git-chain-rebase

git-chain-rebase

#! /usr/bin/env ruby
# frozen_string_literal: true

raise 'requires at least the new base and 1 branch to rebase' if ARGV.length < 2

to_rebase = ARGV[0]
new_base = ARGV[1]

puts "to rebase: #{to_rebase.inspect}"
puts "new base: #{new_base.inspect}"

merge_base = `git merge-base #{to_rebase} #{new_base}`.strip

onto = ARGV[2] || merge_base

puts
puts "onto: #{onto.inspect}"

branches = `git log --abbrev-commit --decorate --format=format:'%d' #{onto}..#{to_rebase}`
  .gsub(/[()]/, '')
  .split(/\n|,/)
  .reject { |l| l =~ %r{/} || l =~ /\A\s*\Z/ }
  .map { |l| l.gsub(/HEAD *-> */, '') }
  .reverse

puts
puts "branches: #{branches.join(' => ')}"

rebases = ([nil] + branches)
  .each_cons(2)
  .map do |previous, current|
    next "git checkout #{current} && git rebase --onto #{new_base} #{onto}" unless previous

    "git checkout #{current} && git rebase --onto #{previous} #{`git rev-parse #{previous}`.strip}"
  end
  .join ' && '

puts
puts rebases.gsub(/&& /, "&& \\\n  ")
puts 'Ready to proceed? Y/n'
ready = STDIN.gets.chomp
exit 0 unless ready =~ /\Ay(?:es)?\Z/i
system(rebases)

push = "git push --force-with-lease origin #{branches.join(' ')}"
puts
puts push
puts 'Ready to proceed? Y/n'
ready = STDIN.gets.chomp
exit 0 unless ready =~ /\Ay(?:es)?\Z/i
system(push)

puts
puts 'All done :)'