tracks/vendor/rails/railties/lib/tasks/framework.rake

namespace :rails do
  namespace :freeze do
    desc "Lock this application to the current gems (by unpacking them into vendor/rails)"
    task :gems do
      deps = %w(actionpack activerecord actionmailer activesupport activeresource)
      require 'rubygems'
      require 'rubygems/gem_runner'
      Gem.manage_gems

      rails = (version = ENV['VERSION']) ?
        Gem.cache.find_name('rails', "= #{version}").first :
        Gem.cache.find_name('rails').sort_by { |g| g.version }.last

      version ||= rails.version

      unless rails
        puts "No rails gem #{version} is installed.  Do 'gem list rails' to see what you have available."
        exit
      end

      puts "Freezing to the gems for Rails #{rails.version}"
      rm_rf   "vendor/rails"
      mkdir_p "vendor/rails"

      begin
        chdir("vendor/rails") do
          rails.dependencies.select { |g| deps.include? g.name }.each do |g|
            Gem::GemRunner.new.run(["unpack", g.name, "--version", g.version_requirements.to_s])
            mv(Dir.glob("#{g.name}*").first, g.name)
          end

          Gem::GemRunner.new.run(["unpack", "rails", "--version", "=#{version}"])
          FileUtils.mv(Dir.glob("rails*").first, "railties")
        end
      rescue Exception
        rm_rf "vendor/rails"
        raise
      end
    end

    desc 'Lock to latest Edge Rails, for a specific release use RELEASE=1.2.0'
    task :edge do
      require 'open-uri'
      version = ENV["RELEASE"] || "edge"
      target  = "rails_#{version}.zip"
      url     = "http://dev.rubyonrails.org/archives/#{target}"

      chdir 'vendor' do
        puts "Downloading Rails from #{url}"
        File.open('rails.zip', 'wb') do |dst|
          open url do |src|
            while chunk = src.read(4096)
              dst << chunk
            end
          end
        end

        puts 'Unpacking Rails'
        rm_rf 'rails'
        `unzip rails.zip`
        %w(rails.zip rails/Rakefile rails/cleanlogs.sh rails/pushgems.rb rails/release.rb).each do |goner|
          rm_f goner
        end
      end

      puts 'Updating current scripts, javascripts, and configuration settings'
      Rake::Task['rails:update'].invoke
    end
  end

  desc "Unlock this application from freeze of gems or edge and return to a fluid use of system gems"
  task :unfreeze do
    rm_rf "vendor/rails"
  end

  desc "Update both configs, scripts and public/javascripts from Rails"
  task :update => [ "update:scripts", "update:javascripts", "update:configs" ]

  namespace :update do
    desc "Add new scripts to the application script/ directory"
    task :scripts do
      local_base = "script"
      edge_base  = "#{File.dirname(__FILE__)}/../../bin"

      local = Dir["#{local_base}/**/*"].reject { |path| File.directory?(path) }
      edge  = Dir["#{edge_base}/**/*"].reject { |path| File.directory?(path) }
  
      edge.each do |script|
        base_name = script[(edge_base.length+1)..-1]
        next if base_name == "rails"
        next if local.detect { |path| base_name == path[(local_base.length+1)..-1] }
        if !File.directory?("#{local_base}/#{File.dirname(base_name)}")
          mkdir_p "#{local_base}/#{File.dirname(base_name)}"
        end
        install script, "#{local_base}/#{base_name}", :mode => 0755
      end
    end

    desc "Update your javascripts from your current rails install"
    task :javascripts do
      require 'railties_path'  
      project_dir = RAILS_ROOT + '/public/javascripts/'
      scripts = Dir[RAILTIES_PATH + '/html/javascripts/*.js']
      scripts.reject!{|s| File.basename(s) == 'application.js'} if File.exist?(project_dir + 'application.js')
      FileUtils.cp(scripts, project_dir)
    end

    desc "Update config/boot.rb from your current rails install"
    task :configs do
      require 'railties_path'  
      FileUtils.cp(RAILTIES_PATH + '/environments/boot.rb', RAILS_ROOT + '/config/boot.rb')
    end
  end
end