb

@@ -309,5 +309,31 @@ describe UserBadgesController do
       user_badge = UserBadge.find_by(user: user, badge: badge)
       expect(user_badge.is_favorite).to be false
     end
+
+    it "works with multiple grants" do
+      SiteSetting.max_favorite_badges = 2
+
+      sign_in(user)
+
+      badge = Fabricate(:badge, multiple_grant: true)
+      user_badge = UserBadge.create(badge: badge, user: user, granted_by: Discourse.system_user, granted_at: Time.now, seq: 0, is_favorite: true)
+      user_badge2 = UserBadge.create(badge: badge, user: user, granted_by: Discourse.system_user, granted_at: Time.now, seq: 1, is_favorite: true)
+      other_badge = Fabricate(:badge)
+      other_user_badge = UserBadge.create(badge: other_badge, user: user, granted_by: Discourse.system_user, granted_at: Time.now)
+
+      put "/user_badges/#{user_badge.id}/toggle_favorite.json"
+      expect(response.status).to eq(200)
+      expect(user_badge.reload.is_favorite).to eq(false)
+      expect(user_badge2.reload.is_favorite).to eq(false)
+
+      put "/user_badges/#{user_badge.id}/toggle_favorite.json"
+      expect(response.status).to eq(200)
+      expect(user_badge.reload.is_favorite).to eq(true)
+      expect(user_badge2.reload.is_favorite).to eq(true)
+
+      put "/user_badges/#{other_user_badge.id}/toggle_favorite.json"
+      expect(response.status).to eq(200)
+      expect(other_user_badge.reload.is_favorite).to eq(true)
+    end
   end
 end