Fails to duplicate descendants of polymorphic relations

[Benoit-Baumann]

Hi @hopsoft !

First of all, thanks for this awesome gem !

I'm facing a problem while trying to duplicate a record with complexe associations. I have the following models (simplified):

class ContentPage < ApplicationRecord
  has_many :content_page_blocks, inverse_of: :content_page, dependent: :destroy
end

class ContentPageBlock < ApplicationRecord
  belongs_to :content_page
  belongs_to :blockable, polymorphic: true, dependent: :destroy, inverse_of: :content_page_block
end

class CardBlock < ApplicationRecord
  has_one :content_page_block, as: :blockable, dependent: :destroy, inverse_of: :blockable
  accepts_nested_attributes_for :content_page_block, allow_destroy: true

  has_one :content_page, through: :content_page_block

  has_many :cards class_name: "ContentPageCard", inverse_of: :card_block, dependent: :destroy
end

# more ApplicationRecord models for other blocks...

My goal is to duplicate a content page with all its descendants.

options = {
  include_keys: false,
  include_timestamps: false,
  include_unsaved_changes: false,
  include_descendants: true,
  descendant_depth: 10
}

content_page = ContentPage.first
=> #<ContentPage:0x0000000108fdae68
   id: 1,
   name: "First ContentPage">

# load descendants into memory
content_page.content_page_blocks.map(&:blockable)

content_page.content_page_blocks.first
=> #<ContentPageBlock:0x00000001096c8a90
   id: 1,
   content_page_id: 1,
   blockable_type: "CardBlock",
   blockable_id: 1>

content_page.content_page_blocks.first.blockable
=> #<CardBlock:0x000000010978b860
   id: 1,
   title: "First CardBlock">

encoded = URI::UID.build(content_page, options).to_s
content_page_dup = URI::UID.parse(encoded).decode

content_page_dup
=> #<ContentPage:0x00000001089c8e58
   id: nil,
   name: "First ContentPage">
# the content page is correctly duplicated 🥳

content_page_dup.content_page_blocks.first
=> #<ContentPageBlock:0x0000000108a30918
   id: nil,
   content_page_id: nil,
   blockable_type: "CardBlock",
   blockable_id: nil>
# the content page block is correctly duplicated as well 🥳

content_page_dup.content_page_blocks.first.content_page == content_page_dup
=> true # and it's correctly associated to the duplicated content page 🥳

content_page_dup.content_page_blocks.first.blockable
=> nil # it should be a new instance of CardBlock but it is nil... 😕

As you can see, the gem fails to duplicate the polymorphic association blockable of the ContentPageBlock model.

FYI, I'm encoutering the same problem with models that have has_many_attached and has_one_attached associations.

Thanks for your help !

[hopsoft]

Thanks for the report. I definitely want to expand on the current "simple" descendant support and tackle other types of associations soon.