Adjusting some specs based on review

config/feature_flags/development/convert_diff_to_utf8_with_replacement_symbol.yml

 ---
 name: convert_diff_to_utf8_with_replacement_symbol
-introduced_by_url:
-rollout_issue_url:
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/79996
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/354526
 milestone: '14.9'
 type: development
 group: group::code review

lib/gitlab/git/diff.rb

@@ -158,9 +158,7 @@ module Gitlab
           raise "Invalid raw diff type: #{raw_diff.class}"
         end
 
-        if Feature.enabled?(:convert_diff_to_utf8_with_replacement_symbol, default_enabled: :yaml)
-          @diff = Gitlab::EncodingHelper.encode_utf8_with_replacement_character(@diff) if replace_invalid_utf8_chars && !detect_binary?(@diff)
-        end
+        encode_diff_to_utf8(replace_invalid_utf8_chars)
       end
 
       def to_hash
@@ -231,6 +229,13 @@ module Gitlab
 
       private
 
+      def encode_diff_to_utf8(replace_invalid_utf8_chars)
+        return unless Feature.enabled?(:convert_diff_to_utf8_with_replacement_symbol, default_enabled: :yaml)
+        return unless replace_invalid_utf8_chars && !detect_binary?(@diff)
+
+        @diff = Gitlab::EncodingHelper.encode_utf8_with_replacement_character(@diff)
+      end
+
       def init_from_hash(hash)
         raw_diff = hash.symbolize_keys
 

spec/lib/gitlab/git/diff_spec.rb

@@ -166,23 +166,44 @@ EOT
       let(:bad_string) { [0xae].pack("C*") }
       let(:bad_string_two) { [0x89].pack("C*") }
 
-      context 'when replace_invalid_utf8_chars is true' do
-        let(:diff) { described_class.new(@raw_diff_hash.merge({ diff: bad_string })) }
-        let(:diff_two) { described_class.new(@raw_diff_hash.merge({ diff: bad_string_two })) }
+      let(:diff) { described_class.new(@raw_diff_hash.merge({ diff: bad_string })) }
+      let(:diff_two) { described_class.new(@raw_diff_hash.merge({ diff: bad_string_two })) }
 
+      context 'when replace_invalid_utf8_chars is true' do
         it 'will convert invalid characters and not cause an encoding error' do
+          expect(diff.diff).to include(Gitlab::EncodingHelper::UNICODE_REPLACEMENT_CHARACTER)
+          expect(diff_two.diff).to include(Gitlab::EncodingHelper::UNICODE_REPLACEMENT_CHARACTER)
+
           expect { Oj.dump(diff) }.not_to raise_error(EncodingError)
           expect { Oj.dump(diff_two) }.not_to raise_error(EncodingError)
         end
+
+        context 'when the diff is binary' do
+          let(:project) { create(:project, :repository) }
+
+          it 'will not try to replace characters' do
+            expect(Gitlab::EncodingHelper).not_to receive(:encode_utf8_with_replacement_character?)
+            expect(binary_diff(project).diff).not_to be_empty
+          end
+        end
+
+        context 'when convert_diff_to_utf8_with_replacement_symbol feature flag is disabled' do
+          before do
+            stub_feature_flags(convert_diff_to_utf8_with_replacement_symbol: false)
+          end
+
+          it 'will not try to convert invalid characters' do
+            expect(Gitlab::EncodingHelper).not_to receive(:encode_utf8_with_replacement_character?)
+          end
+        end
       end
 
       context 'when replace_invalid_utf8_chars is false' do
-        let(:diff) { described_class.new(@raw_diff_hash.merge({ diff: bad_string }), replace_invalid_utf8_chars: false) }
-        let(:diff_two) { described_class.new(@raw_diff_hash.merge({ diff: bad_string_two }), replace_invalid_utf8_chars: false) }
+        let(:not_replaced_diff) { described_class.new(@raw_diff_hash.merge({ diff: bad_string, replace_invalid_utf8_chars: false }) ) }
+        let(:not_replaced_diff_two) { described_class.new(@raw_diff_hash.merge({ diff: bad_string_two, replace_invalid_utf8_chars: false }) ) }
 
-        it 'will not convert any invalid characters' do
-          expect(diff).not_to include(Gitlab::EncodingHelper::UNICODE_REPLACEMENT_CHARACTER)
-          expect(diff_two).not_to include(Gitlab::EncodingHelper::UNICODE_REPLACEMENT_CHARACTER)
+        it 'will not try to convert invalid characters' do
+          expect(Gitlab::EncodingHelper).not_to receive(:encode_utf8_with_replacement_character?)
         end
       end
     end
@@ -280,12 +301,11 @@ EOT
     let(:project) { create(:project, :repository) }
 
     it 'fake binary message when it detects binary' do
-      # Rugged will not detect this as binary, but we can fake it
       diff_message = "Binary files files/images/icn-time-tracking.pdf and files/images/icn-time-tracking.pdf differ\n"
-      binary_diff = described_class.between(project.repository, 'add-pdf-text-binary', 'add-pdf-text-binary^').first
 
-      expect(binary_diff.diff).not_to be_empty
-      expect(binary_diff.json_safe_diff).to eq(diff_message)
+      diff = binary_diff(project)
+      expect(diff.diff).not_to be_empty
+      expect(diff.json_safe_diff).to eq(diff_message)
     end
 
     it 'leave non-binary diffs as-is' do
@@ -399,4 +419,9 @@ EOT
       expect(diff.line_count).to eq(0)
     end
   end
+
+  def binary_diff(project)
+    # rugged will not detect this as binary, but we can fake it
+    described_class.between(project.repository, 'add-pdf-text-binary', 'add-pdf-text-binary^').first
+  end
 end