1 files changed, 21 insertions, 3 deletions

diff --git a/lib/gitlab/import_export/relation_factory.rb b/lib/gitlab/import_export/relation_factory.rb
index 4a41a69840b..c5cf290f191 100644
--- a/lib/gitlab/import_export/relation_factory.rb
+++ b/lib/gitlab/import_export/relation_factory.rb
@@ -18,9 +18,10 @@ module Gitlab
                     label: :project_label,
                     custom_attributes: 'ProjectCustomAttribute',
                     project_badges: 'Badge',
+                    metrics: 'MergeRequest::Metrics',
                     ci_cd_settings: 'ProjectCiCdSetting' }.freeze
 
-      USER_REFERENCES = %w[author_id assignee_id updated_by_id user_id created_by_id last_edited_by_id merge_user_id resolved_by_id closed_by_id].freeze
+      USER_REFERENCES = %w[author_id assignee_id updated_by_id merged_by_id latest_closed_by_id user_id created_by_id last_edited_by_id merge_user_id resolved_by_id closed_by_id].freeze
 
       PROJECT_REFERENCES = %w[project_id source_project_id target_project_id].freeze
 
@@ -36,13 +37,30 @@ module Gitlab
         new(*args).create
       end
 
-      def initialize(relation_sym:, relation_hash:, members_mapper:, user:, project:)
+      def self.relation_class(relation_name)
+        # There are scenarios where the model is pluralized (e.g.
+        # MergeRequest::Metrics), and we don't want to force it to singular
+        # with #classify.
+        relation_name.to_s.classify.constantize
+      rescue NameError
+        relation_name.to_s.constantize
+      end
+
+      def initialize(relation_sym:, relation_hash:, members_mapper:, user:, project:, excluded_keys: [])
         @relation_name = OVERRIDES[relation_sym] || relation_sym
         @relation_hash = relation_hash.except('noteable_id')
         @members_mapper = members_mapper
         @user = user
         @project = project
         @imported_object_retries = 0
+
+        # Remove excluded keys from relation_hash
+        # We don't do this in the parsed_relation_hash because of the 'transformed attributes'
+        # For example, MergeRequestDiffFiles exports its diff attribute as utf8_diff. Then,
+        # in the create method that attribute is renamed to diff. And because diff is an excluded key,
+        # if we clean the excluded keys in the parsed_relation_hash, it will be removed
+        # from the object attributes and the export will fail.
+        @relation_hash.except!(*excluded_keys)
       end
 
       # Creates an object from an actual model with name "relation_sym" with params from
@@ -187,7 +205,7 @@ module Gitlab
       end
 
       def relation_class
-        @relation_class ||= @relation_name.to_s.classify.constantize
+        @relation_class ||= self.class.relation_class(@relation_name)
       end
 
       def imported_object