1 files changed, 37 insertions, 0 deletions
diff --git a/app/models/preloaders/project_root_ancestor_preloader.rb b/app/models/preloaders/project_root_ancestor_preloader.rb
new file mode 100644
index 00000000000..8d04e71774c
--- /dev/null
+++ b/app/models/preloaders/project_root_ancestor_preloader.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+module Preloaders
+  class ProjectRootAncestorPreloader
+    def initialize(projects, namespace_sti_name = :namespace, root_ancestor_preloads = [])
+      @projects = projects
+      @namespace_sti_name = namespace_sti_name
+      @root_ancestor_preloads = root_ancestor_preloads
+    end
+
+    def execute
+      return if @projects.is_a?(ActiveRecord::NullRelation)
+      return unless ::Feature.enabled?(:use_traversal_ids)
+
+      root_query = Namespace.joins("INNER JOIN (#{join_sql}) as root_query ON root_query.root_id = namespaces.id")
+                        .select('namespaces.*, root_query.id as source_id')
+
+      root_query = root_query.preload(*@root_ancestor_preloads) if @root_ancestor_preloads.any?
+
+      root_ancestors_by_id = root_query.group_by(&:source_id)
+
+      ActiveRecord::Associations::Preloader.new.preload(@projects, :namespace)
+      @projects.each do |project|
+        project.namespace.root_ancestor = root_ancestors_by_id[project.id]&.first
+      end
+    end
+
+    private
+
+    def join_sql
+      @projects
+        .joins(@namespace_sti_name)
+        .select('projects.id, namespaces.traversal_ids[1] as root_id')
+        .to_sql
+    end
+  end
+end