Implement maintainer feedback

Add canonical links helper for specs
Reduce factory usage
Remove extra description blocks

app/helpers/page_layout_helper.rb

@@ -40,6 +40,14 @@ module PageLayoutHelper
     end
   end
 
+  def page_canonical_link(link = nil)
+    if link
+      @page_canonical_link = link
+    else
+      @page_canonical_link
+    end
+  end
+
   def favicon
     Gitlab::Favicon.main
   end

app/models/issue.rb

@@ -19,6 +19,7 @@ class Issue < ApplicationRecord
   include WhereComposite
   include StateEventable
   include IdInOrdered
+  include Presentable
 
   DueDateStruct                   = Struct.new(:title, :name).freeze
   NoDueDate                       = DueDateStruct.new('No Due Date', '0').freeze
@@ -417,6 +418,10 @@ class Issue < ApplicationRecord
     IssueLink.inverse_link_type(type)
   end
 
+  def relocation_target
+    moved_to || duplicated_to
+  end
+
   private
 
   def ensure_metrics

app/views/layouts/_head.html.haml

@@ -42,6 +42,9 @@
   %title= page_title(site_name)
   %meta{ name: "description", content: page_description }
 
+  - if page_canonical_link
+    %link{ rel: 'canonical', href: page_canonical_link }
+
   = favicon_link_tag favicon, id: 'favicon', data: { original_href: favicon }, type: 'image/png'
 
   = render 'layouts/startup_css'

app/views/projects/issues/show.html.haml

@@ -4,6 +4,8 @@
 - page_title           "#{@issue.title} (#{@issue.to_reference})", _("Issues")
 - page_description     @issue.description
 - page_card_attributes @issue.card_attributes
+- if @issue.relocation_target
+  - page_canonical_link @issue.relocation_target.present(current_user: current_user).web_url
 
 - can_update_issue = can?(current_user, :update_issue, @issue)
 - can_reopen_issue = can?(current_user, :reopen_issue, @issue)

changelogs/unreleased/jyavorska-master-patch-96769.yml

+---
+title: Add canonical links for moved/duplicated issues
+merge_request: 34604
+author:
+type: added

ee/app/helpers/ee/gitlab_routing_helper.rb

@@ -26,10 +26,6 @@ module EE
       end
     end
 
-    def epic_path(entity, *args)
-      group_epic_path(entity.group, entity, *args)
-    end
-
     def license_management_api_url(project)
       expose_path(api_v4_projects_managed_licenses_path(id: project.id))
     end
@@ -60,6 +56,11 @@ module EE
       end
     end
 
+    url_helper :epic
+    def epic_path(entity, *args)
+      group_epic_path(entity.group, entity, *args)
+    end
+
     url_helper :user_group_saml_omniauth_metadata
     def user_group_saml_omniauth_metadata_path(group)
       params = { group_path: group.path, token: group.saml_discovery_token }

ee/app/models/ee/epic.rb

@@ -16,6 +16,7 @@ module EE
       include UsageStatistics
       include FromUnion
       include EpicTreeSorting
+      include Presentable
 
       enum state_id: {
         opened: ::Epic.available_states[:opened],

ee/app/models/ee/issue.rb

@@ -204,6 +204,11 @@ module EE
       update!(blocking_issues_count: blocking_count)
     end
 
+    override :relocation_target
+    def relocation_target
+      super || promoted_to_epic
+    end
+
     private
 
     def blocking_issues_ids

ee/spec/features/projects/issues/viewing_relocated_issues_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'issues canonical link' do
+  include Spec::Support::Helpers::Features::CanonicalLinkHelpers
+
+  let(:epic) { create(:epic) }
+  let(:project) { create(:project, :public, group: epic.group) }
+  let(:original_issue) { create(:issue, project: project) }
+  let(:canonical_url) { epic_url(epic) }
+
+  context 'when the issue was promoted' do
+    it 'shows the canonical URL' do
+      original_issue.promoted_to_epic = epic
+      original_issue.save!
+
+      visit(issue_path(original_issue))
+
+      expect(page).to have_canonical_link(canonical_url)
+    end
+  end
+end

spec/features/projects/issues/viewing_relocated_issues_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'issues canonical link' do
+  include Spec::Support::Helpers::Features::CanonicalLinkHelpers
+
+  let_it_be(:original_project) { create(:project, :public) }
+  let_it_be(:original_issue)   { create(:issue, project: original_project) }
+  let_it_be(:canonical_issue)  { create(:issue) }
+  let_it_be(:canonical_url)    { issue_url(canonical_issue, Gitlab::Application.routes.default_url_options) }
+
+  it "doesn't show the canonical URL" do
+    visit(issue_path(original_issue))
+
+    expect(page).not_to have_any_canonical_links
+  end
+
+  context 'when the issue was moved' do
+    it 'shows the canonical URL' do
+      original_issue.moved_to = canonical_issue
+      original_issue.save!
+
+      visit(issue_path(original_issue))
+
+      expect(page).to have_canonical_link(canonical_url)
+    end
+  end
+
+  context 'when the issue was duplicated' do
+    it 'shows the canonical URL' do
+      original_issue.duplicated_to = canonical_issue
+      original_issue.save!
+
+      visit(issue_path(original_issue))
+
+      expect(page).to have_canonical_link(canonical_url)
+    end
+  end
+end

spec/support/helpers/features/canonical_link_helpers.rb

+# frozen_string_literal: true
+
+# These helpers allow you to manipulate with notes.
+#
+# Usage:
+#   describe "..." do
+#     include Spec::Support::Helpers::Features::CanonicalLinkHelpers
+#     ...
+#
+#     expect(page).to have_canonical_link(url)
+#
+module Spec
+  module Support
+    module Helpers
+      module Features
+        module CanonicalLinkHelpers
+          def have_canonical_link(url)
+            have_xpath("//link[@rel=\"canonical\" and @href=\"#{url}\"]", visible: false)
+          end
+
+          def have_any_canonical_links
+            have_xpath('//link[@rel="canonical"]', visible: false)
+          end
+        end
+      end
+    end
+  end
+end