Hopefully this works

lib/gitlab/git/repository.rb

@@ -456,7 +456,7 @@ module Gitlab
       def ref_name_for_sha(ref_path, sha)
         Gitlab::GitalyClient.migrate(:find_ref_name) do |is_enabled|
           if is_enabled
-            Gitlab::GitalyClient::Ref.find_ref_name(self, sha, ref_path)
+            gitaly_ref_client.find_ref_name(sha, ref_path)
           else
             args = %W(#{Gitlab.config.git.bin_path} for-each-ref --count=1 #{ref_path} --contains #{sha})
 

spec/models/environment_spec.rb

@@ -116,7 +116,7 @@ describe Environment, models: true do
       end
 
       it 'calls GitalyClient' do
-        expect(Gitlab::GitalyClient::Ref).to receive(:find_ref_name).with(project.repository.raw_repository, commit.id, environment.ref_path)
+        expect_any_instance_of(Gitlab::GitalyClient::Ref).to receive(:find_ref_name)
 
         environment.first_deployment_for(commit)
       end