A better Rakefile for rails?

explanation.md

If you have rake tasks that don't rely on rails, it's really annoying that rails has to load before the tasks runs.

Instead this rakefile only loads rails if a rake task which depends on :environment is called.

One caveat is that rake -T won't list rails/gem tasks, hence the added warning. To show all tasks use rake -T LOAD_RAILS=1

With thanks to @xshay http://rhnh.net/2010/09/07/speeding-up-rails-rake

Any thoughts?

Rakefile

#!/usr/bin/env rake
# Add your own tasks in files placed in lib/tasks ending in .rake,
# for example lib/tasks/capistrano.rake, and they will automatically be available to Rake.

#Load all the tasks in lib/tasks
Dir[File.expand_path('../lib/tasks/', __FILE__) + '/*.rake'].each do |file|
  load file
end

#The original rails rakefile loading
def load_rails_environment
  require File.expand_path('../config/application', __FILE__)
  require 'rake'
  MyApp::Application.load_tasks
end


#Catch task missing and try again
class Rake::Application
  private
  alias_method :invoke_task_without_catch, :invoke_task

  def invoke_task_with_catch(*args)
    begin
      invoke_task_without_catch(*args)
    rescue RuntimeError => e
      begin
        load_rails_environment
        invoke_task_without_catch(*args)
      rescue Exception => e
        raise(e)
      end
    end
  end
  alias_method :invoke_task, :invoke_task_with_catch
end



#Add a task to the top of the rake -T list, to explain how to get the full list
#of tasks including rails and gem tasks
if ENV['LOAD_RAILS'] == '1'
  load_rails_environment
else
  desc "!!! Rails and gem tasks are not listed, rerun with LOAD_RAILS=1 to reveal"
  task :_README
end

I like this. I personally have a separate rspec suite for most of my application logic that exists outside of rails -- this is the best implementation of fighting Rails worming its way into your Rakefile that I've seen yet.

What's the point of doing this inside of the first rescue:

begin
  load_rails_environment
  invoke_task_without_catch(*args)
rescue Exception => e
  raise(e)
end

Why not just:

load_rails_environment
invoke_task_without_catch(*args)

There appears to be a problem with this. If a task throws an error, rake seems to mark it as failed and won't run it again, so the invoke_.. in the rescue doesn't actually invoke the task. Still working on a solution, probably something involving reenable.