template demonstrating that :if option in after_commit on: [event] triggered during other lifecycles

gistfile1.rb

begin
  require "bundler/inline"
rescue LoadError => e
  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
  raise e
end

gemfile(true) do
  source "https://rubygems.org"
  # Activate the gem you are reporting the issue against.
  gem "activerecord", "5.0.1"
  gem "sqlite3"
end

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

# Ensure backward compatibility with Minitest 4
Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)

# 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 :posts, force: true do |t|
  end

  create_table :comments, force: true do |t|
    t.integer :commentable_id
    t.string :commentable_type
  end
end

class Post < ActiveRecord::Base
  has_many :comments, as: :commentable, dependent: :destroy

  def bar
    'bar'
  end
end

class Comment < ActiveRecord::Base
  # Polymorphic association used to demonstrate when error might occur,
  # since it causes :commentable to be nil after destroy.
  belongs_to :commentable, polymorphic: true

  after_commit :do_something, on: [:create, :update], if: :foo?

  def foo?
    puts "\n***** Checking whether to do_something " \
         "(I am destroyed: #{destroyed?}) *****\n\n"
    STDOUT.flush
    commentable.bar == 'bar'
  end

  def do_something
    puts "\n***** do_something was performed *****\n\n"
    STDOUT.flush
  end
end

class BugTest < Minitest::Test
  def test_destroying_post_that_was_created
    post = Post.create!
    Comment.create!(commentable: post)
    post.destroy
    assert_equal(true, post.destroyed?)
  end
end