Fix broken `project_url` routing when protected branches are accessed with an empty repo

app/helpers/gitlab_routing_helper.rb

@@ -28,4 +28,20 @@ module GitlabRoutingHelper
   def merge_request_path(entity, *args)
     namespace_project_merge_request_path(entity.project.namespace, entity.project, entity, *args)
   end
+
+  def project_url(project, *args)
+    namespace_project_url(project.namespace, project, *args)
+  end
+
+  def edit_project_url(project, *args)
+    edit_namespace_project_url(project.namespace, project, *args)
+  end
+
+  def issue_url(entity, *args)
+    namespace_project_issue_url(entity.project.namespace, entity.project, entity, *args)
+  end
+
+  def merge_request_url(entity, *args)
+    namespace_project_merge_request_url(entity.project.namespace, entity.project, entity, *args)
+  end
 end

spec/controllers/projects/protected_branches_controller_spec.rb

+require('spec_helper')
+
+describe Projects::ProtectedBranchesController do
+  describe "GET #index" do
+    let(:project) { create(:project_empty_repo, :public) }
+    it "redirect empty repo to projects page" do
+      get(:index, namespace_id: project.namespace.to_param, project_id: project.to_param)
+    end
+  end
+end