Disable method replacement in avatar loading

We've seen a significant performance penalty when using
`BatchLoader#__replace_with!`. This defines methods on the batch loader
that proxy to the 'real' object using send. The alternative is
`method_missing`, which is slower.  However, we've noticed that
`method_missing` can be faster if:

1. The objects being loaded have a large interface.
2. We don't call too many methods on the loaded object.

Avatar uploads meet both criteria above, so let's use the newly-released
feature in https://github.com/exAspArk/batch-loader/pull/45.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/60903

1 files changed, 8 insertions, 0 deletions

diff --git a/spec/uploaders/object_storage_spec.rb b/spec/uploaders/object_storage_spec.rb
index 9ce9a353913..a62830c35f1 100644
--- a/spec/uploaders/object_storage_spec.rb
+++ b/spec/uploaders/object_storage_spec.rb
@@ -771,6 +771,14 @@ describe ObjectStorage do
           expect { avatars }.not_to exceed_query_limit(1)
         end
 
+        it 'does not attempt to replace methods' do
+          models.each do |model|
+            expect(model.avatar.upload).to receive(:method_missing).and_call_original
+
+            model.avatar.upload.path
+          end
+        end
+
         it 'fetches a unique upload for each model' do
           expect(avatars.map(&:url).uniq).to eq(avatars.map(&:url))
           expect(avatars.map(&:upload).uniq).to eq(avatars.map(&:upload))