Include submodule information for files in diff metadata

app/serializers/diff_file_metadata_entity.rb

@@ -7,6 +7,7 @@ class DiffFileMetadataEntity < Grape::Entity
   expose :old_path
   expose :new_file?, as: :new_file
   expose :deleted_file?, as: :deleted_file
+  expose :submodule?, as: :submodule
   expose :file_identifier_hash
   expose :file_hash
 end

changelogs/unreleased/285287-include-submodule-information-for-files-in-diff-metadata.yml

+---
+title: Include submodule information for files in diff metadata
+merge_request: 50346
+author: Simon Stieger @sim0
+type: fixed

spec/serializers/diff_file_metadata_entity_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe DiffFileMetadataEntity do
+  let(:merge_request) { create(:merge_request_with_diffs) }
+  let(:raw_diff_file) { merge_request.merge_request_diff.diffs.raw_diff_files.first }
+  let(:entity) { described_class.new(raw_diff_file) }
+
+  context 'as json' do
+    subject { entity.as_json }
+
+    it 'exposes the expected fields' do
+      expect(subject.keys).to contain_exactly(
+        :added_lines,
+        :removed_lines,
+        :new_path,
+        :old_path,
+        :new_file,
+        :deleted_file,
+        :submodule,
+        :file_identifier_hash,
+        :file_hash
+      )
+    end
+  end
+end