Why do my root nodes end up with themselves as the parent_id with acts_as_tree?

Question

I have an existing tree structure to which I'd like to add a new root and move the existing roots down one. I've written a rake task which works fine apart from one thing. The new root ends up with a parent_id which matches it's new id instead of NULL. The existing roots are successfully changed to have the new root as a parent. ``` # Rake task desc "Change categories to use new root" task :make_new_category_root => :environment do Company.all.each do |company| current_roots = company.root_categories new_root = Category.new(name: "New root") new_root.company = company new_root.parent = nil if new_root.save current_roots.each do |current| current.parent = new_root current.save end end end # Category class, abbreviated class Category < ActiveRecord::Base include ActsAsTree acts_as_tree :order => "name" belongs_to :company, touch: true validates :name, uniqueness: { scope: :company_id }, :if => :root? scope :roots, where(:parent_id => nil) end ```

Accepted Answer

I would need to see `Company#root_categories` to be sure, however I predict that `root_categories` in-fact includes `new_root`.

Is is due to the lazy evaluation of queries in Rails.

Try changing:

```
current_roots = company.root_categories
```

to:

```
current_roots = company.root_categories.all
```

Why do my root nodes end up with themselves as the parent_id with acts_as_tree?

Solution

Problem