rails - files in autoload_paths folder aren't loaded - ruby-on-rails

Question

I have a app/extensions folder where my custom exceptions reside and where I extend some of the Ruby/Rails classes. Currently there are two files: exceptions.rb and float.rb.
The folder is specified in the ActiveSupport::Dependencies.autoload_paths:
/Users/mityakoval/rails/efo/app/extensions/**
/Users/mityakoval/rails/efo/app/assets
/Users/mityakoval/rails/efo/app/channels
/Users/mityakoval/rails/efo/app/controllers
/Users/mityakoval/rails/efo/app/controllers/concerns
/Users/mityakoval/rails/efo/app/extensions
/Users/mityakoval/rails/efo/app/helpers
/Users/mityakoval/rails/efo/app/jobs
/Users/mityakoval/rails/efo/app/mailers
/Users/mityakoval/rails/efo/app/models
/Users/mityakoval/rails/efo/app/models/concerns
/Users/mityakoval/rails/efo/app/template.xlsx
/Users/mityakoval/.rvm/gems/ruby-2.4.1#web_app/gems/font-awesome-rails-4.7.0.2/app/assets
/Users/mityakoval/.rvm/gems/ruby-2.4.1#web_app/gems/font-awesome-rails-4.7.0.2/app/helpers
/Users/mityakoval/rails/efo/test/mailers/previews
The reason for it to be listed there twice is that it should be automatically loaded since it was placed under app directory and I have also manually added it to the autoload_paths in application.rb:
config.autoload_paths << File.join(Rails.root, 'app', 'extensions/**')
The strange thing is that my exceptions.rb is successfully loaded at all times, but the float.rb isn't unless eager loading is enabled.
Answers to this question say that it might be related to Spring (which I tend to believe), so I've added the folder to spring.rb:
%w(
.ruby-version
.rbenv-vars
tmp/restart.txt
tmp/caching-dev.txt
config/application.yml
app/extensions
).each { |path| Spring.watch(path) }
I've restarted Spring and the Rails server multiple times and nothing worked. Does anyone have any suggestions?
Ruby version: 2.4.1
Rails version: 5.1.5
EDIT
/Users/mityakoval/rails/efo/app/extensions/float.rb:
class Float
def comma_sep
self.to_s.gsub('.', ',')
end
end
rails console:
irb> num = 29.1
irb> num.comma_sep
NoMethodError: undefined method `comma_sep' for 29.1:Float
from (irb):2

Answer 1

A better way to monkeypatch a core class is by creating a module and including it in the class to be patched in an initializer:
# /lib/core_extensions/comma_seperated.rb
module CoreExtensions
module CommaSeperated
def comma_sep
self.to_s.gsub('.', ',')
end
end
end
# /app/initializers/core_extensions.rb
require Rails.root.join('lib', 'core_extensions', 'comma_seperated')
# or to require all files in dir:
Dir.glob(Rails.root.join('lib', 'core_extensions', '*.rb')).each do |f|
require f
end
Float.include CoreExtensions::CommaSeperated
Note that here we are not using the Rails autoloader at all and explicitly requiring the patch. Also note that we are placing the files in /lib not /app. Any files that are not application specific should be placed /lib.
Placing the monkey-patch in a module lets you test the code by including it in an arbitrary class.
class DummyFloat
include CoreExtensions::CommaSeperated
def initialize(value)
#value = value
end
def to_s
#value.to_s
end
end
RSpec.describe CoreExtensions::CommaSeperated do
subject { DummyFloat.new(1.01) }
it "produces a comma seperated string" do
expect(subject.comma_sep).to eq "1,01"
end
end
This also provides a much better stacktrace and makes it much easier to turn the monkey patch off and on.
But in this case I would argue that you don't need it in the first place - Rails has plenty of helpers to humanize and localize numbers in ActionView::Helpers::NumberHelper. NumberHelper also correctly provides helper methods instead of monkeypatching a core Ruby class which is generally best avoided.
See:
3 Ways to Monkey-Patch Without Making a Mess