Filter group milestones based on user membership

app/controllers/dashboard/milestones_controller.rb

@@ -22,7 +22,7 @@ class Dashboard::MilestonesController < Dashboard::ApplicationController
   private
 
   def group_milestones
-    groups = GroupsFinder.new(current_user, all_available: true).execute
+    groups = GroupsFinder.new(current_user, all_available: false).execute
 
     DashboardGroupMilestone.build_collection(groups)
   end

app/models/dashboard_group_milestone.rb

@@ -13,7 +13,7 @@ class DashboardGroupMilestone < GlobalMilestone
   end
 
   def self.build_collection(groups)
-    MilestonesFinder.new(group_ids: groups.pluck(:id)).execute.map { |m| new(m) } # rubocop: disable CodeReuse/Finder
+    MilestonesFinder.new(group_ids: groups.select(:id)).execute.map { |m| new(m) } # rubocop: disable CodeReuse/Finder
   end
 
   override :group_milestone?

changelogs/unreleased/ccr-50483_add_filter_for_group_milestones.yml

@@ -0,0 +1,5 @@
+---
+title: Filter group milestones based on user membership.
+merge_request: 21660
+author:
+type: fixed

spec/controllers/dashboard/milestones_controller_spec.rb

@@ -3,9 +3,11 @@ require 'spec_helper'
 describe Dashboard::MilestonesController do
   let(:project) { create(:project) }
   let(:group) { create(:group) }
+  let(:public_group) { create(:group, :public) }
   let(:user) { create(:user) }
   let(:project_milestone) { create(:milestone, project: project) }
   let(:group_milestone) { create(:milestone, group: group) }
+  let!(:public_milestone) { create(:milestone, group: public_group) }
   let(:milestone) do
     DashboardMilestone.build(
       [project],
@@ -43,13 +45,13 @@ describe Dashboard::MilestonesController do
   end
 
   describe "#index" do
-    it 'should contain group and project milestones' do
+    it 'returns group and project milestones to which the user belongs' do
       get :index, format: :json
 
       expect(response).to have_gitlab_http_status(200)
       expect(json_response.size).to eq(2)
-      expect(json_response.map { |i| i["first_milestone"]["id"] }).to include(group_milestone.id, project_milestone.id)
-      expect(json_response.map { |i| i["group_name"] }).to include(group.name)
+      expect(json_response.map { |i| i["first_milestone"]["id"] }).to match_array([group_milestone.id, project_milestone.id])
+      expect(json_response.map { |i| i["group_name"] }.compact).to match_array(group.name)
     end
   end
 end

spec/features/dashboard/milestones_spec.rb

@@ -17,8 +17,9 @@ describe 'Dashboard > Milestones' do
     let(:project) { create(:project, namespace: user.namespace) }
     let!(:milestone) { create(:milestone, project: project) }
     let!(:milestone2) { create(:milestone, group: group) }
+
     before do
-      project.add_maintainer(user)
+      group.add_developer(user)
       sign_in(user)
       visit dashboard_milestones_path
     end