Bundler: Bump 1 gem and touch nothing else with bundle-unlock

bundle-unlock.rb

#!/usr/bin/env ruby
#
# Updating a gem normally leads to it's dependencies being updates as well.
# This script only removes the gem itself from the lockfile, allowing to update it without
# touching anything else.
#
# bundle-unlock foobar && bundle

# Source: https://github.com/grosser/dotfiles/blob/master/bin/bundle-unlock

raise 'Give me the gems' if ARGV.empty?
lockfile = (ENV['BUNDLE_GEMFILE'] || 'Gemfile') << '.lock'
content = File.read(lockfile)

ARGV.each do |gem|
  content.sub!(/^    #{Regexp.escape(gem)} .*\n(      \S.*\n)*/, '') || raise("missing 4-space indent for #{gem}")
  content.sub!(/^  #{Regexp.escape(gem)}(\n| .*\n)(    \S.*\n)*/, '') || raise("missing 2-space indent for #{gem}")
end

File.write(lockfile, content)