Command to delete old remote branches

git-prune-remote-branches

#!/usr/bin/env ruby

require 'time'

class App
  CUTOFF_DAYS = 30

  def initialize(args)
    args.size <= 1 or
      abort "USAGE: #$0 [remote]"
    @remote = args.first || 'origin'
  end

  def run
    branches = stagnant_branches
    if confirm(branches)
      delete_branches(branches)
    else
      abort 'Aborted.'
    end
  end

  private

  def stagnant_branches
    cutoff = Time.now - CUTOFF_DAYS*24*60*60
    all_branches.select { |b| b.last_updated_at.nil? || b.last_updated_at < cutoff }
  end

  def all_branches
    `git branch --no-color -r`.lines.map do |line|
      line =~ /\A..#@remote\/(\S+)/ or
        next
      Branch.new(@remote, $1)
    end.compact.sort_by { |b| b.last_updated_at || Time.at(0) }.reverse
  end

  def confirm(branches)
    branches.each do |branch|
      puts "  #{branch.info}"
    end
    $>.sync = true
    loop do
      $>.print "Delete these branches? [y/n] "
      case $<.gets.strip
      when /\Ay(?:es)?\z/i
        return true
      when /\Ano?\z/i
        return false
      end
    end
  end

  def delete_branches(branches)
    puts "Deleting:"
    branches.each do |branch|
      puts "  #{branch.name}: #{branch.sha}"
    end
    refspecs = branches.map { |b| ":#{b.name}" }
    #sh "git push #@remote #{refspecs.join(' ')}"
  end

  def sh(command)
    puts "++ #{command}"
    system command
  end

  class Branch
    def initialize(remote, name)
      @remote = remote
      @name = name
    end

    attr_reader :remote, :name

    def last_updated_at
      @last_updated_at ||= find_last_reflog_date || find_last_commit_date
    end

    def info
      if num_commits > 0
        "#{name} - #{age}, #{num_commits} commits by #{authors.join(', ')}"
      else
        "#{name} - #{age}, no commits"
      end
    end

    def sha
      `git log -n 1 --format=%H #@remote/#@name`.chomp
    end

    private

    def age
      if last_updated_at
        seconds_ago = Time.now - last_updated_at
        days_ago = (seconds_ago / 24 / 60 / 60).round
        "#{days_ago} days old"
      else
        "age unknown"
      end
    end

    def num_commits
      @num_commits ||= commits.size
    end

    def authors
      @authors ||= commits.map { |sha, author| author.split(/&/).map(&:strip) }.flatten.uniq.sort
    end

    def commits
      @commits ||= `git log --format=%H:%an #@remote/master..#@remote/#@name`.lines.map do |line|
        line.chomp.split(/:/)
      end
    end

    def find_last_reflog_date
      output = `git log -g -n 1 --date=local --pretty=%gd #@remote/#@name`
      time_string = output[/(?<=@\{)(.*)(?>\})/] or
        return nil
      DateTime.parse(time_string).to_time
    end

    def find_last_commit_date
      output = `git log -n 1 --format=%cd #@remote/#@name`.chomp
      DateTime.parse(output).to_time
    end
  end
end

App.new(ARGV).run