JoshCheek

# Config
require 'rails'
require 'ar_lazy_preload' # https://github.com/DmitryTsepelev/ar_lazy_preload
require 'active_record'
ActiveRecord::Base.establish_connection adapter: 'sqlite3', database: ':memory:'

# not sure where this is supposed to happen, but it's necessary b/c ar_lazy_preload
# adds its functionality in a callback after active record finishes loading.
ArLazyPreload::Railtie.config.to_prepare_blocks.each(&:call)

JoshCheek

# Config
require 'active_record'
ActiveRecord::Base.establish_connection adapter: 'sqlite3', database: ':memory:'

# Migrations
ActiveRecord::Schema.define do
  self.verbose = false
  create_table(:users) { |t| t.string :name }
  create_table :posts do |t|
    t.string :name

JoshCheek

gem 'cancancan', '= 2.1.2' # the version from our gemfile
require 'cancan'

module CanCan::StrictAbility
  include CanCan::Ability

  # Overrides this method: https://github.com/CanCanCommunity/cancancan/blob/2.1.2/lib/cancan/ability.rb#L67-L74
  # NOTE: on newer cancans, the implementation of that method changed to allow attribute level rules
  def can?(action, subject, *extra_args)
    had_relevant_rule = false

JoshCheek

# Library implementation of what it feels like cancan should have been
module NotCanCan
  class Permission
    attr_reader :verb, :direct_object, :default, :dynamic_override

    def initialize(verb, direct_object, default, &dynamic_override)
      @verb, @direct_object = verb, direct_object
      @default, @dynamic_override = !!default, dynamic_override
    end

JoshCheek

require 'cancan'

# Some models
Post = Struct.new(:author, :published, :body) { alias published? published }
User = Struct.new(:name, :admin) { alias admin? admin }

# Abilities
class CommonAbility
  include CanCan::Ability
  def initialize(user)

JoshCheek

# configure activerecord (in-memory sqlite db to keep it simple)
require 'active_record'
ActiveRecord::Base.establish_connection adapter: 'sqlite3', database: ':memory:'

# helper method for asserting expectations
def check!(expected, operator = :==, actual)
  equal = expected.public_send(operator, actual) and return
  raise RuntimeError, <<~MESSAGE, caller
    test:     #{expected.inspect} #{operator} #{actual.inspect}
    expected: true

JoshCheek

# Asking the twitterverse how to deal with this: https://twitter.com/josh_cheek/status/1529326801654358023

# Configure ActiveRecord
require 'active_record'
ActiveRecord::Base.establish_connection adapter: 'sqlite3', database: ':memory:'

# Migrations
ActiveRecord::Schema.define do
  self.verbose = false
  create_table :users do |t|

JoshCheek

# Was super struggling to get my array to validate (nil is bad, empty array is fine, nonempty array should contain strings)
# Finally went and read the code, and it looked totally buggy (b/c `nil` is `blank?`:
# https://github.com/rails/rails/blob/25b126707152de3a1ec9762ee564f3c7623373b3/activemodel/lib/active_model/validator.rb#L151
# Made this test to demonstrate.

require 'active_model'

def test(*values, **validation)
  [false, true].product([false, true]).map.with_index 1 do |(allow_nil, allow_blank), index|
    klass = Struct.new(:values, keyword_init: true) { include ActiveModel::Validations }

JoshCheek

# https://twitter.com/josh_cheek/status/1522312126995611651
def UnmatchedCase(...)
  UnmatchedCase.new(...)
end

class UnmatchedCase < RuntimeError
  PENDING = Struct.new(:inspect).new('(PENDING)')

  attr_reader :description, :value
  def initialize(description, value = PENDING)

JoshCheek

require 'active_record'
ActiveRecord::Base.establish_connection adapter: 'postgresql', database: 'josh_test'
ActiveRecord::Schema.define do
  self.verbose = false
  enable_extension 'pgcrypto'
  create_table :conversations, id: :uuid do |t|
    t.string :topic
  end
  create_table :messages, id: :uuid do |t|
    t.uuid :conversation_id, null: false, index: true