Optimise import performanceoptimise-import-performance

- Fix `O(n)` complexity of `append_or_update_attribute`,
  we append objects to an array and re-save project
- Remove the usage of `keys.include?` as it performs `O(n)`
  search, instead use `.has_key?`
- Remove the usage of `.keys.first` as it performs a copy
  of all keys, instead use `.first.first`

4 files changed, 4 insertions, 4 deletions

diff --git a/lib/gitlab/import_export/attributes_finder.rb b/lib/gitlab/import_export/attributes_finder.rb
index 409243e68a5..42cd94add79 100644
--- a/lib/gitlab/import_export/attributes_finder.rb
+++ b/lib/gitlab/import_export/attributes_finder.rb
@@ -45,7 +45,7 @@ module Gitlab
       end
 
       def key_from_hash(value)
-        value.is_a?(Hash) ? value.keys.first : value
+        value.is_a?(Hash) ? value.first.first : value
       end
     end
   end
diff --git a/lib/gitlab/import_export/json_hash_builder.rb b/lib/gitlab/import_export/json_hash_builder.rb
index b145f37c052..a92e3862361 100644
--- a/lib/gitlab/import_export/json_hash_builder.rb
+++ b/lib/gitlab/import_export/json_hash_builder.rb
@@ -27,7 +27,7 @@ module Gitlab
       #   {:merge_requests=>[:merge_request_diff, :notes]}
       def process_model_objects(model_object_hash)
         json_config_hash = {}
-        current_key = model_object_hash.keys.first
+        current_key = model_object_hash.first.first
 
         model_object_hash.values.flatten.each do |model_object|
           @attributes_finder.parse(current_key) { |hash| json_config_hash[current_key] ||= hash }
diff --git a/lib/gitlab/import_export/members_mapper.rb b/lib/gitlab/import_export/members_mapper.rb
index a154de5419e..71e9064c5fd 100644
--- a/lib/gitlab/import_export/members_mapper.rb
+++ b/lib/gitlab/import_export/members_mapper.rb
@@ -35,7 +35,7 @@ module Gitlab
       end
 
       def include?(old_author_id)
-        map.keys.include?(old_author_id) && map[old_author_id] != default_user_id
+        map.has_key?(old_author_id) && map[old_author_id] != default_user_id
       end
 
       private
diff --git a/lib/gitlab/import_export/relation_factory.rb b/lib/gitlab/import_export/relation_factory.rb
index 1b545b1d049..0be49e27acb 100644
--- a/lib/gitlab/import_export/relation_factory.rb
+++ b/lib/gitlab/import_export/relation_factory.rb
@@ -185,7 +185,7 @@ module Gitlab
         return unless EXISTING_OBJECT_CHECK.include?(@relation_name)
         return unless @relation_hash['group_id']
 
-        @relation_hash['group_id'] = @project.group&.id
+        @relation_hash['group_id'] = @project.namespace_id
       end
 
       def reset_tokens!