ruby script that makes merging up and pushing changes easy for versions ahead (if you follow semantic versioning)

git_merge_up_push_up_version.rb

#!/usr/bin/env ruby
require 'rubygems'
require 'set'
require 'highline/import'

# this assumes you follow proper semantic app versioning
# listen to this http://fragmentedpodcast.com/episodes/054/ for an explanation

def confirm(message)
  confirmation = ask message + " (y/n)"
  if confirmation != "y"
    puts "Grr... exiting"
    exit
  end
end

def current_branch
  current_branch = `git branch --no-color | grep '*'`.split.last
end

def upper_branch(last_3_releases, current_branch)
  upper_branch = ""
  return "" if current_branch == "master"
  last_3_releases.each do |release|
      upper_branch = release if release > current_branch
      break if !upper_branch.empty?
  end
  if upper_branch.empty?
      "master"
  else
     upper_branch
  end
end

def last_3_releases
  last_3_releases = SortedSet.new
  all_branches = `git branch -a --no-color`
  all_branches.split("\n").each do |branch_name|
    branch_name = branch_name.strip
    next if !branch_name.start_with? "remotes/origin/release/"
    branch_name["remotes/origin/"] = ""
    last_3_releases << branch_name
    last_3_releases.delete(last_3_releases.first) if last_3_releases.size > 3
  end
  last_3_releases
end

def exit_if_merge_conflict
  conflicting_files = `git ls-files -u`
  return if conflicting_files.empty?
  puts "merge conflict detected. Sorry you're on your own!\n#{conflicting_files}\n\nEXITING\n"
  exit
end


def merge_up(current_branch)

  puts "\n\n\n--- pulling latest changes for this branch"
  system("git pull --no-ff")

  exit_if_merge_conflict()

  confirm "git pushing #{current_branch}"
  system("git push")

  return "" if current_branch == "master"

  puts "\n\n--- current branch is #{current_branch}"
  prev_branch = current_branch
  next_branch = upper_branch(last_3_releases, prev_branch)

  confirm "--- moving from #{prev_branch} -> #{next_branch}\nlooks good?"
  system("git checkout #{next_branch}")


  puts "\n\n\n--- pulling latest changes for this branch"
  system("git pull --no-ff")

  exit_if_merge_conflict()

  confirm "merging branch #{prev_branch} onto #{next_branch}"
  system("git merge --no-ff #{prev_branch}")

  exit_if_merge_conflict()

  confirm "git pushing #{next_branch}"
  system("git push")

  next_branch
end


def main
  puts "--- fetching all latest branches from server"
  system("git fetch origin")


  last_3_releases = last_3_releases()

  next_branch = current_branch()
  while !next_branch.empty?
    next_branch = merge_up(next_branch)
    break if next_branch == "master"
  end
end
main()