Enable FindCommit caching for project and commits pages

This reduces a handful of duplicate FindCommit calls while viewing the
projects and commits pages.

app/controllers/projects/commits_controller.rb

@@ -14,6 +14,8 @@ class Projects::CommitsController < Projects::ApplicationController
   before_action :validate_ref!, except: :commits_root
   before_action :set_commits, except: :commits_root
 
+  around_action :allow_gitaly_ref_name_caching
+
   def commits_root
     redirect_to project_commits_path(@project, @project.default_branch)
   end

app/controllers/projects_controller.rb

@@ -26,6 +26,8 @@ class ProjectsController < Projects::ApplicationController
   before_action :authorize_admin_project!, only: [:edit, :update, :housekeeping, :download_export, :export, :remove_export, :generate_new_export]
   before_action :event_filter, only: [:show, :activity]
 
+  around_action :allow_gitaly_ref_name_caching, only: [:index, :show]
+
   layout :determine_layout
 
   def index

changelogs/unreleased/allow-ref-name-caching-projects-controller.yml

+---
+title: Enable FindCommit caching for project and commits pages
+merge_request: 27048
+author:
+type: performance

spec/controllers/projects/commits_controller_spec.rb

@@ -113,6 +113,8 @@ describe Projects::CommitsController do
       render_views
 
       before do
+        expect(::Gitlab::GitalyClient).to receive(:allow_ref_name_caching).and_call_original unless id.include?(' ')
+
         get(:signatures,
             params: {
               namespace_id: project.namespace,

spec/controllers/projects_controller_spec.rb

@@ -78,6 +78,10 @@ describe ProjectsController do
       end
 
       context "user has access to project" do
+        before do
+          expect(::Gitlab::GitalyClient).to receive(:allow_ref_name_caching).and_call_original
+        end
+
         context "and does not have notification setting" do
           it "initializes notification as disabled" do
             get :show, params: { namespace_id: public_project.namespace, id: public_project }