Ruby 2.4 module name conflict with my model class name

Question

I'm upgrading Ruby's version from 2.3.8 to 2.4.4 on Rails 5.2.3.

When I start the application I get this error:

app/models/warning.rb:1:in `<main>': Warning is not a class (TypeError)

when called on console: Warning.class => Module

But in fact it is one of my models called Warning.

I saw in released notes an introduction to a new module on ruby 2.4 called Warning. but how can I avoid this conflict without renaming my model with migrations?

score 3 · Accepted Answer · answered Mar 05 '20 at 15:20

Warning module is used for overriding ruby warn method. To temporarily get around the error - you can undefine the constant before defining your model:

Object.send(:remove_const, :Warning)

runnable test:

require "bundler/inline"
gemfile(true) do
  source "https://rubygems.org"
  gem "activerecord", "5.2.3"
  gem "sqlite3", "~> 1.3.6"
end

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

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Schema.define do
  create_table(:warnings, force: true){|t| t.string  :name }
end

RubyWarning = Warning
Object.send(:remove_const, :Warning)

class Warning < ActiveRecord::Base
end

def RubyWarning.warn(str)
  puts "still works: #{str}"
end

class SomeTest < Minitest::Test
  def test_stuff
    wrn = Warning.create name: 'test'
    assert_equal(wrn.name, 'test')
    warn "Test warn"
  end
end

Ruby 2.4 module name conflict with my model class name

1 Answers1