utility script to find which gems are dependent on a given gem provided a filter.

find-dependent-gems

#!/usr/bin/env ruby

require 'optparse'
require 'shellwords'

options = {}
OptionParser.new do |opts|
  opts.banner = "Usage: #{__FILE__} [options]"

  opts.on("-g", "--gem=GEM") do |gem|
    options[:gem] = gem
  end

  opts.on("-f", "--filter=FILTER") do |filter|
    options[:filter] = Regexp.new(filter)
  end

  opts.on("-h", "--help", "Print this message") do
    puts opts
    exit
  end
end.parse!

fail "Must provide a gem name. See --help for more info." unless options[:gem]
fail "Must provide a gem filter. See --help for more info." unless options[:filter]

puts "Searching for gems that match the filter #{options[:filter]} for a dependency on #{options[:gem]}"
puts

command = <<~SHELL
  gem search -r "#{options[:filter]}" | cut -f1 -d" "
SHELL

output = `#{command}`
gems = output.split(/\n/)
dependent_gems = gems.select do |gem|
  printf "%-40s", gem
  if `gem dependency -r #{gem}` =~ /#{Regexp.new(options[:gem])}/m
    puts "\e[32mdepends\e[0m"
    true
  else
    puts "no dependency"
  end
end

puts
puts "Done. #{dependent_gems.length} depend on #{options[:gem]} matching filter #{options[:filter]}"