Markdown release notes since last bump commit with github links

relnotes.rb

#!/usr/bin/env ruby
#
# relnotes.rb
# Markdown release notes since last bump commit with github links
# Awesome for creating release notes for a release.
#
# Usage: ruby relnotes.rb [github-prefix]
#
# The script will extract all git commits since the last "bump commit" (a commit with the text "bump") 
# and will generate a bulletted description of all the commits. If `github-prefix` is provided (e.g. "eladb/myrepo"),
# the script will replace "#nnn" and commit hashes with their github links.
#

def replace_github_issues(text, github_repo)
  pos = 0
  while true
    m = text.match(/(#\d+)/, pos)
    return text unless m

    offset = m.offset(0)
    before = text.slice(0, offset[0])
    after = text.slice(offset[1], 99)
    text = "#{before}[#{m[0]}](http://github.com/#{github_repo}/issues/#{m[0][1..-1]})#{after}"
    pos = offset[1]
  end
end

github_repo = ARGV[0]
last_bump = `git --no-pager log --grep bump -i -n1 --pretty=format:%H`
commits = `git --no-pager log --pretty=format:'%h\t%s\t%an\t' #{last_bump}..HEAD`.split("\n").map do |line|
  hash, subject, author = line.split("\t")

  # if subject contains an issue number, convert it into a link
  # subject.to_enum(:scan, /(#\d+)/).map { Regexp.last_match }.each do |m|
  subject = replace_github_issues(subject, github_repo) if github_repo

  {
    :hash => hash,
    :subject => subject,
    :author => author,
    :commit_link => github_repo && "https://github.com/#{github_repo}/commit/#{hash}",
  }
end

commits.each do |commit|
  if commit[:commit_link]
    puts " - [#{commit[:hash]}](#{commit[:commit_link]}): #{commit[:subject].capitalize} (_#{commit[:author]}_)"
  else
    puts " - #{commit[:hash]}: #{commit[:subject].capitalize} (_#{commit[:author]}_)"
  end    
end