Fixed dashboard milestone tabs not loading

Closes #33477

app/controllers/concerns/milestone_actions.rb

@@ -46,8 +46,10 @@ module MilestoneActions
   def milestone_redirect_path
     if @project
       namespace_project_milestone_path(@project.namespace, @project, @milestone)
-    else
+    elsif @group
       group_milestone_path(@group, @milestone.safe_title, title: @milestone.title)
+    else
+      dashboard_milestone_path(@milestone.safe_title, title: @milestone.title)
     end
   end
 end

app/controllers/dashboard/milestones_controller.rb

 class Dashboard::MilestonesController < Dashboard::ApplicationController
+  include MilestoneActions
+
   before_action :projects
-  before_action :milestone, only: [:show]
+  before_action :milestone, only: [:show, :merge_requests, :participants, :labels]
 
   def index
     respond_to do |format|

app/helpers/milestones_helper.rb

@@ -121,6 +121,8 @@ module MilestonesHelper
       merge_requests_namespace_project_milestone_path(@project.namespace, @project, milestone, format: :json)
     elsif @group
       merge_requests_group_milestone_path(@group, milestone.safe_title, title: milestone.title, format: :json)
+    else
+      merge_requests_dashboard_milestone_path(milestone, title: milestone.title, format: :json)
     end
   end
 
@@ -129,6 +131,8 @@ module MilestonesHelper
       participants_namespace_project_milestone_path(@project.namespace, @project, milestone, format: :json)
     elsif @group
       participants_group_milestone_path(@group, milestone.safe_title, title: milestone.title, format: :json)
+    else
+      participants_dashboard_milestone_path(milestone, title: milestone.title, format: :json)
     end
   end
 
@@ -137,6 +141,8 @@ module MilestonesHelper
       labels_namespace_project_milestone_path(@project.namespace, @project, milestone, format: :json)
     elsif @group
       labels_group_milestone_path(@group, milestone.safe_title, title: milestone.title, format: :json)
+    else
+      labels_dashboard_milestone_path(milestone, title: milestone.title, format: :json)
     end
   end
 end

changelogs/unreleased/dashboard-milestone-tabs-loading-async.yml

+---
+title: Fixed dashboard milestone tabs not loading
+merge_request:
+author:

config/routes/dashboard.rb

@@ -4,7 +4,13 @@ resource :dashboard, controller: 'dashboard', only: [] do
   get :activity
 
   scope module: :dashboard do
-    resources :milestones, only: [:index, :show]
+    resources :milestones, only: [:index, :show] do
+      member do
+        get :merge_requests
+        get :participants
+        get :labels
+      end
+    end
     resources :labels, only: [:index]
 
     resources :groups, only: [:index]

spec/controllers/dashboard/milestones_controller_spec.rb

+require 'spec_helper'
+
+describe Dashboard::MilestonesController do
+  let(:project) { create(:empty_project) }
+  let(:user)    { create(:user) }
+  let(:project_milestone) { create(:milestone, project: project) }
+  let(:milestone) do
+    DashboardMilestone.build(
+      [project],
+      project_milestone.title
+    )
+  end
+  let(:issue) { create(:issue, project: project, milestone: project_milestone) }
+  let!(:label) { create(:label, project: project, title: 'Issue Label', issues: [issue]) }
+  let!(:merge_request) { create(:merge_request, source_project: project, target_project: project, milestone: project_milestone) }
+  let(:milestone_path) { dashboard_milestone_path(milestone.safe_title, title: milestone.title) }
+
+  before do
+    sign_in(user)
+    project.team << [user, :master]
+  end
+
+  it_behaves_like 'milestone tabs'
+
+  describe "#show" do
+    render_views
+
+    def view_milestone
+      get :show, id: milestone.safe_title, title: milestone.title
+    end
+
+    it 'shows milestone page' do
+      view_milestone
+
+      expect(response).to have_http_status(200)
+    end
+  end
+end

spec/features/dashboard/milestone_tabs_spec.rb

+require 'spec_helper'
+
+describe 'Dashboard milestone tabs', :js, :feature do
+  let(:user) { create(:user) }
+  let(:project) { create(:empty_project) }
+  let!(:label) { create(:label, project: project) }
+  let(:project_milestone) { create(:milestone, project: project) }
+  let(:milestone) do
+    DashboardMilestone.build(
+      [project],
+      project_milestone.title
+    )
+  end
+  let!(:merge_request) { create(:labeled_merge_request, source_project: project, target_project: project, milestone: project_milestone, labels: [label]) }
+
+  before do
+    project.add_master(user)
+    login_as(user)
+
+    visit dashboard_milestone_path(milestone.safe_title, title: milestone.title)
+  end
+
+  it 'loads merge requests async' do
+    click_link 'Merge Requests'
+
+    expect(page).to have_selector('.merge_requests-sortable-list')
+  end
+
+  it 'loads participants async' do
+    click_link 'Participants'
+
+    expect(page).to have_selector('#tab-participants .bordered-list')
+  end
+
+  it 'loads labels async' do
+    click_link 'Labels'
+
+    expect(page).to have_selector('#tab-labels .bordered-list')
+  end
+end

spec/support/milestone_tabs_examples.rb

 shared_examples 'milestone tabs' do
   def go(path, extra_params = {})
-    params = if milestone.is_a?(GlobalMilestone)
+    params =
+      case milestone
+      when DashboardMilestone
+        { id: milestone.safe_title, title: milestone.title }
+      when GroupMilestone
         { group_id: group.to_param, id: milestone.safe_title, title: milestone.title }
       else
         { namespace_id: project.namespace.to_param, project_id: project, id: milestone.iid }