class Bundler::SelfManager

def restart_with(version)
  configured_gem_home = ENV["GEM_HOME"]
  configured_gem_path = ENV["GEM_PATH"]
  # Bundler specs need some stuff to be required before Bundler starts
  # running, for example, for faking the compact index API. However, these
  # flags are lost when we reexec to a different version of Bundler. In the
  # future, we may be able to properly reconstruct the original Ruby
  # invocation (see https://bugs.ruby-lang.org/issues/6648), but for now
  # there's no way to do it, so we need to be explicit about how to re-exec.
  # This may be a feature end users request at some point, but maybe by that
  # time, we have builtin tools to do. So for now, we use an undocumented
  # ENV variable only for our specs.
  bundler_spec_original_cmd = ENV["BUNDLER_SPEC_ORIGINAL_CMD"]
  if bundler_spec_original_cmd
    require "shellwords"
    cmd = [*Shellwords.shellsplit(bundler_spec_original_cmd), *ARGV]
  else
    argv0 = File.exist?($PROGRAM_NAME) ? $PROGRAM_NAME : Process.argv0
    cmd = [argv0, *ARGV]
    cmd.unshift(Gem.ruby) unless File.executable?(argv0)
  end
  Bundler.with_original_env do
    Kernel.exec(
      { "GEM_HOME" => configured_gem_home, "GEM_PATH" => configured_gem_path, "BUNDLER_VERSION" => version.to_s },
      *cmd
    )
  end
end