brew/Library/brew.rb

#!/System/Library/Frameworks/Ruby.framework/Versions/Current/usr/bin/ruby -W0

std_trap = trap("INT") { exit! 130 } # no backtrace thanks

HOMEBREW_BREW_FILE = ENV["HOMEBREW_BREW_FILE"]

if ARGV == %w[--prefix]
  puts File.dirname(File.dirname(HOMEBREW_BREW_FILE))
  exit 0
end

require "pathname"
HOMEBREW_LIBRARY_PATH = Pathname.new(__FILE__).realpath.parent.join("Homebrew")
$:.unshift(HOMEBREW_LIBRARY_PATH.to_s)
require "global"

if ARGV == %w[--version] || ARGV == %w[-v]
  puts "Homebrew #{Homebrew.homebrew_version_string}"
  exit 0
elsif ARGV.first == "-v"
  # Shift the -v to the end of the parameter list
  ARGV << ARGV.shift
end

if OS.mac?
  # Check for bad xcode-select before other checks, because `doctor` and
  # many other things will hang. Note that this bug was fixed in 10.9
  if MacOS.version < :mavericks && MacOS.active_developer_dir == "/"
    odie <<-EOS.undent
      Your xcode-select path is currently set to '/'.
      This causes the `xcrun` tool to hang, and can render Homebrew unusable.
      If you are using Xcode, you should:
        sudo xcode-select -switch /Applications/Xcode.app
      Otherwise, you should:
        sudo rm -rf /usr/share/xcode-select
    EOS
  end

  # Check for user agreement of the Xcode license before permitting
  # any other brew usage to continue. This prevents the situation where
  # people are instructed to "please re-run as root via sudo" on brew commands.
  # The check can only fail when Xcode is installed & the active developer dir.
  if MacOS::Xcode.installed? && `/usr/bin/xcrun clang 2>&1` =~ /license/ && !$?.success?
    odie <<-EOS.undent
      You have not agreed to the Xcode license. Please resolve this by running:
        sudo xcodebuild -license
    EOS
  end
end

case HOMEBREW_PREFIX.to_s
when "/", "/usr"
  # it may work, but I only see pain this route and don't want to support it
  abort "Cowardly refusing to continue at this prefix: #{HOMEBREW_PREFIX}"
end

if OS.mac? && MacOS.version < "10.6"
  abort <<-EOABORT.undent
    Homebrew requires Snow Leopard or higher. For Tiger and Leopard support, see:
    https://github.com/mistydemeo/tigerbrew
  EOABORT
end

# Many Pathname operations use getwd when they shouldn't, and then throw
# odd exceptions. Reduce our support burden by showing a user-friendly error.
Dir.getwd rescue abort "The current working directory doesn't exist, cannot proceed."

def require?(path)
  require path
rescue LoadError => e
  # HACK: ( because we should raise on syntax errors but
  # not if the file doesn't exist. TODO make robust!
  raise unless e.to_s.include? path
end

begin
  trap("INT", std_trap) # restore default CTRL-C handler

  empty_argv = ARGV.empty?
  help_regex = /(-h$|--help$|--usage$|-\?$|^help$)/
  help_flag = false
  internal_cmd = true
  cmd = nil

  ARGV.dup.each_with_index do |arg, i|
    if help_flag && cmd
      break
    elsif arg =~ help_regex
      help_flag = true
    elsif !cmd
      cmd = ARGV.delete_at(i)
    end
  end

  cmd = HOMEBREW_INTERNAL_COMMAND_ALIASES.fetch(cmd, cmd)

  sudo_check = %w[ install reinstall postinstall link pin unpin
                   update upgrade create migrate tap switch ]

  if sudo_check.include? cmd
    if Process.uid.zero? && !File.stat(HOMEBREW_BREW_FILE).uid.zero?
      raise <<-EOS.undent
        Cowardly refusing to `sudo brew #{cmd}`
        You can use brew with sudo, but only if the brew executable is owned by root.
        However, this is both not recommended and completely unsupported so do so at
        your own risk.
      EOS
    end
  end

  # Add contributed commands to PATH before checking.
  Dir["#{HOMEBREW_LIBRARY}/Taps/*/*/cmd"].each do |tap_cmd_dir|
    ENV["PATH"] += "#{File::PATH_SEPARATOR}#{tap_cmd_dir}"
  end

  # Add SCM wrappers.
  ENV["PATH"] += "#{File::PATH_SEPARATOR}#{HOMEBREW_LIBRARY}/ENV/scm"

  if cmd
    internal_cmd = require? HOMEBREW_LIBRARY_PATH.join("cmd", cmd)

    if !internal_cmd && ARGV.homebrew_developer?
      internal_cmd = require? HOMEBREW_LIBRARY_PATH.join("dev-cmd", cmd)
    end
  end

  # Usage instructions should be displayed if and only if one of:
  # - a help flag is passed AND an internal command is matched
  # - a help flag is passed AND there is no command specified
  # - no arguments are passed
  #
  # It should never affect external commands so they can handle usage
  # arguments themselves.

  if empty_argv || (help_flag && (cmd.nil? || internal_cmd))
    # TODO: - `brew help cmd` should display subcommand help
    require "cmd/help"
    puts ARGV.usage
    exit ARGV.any? ? 0 : 1
  end

  if internal_cmd
    Homebrew.send cmd.to_s.gsub("-", "_").downcase
  elsif which "brew-#{cmd}"
    %w[CACHE CELLAR LIBRARY_PATH PREFIX REPOSITORY].each do |e|
      ENV["HOMEBREW_#{e}"] = Object.const_get("HOMEBREW_#{e}").to_s
    end
    exec "brew-#{cmd}", *ARGV
  elsif (path = which("brew-#{cmd}.rb")) && require?(path)
    exit Homebrew.failed? ? 1 : 0
  else
    require "tap"
    possible_tap = case cmd
    when *%w[brewdle brewdler bundle bundler]
      Tap.fetch("Homebrew", "bundle")
    when "cask"
      Tap.fetch("caskroom", "cask")
    when "services"
      Tap.fetch("Homebrew", "services")
    end

    if possible_tap && !possible_tap.installed?
      possible_tap.install
      exec HOMEBREW_BREW_FILE, cmd, *ARGV
    else
      onoe "Unknown command: #{cmd}"
      exit 1
    end
  end

rescue FormulaUnspecifiedError
  abort "This command requires a formula argument"
rescue KegUnspecifiedError
  abort "This command requires a keg argument"
rescue UsageError
  onoe "Invalid usage"
  abort ARGV.usage
rescue SystemExit => e
  onoe "Kernel.exit" if ARGV.verbose? && !e.success?
  puts e.backtrace if ARGV.debug?
  raise
rescue Interrupt => e
  puts # seemingly a newline is typical
  exit 130
rescue BuildError => e
  e.dump
  exit 1
rescue RuntimeError, SystemCallError => e
  raise if e.message.empty?
  onoe e
  puts e.backtrace if ARGV.debug?
  exit 1
rescue Exception => e
  onoe e
  if internal_cmd
    puts "#{Tty.white}Please report this bug:"
    puts "    #{Tty.em}#{OS::ISSUES_URL}#{Tty.reset}"
  end
  puts e.backtrace
  exit 1
else
  exit 1 if Homebrew.failed?
end