Get transitive gem dependencies

gem-dependencies.rb

#!/usr/bin/env ruby
require 'set'

def get_gem_dependencies(gem_name, version = nil)
  require 'open-uri'
  require 'yaml'

  url = if version
    "https://rubygems.org/api/v2/rubygems/#{gem_name}/versions/#{version}.yaml"
  else
    "https://rubygems.org/api/v1/gems/#{gem_name}.yaml"
  end

  begin
    yaml_content = URI.open(url).read
    gem_info = YAML.safe_load(yaml_content)

    gem_info['dependencies']['runtime'] || []
  rescue OpenURI::HTTPError => e
    puts "Error fetching gem info: #{e.message}"
    []
  end
end

def get_transitive_dependencies(gem_name, version = nil, visited = Set.new)
  return [] if visited.include?(gem_name)

  visited.add(gem_name)

  dependencies = get_gem_dependencies(gem_name, version)

  transitive_deps = dependencies.flat_map do |dep|
    dep_name = dep["name"]
    [dep] + get_transitive_dependencies(dep_name, nil, visited)
  end

  transitive_deps.uniq
end

if ARGV.empty?
  puts "Usage: #{$PROGRAM_NAME} GEM_NAME [VERSION]"
  exit 1
end

gem_name = ARGV[0]
version = ARGV[1]

begin
  dependencies = get_transitive_dependencies(gem_name, version)
  puts "Transitive dependencies for #{gem_name}#{version ? " (#{version})" : ""}:"
  dependencies.each { |dep| puts "- #{dep['name']} (#{dep['requirements']}) " }
rescue => e
  puts "Error: #{e.message}"
  exit 1
end