Optimize maximum user access level lookup in loading of notes

NotesHelper#note_editable? and ProjectTeam#human_max_access currently
take about 16% of the load time of an issue page. This MR preloads
the maximum access level of users for all notes in issues and merge
requests with several queries instead of one per user and caches
the result in RequestStore.

1 files changed, 31 insertions, 26 deletions

diff --git a/spec/helpers/notes_helper_spec.rb b/spec/helpers/notes_helper_spec.rb
index 08a93503258..af371248ae9 100644
--- a/spec/helpers/notes_helper_spec.rb
+++ b/spec/helpers/notes_helper_spec.rb
@@ -1,37 +1,30 @@
 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
+  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) }
 
-    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
+  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
+
+  describe "#notes_max_access_for_users" do
+    it 'return human access levels' do
       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
@@ -43,4 +36,16 @@ describe NotesHelper do
       expect(helper.note_max_access_for_user(other_note)).to eq('Reporter')
     end
   end
+
+  describe '#preload_max_access_for_authors' do
+    it 'loads multiple users' do
+      expected_access = {
+        owner.id => Gitlab::Access::OWNER,
+        master.id => Gitlab::Access::MASTER,
+        reporter.id => Gitlab::Access::REPORTER
+      }
+
+      expect(helper.preload_max_access_for_authors(notes, project)).to eq(expected_access)
+    end
+  end
 end