Cherry Pick commits from an external repository

cherry_pick_external.rb

#!/usr/bin/env ruby
require 'pry'
require 'colored'
require 'trollop'

class CherryPickExternal
  attr_accessor :external_repo, :sha, :elapsed, :color_output, :test_run

  def self.run(*args)
    start_time = Time.now
    opts = Trollop::options do
      opt(:external_repo, "Path to external repository's '.git' directory.", type: :string, short: 'r', required: true)
      opt(:sha, 'The commit SHA of the external repo', type: :string, short: 's', required: true)
      opt(:color, 'Print colored output', default: true, short: 'c')
      opt(:test_run, 'Look at the patch output but do not apply it', default: false, short: 't')
    end

    instance = CherryPickExternal.new(opts)
    instance.process
    instance.elapsed = Time.now - start_time
    instance.report_summary
  end

  def initialize(opts)
    self.external_repo = opts[:external_repo]
    self.sha           = opts[:sha]
    self.color_output  = opts[:color]
    self.test_run      = opts[:test_run]
  end

  def color(string, clr)
    if self.color_output
      string.send(clr)
    else
      string
    end
  end

  def report_summary
    puts(color(">>> Processed in [#{elapsed}] seconds", :red))
  end

  def normalized_repo_path
    self.external_repo += '.git' unless self.external_repo.match(/\.git$/)
    self.external_repo = File.expand_path(external_repo, Dir.getwd)
  end

  def process
    cmd = `which git`.chomp
    cmd << " --git-dir=#{normalized_repo_path}"
    cmd << " format-patch -k -1 --stdout"
    cmd << " #{sha} | git am -3 -k" unless self.test_run
    out = `#{cmd}`
    puts(">>> #{out}")
  end

end
CherryPickExternal.run(ARGV)