Merge branch 'sh-speed-up-commit-loading' into 'master'

Speed up commit loads by disabling BatchLoader replace_methods

See merge request gitlab-org/gitlab-ce!29633

app/models/commit.rb

@@ -94,7 +94,7 @@ class Commit
     end
 
     def lazy(project, oid)
-      BatchLoader.for({ project: project, oid: oid }).batch do |items, loader|
+      BatchLoader.for({ project: project, oid: oid }).batch(replace_methods: false) do |items, loader|
         items_by_project = items.group_by { |i| i[:project] }
 
         items_by_project.each do |project, commit_ids|

changelogs/unreleased/sh-speed-up-commit-loading.yml

+---
+title: Speed up commit loads by disabling BatchLoader replace_methods
+merge_request: 29633
+author:
+type: performance

spec/models/commit_spec.rb

@@ -44,6 +44,14 @@ describe Commit do
           expect(commit.id).to eq(oids[i])
         end
       end
+
+      it 'does not attempt to replace methods via BatchLoader' do
+        subject.each do |commit|
+          expect(commit).to receive(:method_missing).and_call_original
+
+          commit.id
+        end
+      end
     end
 
     context 'when not found' do