Add search autocomplete suggestions for recently viewed epics

This implements the same thing we implemented for [issues](
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/40669
) and [merge requests](
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/42560
) now for Epics. This required a slightly different approach as the
`EpicsFinder` was not suitable for this purpose. At present it only
supports searching within a single group. And extending it to support
wider use cases would likely lead to performance issues as there is no
equivalent group permissions cache like `project_authorizations` table
to efficiently determine which groups a user can view epics in.

The simpler thing to do here was to just manually check the permissions
for each returned epic. This leaves a very edge case scenarion in which
a user was previously able to see an epic and looked at that epic in
their last 100 viewed epics and then performs a search and now only sees
4 suggestions (instead of the expected 5). This in theory, if the epic
was renamed and the new name contained something important the user
shouldn't see, could lead to the leak of an existence of that name in
the search results. Considering this edge case is so unlikely it seems
safe to not worry too much about it.

app/helpers/search_helper.rb

@@ -7,8 +7,7 @@ module SearchHelper
     return unless current_user
 
     resources_results = [
-      recent_merge_requests_autocomplete(term),
-      recent_issues_autocomplete(term),
+      recent_items_autocomplete(term),
       groups_autocomplete(term),
       projects_autocomplete(term)
     ].flatten
@@ -27,6 +26,10 @@ module SearchHelper
     end
   end
 
+  def recent_items_autocomplete(term)
+    recent_merge_requests_autocomplete(term) + recent_issues_autocomplete(term)
+  end
+
   def search_entries_info(collection, scope, term)
     return if collection.to_a.empty?
 

doc/user/search/index.md

@@ -209,7 +209,8 @@ You can also type in this search bar to see autocomplete suggestions for:
 - Project feature pages (try and type **milestones**)
 - Various settings pages (try and type **user settings**)
 - Recently viewed issues (try and type some word from the title of a recently viewed issue)
-- Recently viewed merge requests (try and type some word from the title of a recently merge request)
+- Recently viewed merge requests (try and type some word from the title of a recently viewed merge request)
+- Recently viewed epics (try and type some word from the title of a recently viewed epic)
 
 ## Basic search
 

ee/app/controllers/groups/epics_controller.rb

@@ -15,6 +15,7 @@ class Groups::EpicsController < Groups::ApplicationController
   before_action :authorize_update_issuable!, only: :update
   before_action :authorize_create_epic!, only: [:create, :new]
   before_action :verify_group_bulk_edit_enabled!, only: [:bulk_update]
+  after_action :log_epic_show, only: :show
 
   before_action do
     push_frontend_feature_flag(:vue_issuable_epic_sidebar, @group)
@@ -113,6 +114,12 @@ class Groups::EpicsController < Groups::ApplicationController
     @preload_for_collection ||= [:group, :author, :labels]
   end
 
+  def log_epic_show
+    return unless current_user && @epic
+
+    ::Gitlab::Search::RecentEpics.new(user: current_user).log_view(@epic)
+  end
+
   def authorize_create_epic!
     return render_404 unless can?(current_user, :create_epic, group)
   end

ee/app/helpers/ee/search_helper.rb

@@ -19,6 +19,11 @@ module EE
       options
     end
 
+    override :recent_items_autocomplete
+    def recent_items_autocomplete(term)
+      super + recent_epics_autocomplete(term)
+    end
+
     override :search_blob_title
     def search_blob_title(project, path)
       if @project
@@ -72,6 +77,20 @@ module EE
 
     private
 
+    def recent_epics_autocomplete(term)
+      return [] unless current_user
+
+      ::Gitlab::Search::RecentEpics.new(user: current_user).search(term).map do |e|
+        {
+          category: "Recent epics",
+          id: e.id,
+          label: search_result_sanitize(e.title),
+          url: epic_path(e),
+          avatar_url: e.group.avatar_url || ''
+        }
+      end
+    end
+
     def search_multiple_assignees?(type)
       context = @project.presence || @group.presence || :dashboard
 

ee/app/models/ee/epic.rb

@@ -17,6 +17,7 @@ module EE
       include FromUnion
       include EpicTreeSorting
       include Presentable
+      include IdInOrdered
 
       enum state_id: {
         opened: ::Epic.available_states[:opened],

ee/changelogs/unreleased/259608-add-autocomplete-suggestions-for-epics.yml

+---
+title: Add search autocomplete suggestions for recently viewed epics
+merge_request: 43964
+author:
+type: added

ee/lib/gitlab/search/recent_epics.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Search
+    class RecentEpics < RecentItems
+      extend ::Gitlab::Utils::Override
+
+      override :search
+      # rubocop: disable CodeReuse/ActiveRecord
+      def search(term)
+        epics = Epic.full_search(term, matched_columns: 'title')
+          .id_in_ordered(latest_ids).limit(::Gitlab::Search::RecentItems::SEARCH_LIMIT)
+
+        # Since EpicsFinder does not support searching globally (ie. applying
+        # global permissions) the most efficient option is just to load the
+        # last 5 matching recently viewed epics and then do an explicit
+        # permissions check
+        disallowed = epics.reject { |epic| Ability.allowed?(user, :read_epic, epic) }
+
+        return epics if disallowed.empty?
+
+        epics.where.not(id: disallowed.map(&:id))
+      end
+      # rubocop: enable CodeReuse/ActiveRecord
+
+      private
+
+      def type
+        Epic
+      end
+    end
+  end
+end

ee/spec/controllers/groups/epics_controller_spec.rb

@@ -285,6 +285,18 @@ RSpec.describe Groups::EpicsController do
           expect(response).to render_template 'groups/epics/show'
         end
 
+        it 'logs the view with Gitlab::Search::RecentEpics' do
+          group.add_developer(user)
+
+          recent_epics_double = instance_double(::Gitlab::Search::RecentEpics, log_view: nil)
+          expect(::Gitlab::Search::RecentEpics).to receive(:new).with(user: user).and_return(recent_epics_double)
+
+          show_epic
+
+          expect(response).to be_successful
+          expect(recent_epics_double).to have_received(:log_view).with(epic)
+        end
+
         context 'with unauthorized user' do
           it 'returns a not found 404 response' do
             show_epic

ee/spec/helpers/search_helper_spec.rb

@@ -51,6 +51,47 @@ RSpec.describe SearchHelper do
     end
   end
 
+  describe 'search_autocomplete_opts' do
+    context "with a user" do
+      let(:user) { create(:user) }
+
+      before do
+        allow(self).to receive(:current_user).and_return(user)
+      end
+
+      it 'includes the users recently viewed epics' do
+        recent_epics = instance_double(::Gitlab::Search::RecentEpics)
+        expect(::Gitlab::Search::RecentEpics).to receive(:new).with(user: user).and_return(recent_epics)
+        group1 = create(:group, :public, :with_avatar)
+        group2 = create(:group, :public)
+        epic1 = create(:epic, title: 'epic 1', group: group1)
+        epic2 = create(:epic, title: 'epic 2', group: group2)
+
+        expect(recent_epics).to receive(:search).with('the search term').and_return(Epic.id_in_ordered([epic1.id, epic2.id]))
+
+        results = search_autocomplete_opts("the search term")
+
+        expect(results.count).to eq(2)
+
+        expect(results[0]).to include({
+          category: 'Recent epics',
+          id: epic1.id,
+          label: 'epic 1',
+          url: Gitlab::Routing.url_helpers.group_epic_path(epic1.group, epic1),
+          avatar_url: group1.avatar_url
+        })
+
+        expect(results[1]).to include({
+          category: 'Recent epics',
+          id: epic2.id,
+          label: 'epic 2',
+          url: Gitlab::Routing.url_helpers.group_epic_path(epic2.group, epic2),
+          avatar_url: '' # This group didn't have an avatar so set this to ''
+        })
+      end
+    end
+  end
+
   describe '#project_autocomplete' do
     let(:user) { create(:user) }
 

ee/spec/lib/gitlab/search/recent_epics_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe ::Gitlab::Search::RecentEpics do
+  let(:parent_type) { :group }
+
+  def create_item(content:, parent:)
+    create(:epic, title: content, group: parent)
+  end
+
+  before do
+    stub_licensed_features(epics: true)
+  end
+
+  it_behaves_like 'search recent items'
+end

spec/helpers/search_helper_spec.rb

@@ -73,7 +73,7 @@ RSpec.describe SearchHelper do
         expect(result.keys).to match_array(%i[category id label url avatar_url])
       end
 
-      it 'includes the users recent issues' do
+      it 'includes the users recently viewed issues' do
         recent_issues = instance_double(::Gitlab::Search::RecentIssues)
         expect(::Gitlab::Search::RecentIssues).to receive(:new).with(user: user).and_return(recent_issues)
         project1 = create(:project, :with_avatar, namespace: user.namespace)
@@ -104,7 +104,7 @@ RSpec.describe SearchHelper do
         })
       end
 
-      it 'includes the users recent merge requests' do
+      it 'includes the users recently viewed merge requests' do
         recent_merge_requests = instance_double(::Gitlab::Search::RecentMergeRequests)
         expect(::Gitlab::Search::RecentMergeRequests).to receive(:new).with(user: user).and_return(recent_merge_requests)
         project1 = create(:project, :with_avatar, namespace: user.namespace)