Merge branch '209912-commits-markdown-cache-preload' into 'master'

Preload commits markdown cache

See merge request gitlab-org/gitlab!35314

app/controllers/projects/merge_requests_controller.rb

@@ -109,8 +109,8 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
     # or from cache if already merged
     @commits =
       set_commits_for_rendering(
-        @merge_request.recent_commits.with_latest_pipeline(@merge_request.source_branch),
-          commits_count: @merge_request.commits_count
+        @merge_request.recent_commits.with_latest_pipeline(@merge_request.source_branch).with_markdown_cache,
+        commits_count: @merge_request.commits_count
       )
 
     render json: { html: view_to_html_string('projects/merge_requests/_commits') }

app/models/commit_collection.rb

@@ -53,6 +53,17 @@ class CommitCollection
     self
   end
 
+  # Returns the collection with markdown fields preloaded.
+  #
+  # Get the markdown cache from redis using pipeline to prevent n+1 requests
+  # when rendering the markdown of an attribute (e.g. title, full_title,
+  # description).
+  def with_markdown_cache
+    Commit.preload_markdown_cache!(commits)
+
+    self
+  end
+
   def unenriched
     commits.reject(&:gitaly_commit?)
   end

changelogs/unreleased/209912-commits-markdown-cache-preload.yml

+---
+title: Preload commits markdown cache
+merge_request: 35314
+author:
+type: performance

spec/models/commit_collection_spec.rb

@@ -75,6 +75,18 @@ RSpec.describe CommitCollection do
     end
   end
 
+  describe '#with_markdown_cache' do
+    let(:commits) { [commit] }
+    let(:collection) { described_class.new(project, commits) }
+
+    it 'preloads commits cache markdown' do
+      aggregate_failures do
+        expect(Commit).to receive(:preload_markdown_cache!).with(commits)
+        expect(collection.with_markdown_cache).to eq(collection)
+      end
+    end
+  end
+
   describe 'enrichment methods' do
     let(:gitaly_commit) { commit }
     let(:hash_commit) { Commit.from_hash(gitaly_commit.to_hash, project) }