3 files changed, 48 insertions, 2 deletions
diff --git a/app/controllers/concerns/milestone_actions.rb b/app/controllers/concerns/milestone_actions.rb
new file mode 100644
index 00000000000..c28d08201e0
--- /dev/null
+++ b/app/controllers/concerns/milestone_actions.rb
@@ -0,0 +1,42 @@
+module MilestoneActions
+  extend ActiveSupport::Concern
+
+  def merge_requests
+    respond_to do |format|
+      format.json do
+        render json: tabs_json("shared/milestones/_merge_requests_tab", {
+          merge_requests: @milestone.merge_requests,
+          show_project_name: true
+        })
+      end
+    end
+  end
+
+  def participants
+    respond_to do |format|
+      format.json do
+        render json: tabs_json("shared/milestones/_participants_tab", {
+          users: @milestone.participants
+        })
+      end
+    end
+  end
+
+  def labels
+    respond_to do |format|
+      format.json do
+        render json: tabs_json("shared/milestones/_labels_tab", {
+          labels: @milestone.labels
+        })
+      end
+    end
+  end
+
+  private
+
+  def tabs_json(partial, data = {})
+    {
+      html: view_to_html_string(partial, data)
+    }
+  end
+end
diff --git a/app/controllers/groups/milestones_controller.rb b/app/controllers/groups/milestones_controller.rb
index 43102596201..e52fa766044 100644
--- a/app/controllers/groups/milestones_controller.rb
+++ b/app/controllers/groups/milestones_controller.rb
@@ -1,6 +1,8 @@
 class Groups::MilestonesController < Groups::ApplicationController
+  include MilestoneActions
+
   before_action :group_projects
-  before_action :milestone, only: [:show, :update]
+  before_action :milestone, only: [:show, :update, :merge_requests, :participants, :labels]
   before_action :authorize_admin_milestones!, only: [:new, :create, :update]
 
   def index
diff --git a/app/controllers/projects/milestones_controller.rb b/app/controllers/projects/milestones_controller.rb
index d0dd524c484..5c270501a24 100644
--- a/app/controllers/projects/milestones_controller.rb
+++ b/app/controllers/projects/milestones_controller.rb
@@ -1,6 +1,8 @@
 class Projects::MilestonesController < Projects::ApplicationController
+  include MilestoneActions
+
   before_action :module_enabled
-  before_action :milestone, only: [:edit, :update, :destroy, :show, :sort_issues, :sort_merge_requests]
+  before_action :milestone, only: [:edit, :update, :destroy, :show, :sort_issues, :sort_merge_requests, :merge_requests, :participants, :labels]
 
   # Allow read any milestone
   before_action :authorize_read_milestone!