Merge branch 'cache-max-user-access-name' into 'master'

Memoize the maximum access level for the author of notes

Cache the maximum access level for each user in a map in the controller
    
In #19273, we saw that retrieving ProjectTeam#human_max_access for each note takes the bulk of the time when rendering certain issues or merge requests. We observe that most of the comments in an issue are typically done by the same users. This MR memoizes the max access level by user ID.

See merge request !4982

app/helpers/notes_helper.rb

@@ -69,4 +69,14 @@ module NotesHelper
     button_tag 'Reply...', class: 'btn btn-text-field js-discussion-reply-button',
                            data: data, title: 'Add a reply'
   end
+
+  def note_max_access_for_user(note)
+    @max_access_by_user_id ||= Hash.new do |hash, key|
+      project = key[:project]
+      hash[key] = project.team.human_max_access(key[:user_id])
+    end
+
+    full_key = { project: note.project, user_id: note.author_id }
+    @max_access_by_user_id[full_key]
+  end
 end

app/views/projects/notes/_note.html.haml

@@ -17,7 +17,7 @@
           %a{ href: "##{dom_id(note)}" }
             = time_ago_with_tooltip(note.created_at, placement: 'bottom', html_class: 'note-created-ago')
         .note-actions
-          - access = note.project.team.human_max_access(note.author.id)
+          - access = note_max_access_for_user(note)
           - if access and not note.system
             %span.note-role.hidden-xs= access
           - if current_user and not note.system

spec/helpers/notes_helper_spec.rb

+require "spec_helper"
+
+describe NotesHelper do
+  describe "#notes_max_access_for_users" do
+    let(:owner) { create(:owner) }
+    let(:group) { create(:group) }
+    let(:project) { create(:empty_project, namespace: group) }
+    let(:master) { create(:user) }
+    let(:reporter) { create(:user) }
+    let(:guest) { create(:user) }
+
+    let(:owner_note) { create(:note, author: owner, project: project) }
+    let(:master_note) { create(:note, author: master, project: project) }
+    let(:reporter_note) { create(:note, author: reporter, project: project) }
+    let!(:notes) { [owner_note, master_note, reporter_note] }
+
+    before do
+      group.add_owner(owner)
+      project.team << [master, :master]
+      project.team << [reporter, :reporter]
+      project.team << [guest, :guest]
+    end
+
+    it 'return human access levels' do
+      original_method = project.team.method(:human_max_access)
+      expect_any_instance_of(ProjectTeam).to receive(:human_max_access).exactly(3).times do |*args|
+        original_method.call(args[1])
+      end
+
+      expect(helper.note_max_access_for_user(owner_note)).to eq('Owner')
+      expect(helper.note_max_access_for_user(master_note)).to eq('Master')
+      expect(helper.note_max_access_for_user(reporter_note)).to eq('Reporter')
+      # Call it again to ensure value is cached
+      expect(helper.note_max_access_for_user(owner_note)).to eq('Owner')
+    end
+
+    it 'handles access in different projects' do
+      second_project = create(:empty_project)
+      second_project.team << [master, :reporter]
+      other_note = create(:note, author: master, project: second_project)
+
+      expect(helper.note_max_access_for_user(master_note)).to eq('Master')
+      expect(helper.note_max_access_for_user(other_note)).to eq('Reporter')
+    end
+  end
+end