Require :as on opposite side of polymorphic associations

require 'bundler/inline'

gemfile do

  source 'https://rubygems.org'

  gem 'mongoid'

end

Tempfile.open(%w(config .yml)) do |f|

  uri = 'mongodb://mongo/test'

  f.write(<<~YAML)

development:

  clients:

    default:

      uri: #{uri}

  YAML

  f.flush

  Mongoid.load!(f.path, 'development')

  Mongoid::Clients.clients.each do |_, client|

    client.logger.level = Logger::ERROR

  end

end

class Parent

  include Mongoid::Document

  embeds_one :embedded_child

end

class EmbeddedChild

  include Mongoid::Document

  embedded_in :parent, polymorphic: true

end

EmbeddedChild.create!(parent: Parent.create!)

__END__

Mongoid::Errors::InvalidPath:

message:

  Having a root path assigned for EmbeddedChild is invalid.

summary:

  Mongoid has two different path objects for determining the location of a document in the database, Root and Embedded. This error is raised when an embedded document somehow gets a root path assigned.

resolution:

  Most likely your embedded model, EmbeddedChild is also referenced via a has_many from a root document in another collection. Double check the association definitions and fix any instances where embedded documents are improperly referenced from other collections.

from /usr/local/bundle/gems/mongoid-7.1.2/lib/mongoid/atomic/paths/root.rb:36:in `insert_modifier'