Fix project transfer with hashed-storage attachments

app/services/projects/transfer_service.rb

@@ -67,7 +67,7 @@ module Projects
         Labels::TransferService.new(current_user, @old_group, project).execute
         # Move uploads
-        Gitlab::UploadsTransfer.new.move_project(project.path, @old_namespace.full_path, @new_namespace.full_path)
+        move_project_uploads(project)
         # Move pages
         Gitlab::PagesTransfer.new.move_project(project.path, @old_namespace.full_path, @new_namespace.full_path)
@@ -139,5 +139,15 @@ module Projects
       # Move wiki repo also if present
       move_repo_folder("#{@old_path}.wiki", "#{@new_path}.wiki")
     end
+
+    def move_project_uploads(project)
+      return if project.hashed_storage?(:attachments)
+
+      Gitlab::UploadsTransfer.new.move_project(
+        project.path,
+        @old_namespace.full_path,
+        @new_namespace.full_path
+      )
+    end
   end
 end