Add project export presenter

- Clean streaming serializer
- Clean TreeSaver

app/presenters/projects/import_export/project_export_presenter.rb

+# frozen_string_literal: true
+
+module Projects
+  module ImportExport
+    class ProjectExportPresenter < Gitlab::View::Presenter::Delegated
+      presents :project
+
+      def project_members
+        group_members.as_json(group_members_tree).each do |group_member|
+          group_member['source_type'] = 'Project' # Make group members project members of the future import
+        end
+      end
+
+      def as_json(*_args)
+        self.respond_to?(:override_description) ? super.merge("description" => override_description) : super
+      end
+
+      private
+
+      # rubocop: disable CodeReuse/ActiveRecord
+      def group_members
+        return [] unless current_user.can?(:admin_group, project.group)
+        # We need `.where.not(user_id: nil)` here otherwise when a group has an
+        # invitee, it would make the following query return 0 rows since a NULL
+        # user_id would be present in the subquery
+        # See http://stackoverflow.com/questions/129077/not-in-clause-and-null-values
+        non_null_user_ids = project.project_members.where.not(user_id: nil).select(:user_id)
+        GroupMembersFinder.new(project.group).execute.where.not(user_id: non_null_user_ids)
+      end
+      # rubocop: enable CodeReuse/ActiveRecord
+    end
+  end
+end

lib/gitlab/import_export/json/streaming_serializer.rb

@@ -6,9 +6,6 @@ module Gitlab
       class StreamingSerializer
         include Gitlab::ImportExport::CommandLineUtil
 
-        attr_reader :overrides
-        attr_reader :additional_relations
-
         BATCH_SIZE = 100
 
         class Raw < String
@@ -20,9 +17,7 @@ module Gitlab
         def initialize(exportable, relations_schema, json_writer)
           @exportable = exportable
           @relations_schema = relations_schema
-          @overrides = {}
           @json_writer = json_writer
-          @additional_relations = {}
         end
 
         def execute
@@ -40,10 +35,7 @@ module Gitlab
         def serialize_root
           attributes = exportable.as_json(
             relations_schema.merge(include: nil, preloads: nil))
-
-          data = attributes.merge(overrides)
-
-          json_writer.set(data)
+          json_writer.set(attributes)
         end
 
         def serialize_relation(definition)
@@ -54,7 +46,6 @@ module Gitlab
           options = definition.first.second
 
           record = exportable.public_send(key) # rubocop: disable GitlabSecurity/PublicSend
-
           if record.is_a?(ActiveRecord::Relation)
             serialize_many_relations(key, record, options)
           else
@@ -74,12 +65,6 @@ module Gitlab
               json_writer.append(key, item)
             end
           end
-
-          additional_relations[key].to_a.each do |item|
-            item = Raw.new(item.to_json(options))
-
-            json_writer.append(key, item)
-          end
         end
 
         def serialize_single_relation(key, record, options)

lib/gitlab/import_export/project/tree_saver.rb

@@ -17,15 +17,13 @@ module Gitlab
         def save
           json_writer = ImportExport::JSON::LegacyWriter.new(File.join(@shared.export_path, "project.json"))
 
-          serializer = ImportExport::JSON::StreamingSerializer.new(@project, reader.project_tree, json_writer)
-          serializer.overrides['description'] = @params[:description] if @params[:description].present?
-          serializer.additional_relations['project_members'] = group_members_array
+          serializer = ImportExport::JSON::StreamingSerializer.new(exportable, reader.project_tree, json_writer)
           serializer.execute
 
           true
-        #rescue => e
-        #  @shared.error(e)
-        #  false
+        rescue => e
+          @shared.error(e)
+          false
         ensure
           json_writer&.close
         end
@@ -36,22 +34,22 @@ module Gitlab
           @reader ||= Gitlab::ImportExport::Reader.new(shared: @shared)
         end
 
-        def group_members_array
-          group_members.as_json(reader.group_members_tree).each do |group_member|
-            group_member['source_type'] = 'Project' # Make group members project members of the future import
-          end
+        def exportable
+          @project.present(exportable_params)
         end
 
-        def group_members
-          return [] unless @current_user.can?(:admin_group, @project.group)
-
-          # We need `.where.not(user_id: nil)` here otherwise when a group has an
-          # invitee, it would make the following query return 0 rows since a NULL
-          # user_id would be present in the subquery
-          # See http://stackoverflow.com/questions/129077/not-in-clause-and-null-values
-          non_null_user_ids = @project.project_members.where.not(user_id: nil).select(:user_id)
+        def exportable_params
+          params = {
+          presenter_class: presenter_class,
+            current_user: @current_user,
+            group_members_tree: reader.group_members_tree
+          }
+          params[:override_description] = @params[:description] if @params[:description]
+          params
+        end
 
-          GroupMembersFinder.new(@project.group).execute.where.not(user_id: non_null_user_ids)
+        def presenter_class
+          Projects::ImportExport::ProjectExportPresenter
         end
       end
     end