1 files changed, 8 insertions, 5 deletions
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index cd5b345bae5..082adcafcc8 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -179,10 +179,11 @@ class MergeRequest < ActiveRecord::Base
     work_in_progress?(title) ? title : "WIP: #{title}"
   end
 
-  def to_reference(from_project = nil, full: false)
+  # `from` argument can be a Namespace or Project.
+  def to_reference(from = nil, full: false)
     reference = "#{self.class.reference_prefix}#{iid}"
 
-    "#{project.to_reference(from_project, full: full)}#{reference}"
+    "#{project.to_reference(from, full: full)}#{reference}"
   end
 
   def first_commit
@@ -865,9 +866,11 @@ class MergeRequest < ActiveRecord::Base
       paths: paths
     )
 
-    active_diff_notes.each do |note|
-      service.execute(note)
-      Gitlab::Timeless.timeless(note, &:save)
+    transaction do
+      active_diff_notes.each do |note|
+        service.execute(note)
+        Gitlab::Timeless.timeless(note, &:save)
+      end
     end
   end