Traits possible race condition when creating dependent associations

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"
  git_source(:github) { |repo| "https://github.com/#{repo}.git" }
  gem "factory_bot", "~> 6.0"
  gem "activerecord"
  gem "sqlite3"
end

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

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|
    t.integer :role, default: 0
    t.string :some_value
  end

  create_table :addresses, force: true do |t|
    t.references :user, null: false, foreign_key: true
  end
end

class User < ActiveRecord::Base
  enum role: %i[user admin]

  has_one :address

  validates_presence_of :some_value, if: :admin?
end

class Address < ActiveRecord::Base
  belongs_to :user
end

FactoryBot.define do
  factory :user do
    role { :user }

    address { association(:address, user: instance) }

    trait :admin do
      role { :admin }
      some_value { 'present' }
    end
  end

  factory :address do
    user
  end
end

class FactoryBotTest < Minitest::Test
  def test_factory_bot_stuff
    user = FactoryBot.create(:user, :admin)

    assert user.persisted?
  end
end

# Run the tests with `ruby <filename>`

1. Create a main model with a conditional presence validation

class User
  enum role: %I[user admin]
  
  validates_presence_of :some_value, if: :admin?
end

2. Create a second model linked to the First model

class User
# ...
  has_one :address
# ...
end

class Address
  belongs_to :user
end

3. Create a factory with a trait to validate the given condition

FactoryBot.define do
  factory :user do
    role { :user }

    address { association(:address, user: instance) }

    trait :admin do
      role { :admin }
      some_value { 'present' }
    end
  end
end

4. Create a simple factory for the second model

FactoryBot.define do
  factory :address do
    user { association(:user, address: instance) }
  end
end

5. Add some simple specs

require 'rails_helper'

RSpec.describe User, type: :model do
  context 'without trait' do
    it 'builds' do
      expect(build(:user)).to be_valid
    end

    it 'creates' do
      expect(create(:user)).to be_persisted
    end
  end

  context 'with admin trait' do
    it 'builds' do
      expect(build(:user, :admin)).to be_valid
    end

    # this will fail
    it 'creates' do
      expect(create(:user, :admin)).to be_persisted
    end
  end
end

6. Run specs

rails db:migrate
bundle exec rspec