inverse_of breaks association.build

test.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  # Activate the gem you are reporting the issue against.
  gem "activerecord", "5.2.2"
  gem "sqlite3", "~> 1.3.6"
end

require "active_record"
require "minitest/autorun"
require "logger"

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :users, force: true do |t|
  end

  create_table :ownerships, force: true do |t|
    t.integer :user_id
    t.string :resource_type
    t.integer :resource_id
  end

  create_table :articles, force: true do |t|
  end
end

class User < ActiveRecord::Base
  has_many :ownerships
  has_many :articles, through: :ownerships, source: :resource, source_type: "Article"
end

class Ownership < ActiveRecord::Base
  belongs_to :user
  belongs_to :resource, polymorphic: true, inverse_of: :ownerships
end

class Article < ActiveRecord::Base
  has_many :ownerships, as: :resource
  has_many :owners, through: :ownerships, source: :user
end


class BugTest < Minitest::Test
  def test_association_stuff
    user = User.create!
    user.articles.build
  end
end