Get a markdown list of the pull requests merged into master since production's HEAD

run.rb

#!/usr/bin/env ruby

raise 'I require Ruby 2.0+!' unless RUBY_VERSION[/^2/]

def get_production_remote_name
  ENV["PRODUCTION"] || "production"
end

def extract_hashes(production_remote_name:)
  command = [
    "git log #{production_remote_name}/master..origin/master --merges --pretty=oneline",
    %Q(grep "Merge pull request"),
    "awk '{print $1}'",
  ].join(" | ")
  `#{command}`.split("\n").reverse
end

def extract_pull_request_number(hash)
  command = "git show #{hash} --pretty=full"
  message = `#{command}`
  match_data = message.match(/Merge pull request #(\d+)/)
  match_data[1]
end

def extract_merge_title(hash)
  command = "git show #{hash} --pretty=full | tail -2 | head -1"
  `#{command}`.strip
end

def extract_github_owner_and_project_name
  command = "cat .git/config | grep github"
  result = `#{command}`.strip
  match_data = result.match(/github.com:([\w-]+)\/([\w-]+)\.git/)
  match_data[1..-1]
end

def has_migrations?(hash)
  command = "git show #{hash} --format=fuller --stat=1000"
  result = `#{command}`
  result.include?("db/migrate")
end

def build_link_for(hash, github_owner, github_project_name)
  pull_request_number = extract_pull_request_number(hash)
  "https://github.com/#{github_owner}/#{github_project_name}/pull/#{pull_request_number}"
end

def build_markdown_link_for(hash, github_owner, github_project_name)
  url = build_link_for(hash, github_owner, github_project_name)
  title = extract_merge_title(hash)
  str = "[#{title}](#{url})"
  str = "#{str} (has migrations)" if has_migrations?(hash)
  str
end

def build_markdown_links_from(hashes, github_owner, github_project_name)
  hashes.map do |hash|
    build_markdown_link_for(hash, github_owner, github_project_name)
  end
end

def build_markdown_list(hashes, github_owner, github_project_name)
  links = build_markdown_links_from(hashes, github_owner, github_project_name)
  links.map do |link|
    "- #{link}"
  end.join("\n")
end

def update_remotes
  [
    "git fetch",
    "git rebase origin/master",
    "git fetch #{get_production_remote_name}",
  ].each do |update_command|
    `#{update_command}`
  end
end

update_remotes
hashes = extract_hashes(production_remote_name: get_production_remote_name)
github_owner, github_project_name = extract_github_owner_and_project_name
links = build_markdown_list(hashes, github_owner, github_project_name)

puts links