pboling/version_gem

#!/usr/bin/env ruby
# frozen_string_literal: true

#
# This file was generated by Bundler.
#
# The application 'bundle' is installed as part of a gem, and
# this file is here to facilitate running it.
#

require 'rubygems'

m = Module.new do
  module_function

  def invoked_as_script?
    File.expand_path($PROGRAM_NAME) == File.expand_path(__FILE__)
  end

  def env_var_version
    ENV.fetch('BUNDLER_VERSION', nil)
  end

  def cli_arg_version
    return unless invoked_as_script? # don't want to hijack other binstubs
    return unless 'update'.start_with?(ARGV.first || ' ') # must be running `bundle update`

    bundler_version = nil
    update_index = nil
    ARGV.each_with_index do |a, i|
      bundler_version = a if update_index && update_index.succ == i && a =~ Gem::Version::ANCHORED_VERSION_PATTERN
      next unless a =~ /\A--bundler(?:[= ](#{Gem::Version::VERSION_PATTERN}))?\z/

      bundler_version = Regexp.last_match(1)
      update_index = i
    end
    bundler_version
  end

  def gemfile
    gemfile = ENV.fetch('BUNDLE_GEMFILE', nil)
    return gemfile if gemfile && !gemfile.empty?

    File.expand_path('../Gemfile', __dir__)
  end

  def lockfile
    lockfile =
      case File.basename(gemfile)
      when 'gems.rb' then gemfile.sub(/\.rb$/, gemfile)
      else "#{gemfile}.lock"
      end
    File.expand_path(lockfile)
  end

  def lockfile_version
    return unless File.file?(lockfile)

    lockfile_contents = File.read(lockfile)
    return unless lockfile_contents =~ /\n\nBUNDLED WITH\n\s{2,}(#{Gem::Version::VERSION_PATTERN})\n/

    Regexp.last_match(1)
  end

  def bundler_requirement
    @bundler_requirement ||=
      env_var_version || cli_arg_version ||
      bundler_requirement_for(lockfile_version)
  end

  def bundler_requirement_for(version)
    return "#{Gem::Requirement.default}.a" unless version

    bundler_version_gemsion = Gem::Version.new(version)

    requirement = bundler_version_gemsion.approximate_recommendation

    return requirement unless Gem.rubygems_version < Gem::Version.new('2.7.0')

    requirement += '.a' if bundler_version_gemsion.prerelease?

    requirement
  end

  def load_bundler!
    ENV['BUNDLE_GEMFILE'] ||= gemfile

    activate_bundler
  end

  def activate_bundler
    gem_error = activation_error_handling do
      gem 'bundler', bundler_requirement
    end
    return if gem_error.nil?

    require_error = activation_error_handling do
      require 'bundler/version'
    end
    return if require_error.nil? && Gem::Requirement.new(bundler_requirement).satisfied_by?(Gem::Version.new(Bundler::VERSION))

    warn "Activating bundler (#{bundler_requirement}) failed:\n#{gem_error.message}\n\nTo install the version of bundler this project requires, run `gem install bundler -v '#{bundler_requirement}'`"
    exit 42
  end

  def activation_error_handling
    yield
    nil
  rescue StandardError, LoadError => e
    e
  end
end

m.load_bundler!

load Gem.bin_path('bundler', 'bundle') if m.invoked_as_script?