Factory_bot: Unable to reassign factory attribute defined as a sequence

[partydrone]

Description

I'm trying to write a simple test that validates the presence of an email attribute defined as a sequence in the factory, but the assignment fails and the email attribute retains its value.

Reproduction Steps

I have a factory that uses a sequence to set the email attribute on a user:

FactoryBot.define do
  factory :user do
    first_name { 'John' }
    last_name { 'Doe' }
    sequence(:email) { |n| "#{first_name}.#{last_name}.#{n}@example.com".downcase }
    password { 'password' }
  end
end

I can't assign email to a new value in my test:

require 'test_helper'
describe User do
  subject { build :user }

  it "must be a valid object" do
    _(subject).must_be :valid?
  end

  it "requires an email address" do
    subject.email = nil
    _(subject).wont_be :valid?
  end
end

Expected behavior

Within the test, I expect the value of subject.email to be nil when the assertion is evaluated.

Actual behavior

The value of subject.email is still the value assigned by the factory upon build (e.g., [email protected]) when the assertion is evaluated. In a pry session, I see something similar to this:

> subject.email
# "[email protected]"
> subject.email = nil
# nil
> subject.email
# "[email protected]"

System configuration

factory_bot version: 5.1.2
rails version: 4.2.11.1
ruby version: 2.4.9

[composerinteralia]

Hm, that doesn't ring any bells for me. Once the object is built, I can't think of any reason why factory_bot would affect how later attributes get assigned. Can you provide a reproduction script in this format: https://github.com/thoughtbot/factory_bot/blob/master/.github/REPRODUCTION_SCRIPT.rb

[composerinteralia]

I'm going to close this for now, since it is not something I can reproduce. But we can reopen it if you are able to provide a reproduction script. Thank you!

[partydrone]

Turns out someone overrode the writer method (def email=(value)) that had a guard clause in it for empty? values.