Babushka shell command patched to work with rbenv and .ruby-version

shell_helpers.rb

# rbenv shell helper patch
module Babushka
  module ShellHelpers

    # Run +cmd+ via #shell, raising an exception if it doesn't exit
    # with success.
    def shell! *cmd, &block
      opts = cmd.extract_options!
      cmd = cmd.first if cmd.map(&:class) == [Array]

      if opts[:cd]
        if !opts[:cd].p.exists?
          if opts[:create]
            opts[:cd].p.mkdir
          else
            raise Errno::ENOENT, opts[:cd]
          end
        elsif !opts[:cd].p.dir?
          raise Errno::ENOTDIR, opts[:cd]
        end

        # prefix cmd with rbenv init if ./ruby-version exists in path
        cmd[0] = "#{rbenv_prefix(opts[:cd])} #{cmd[0]}"
      end

      shell_method = (opts[:as] || opts[:sudo]) ? :sudo : :shell_cmd
      send shell_method, *cmd.dup.push(opts), &block
    end


    private

    def rbenv_version_file(path)
      "#{path}/.ruby-version".p
    end

    def rbenv_prefix(path)
      if rbenv_version_file(path).exists?
        "eval \"$(rbenv init -)\" && RBENV_VERSION=#{rbenv_version_file(path).read}"
      end
    end
  end
end

Reads a .ruby-version file from working shell cmd directory (if it exists), and prepends the shell command with;

eval "$(rbenv init -)" && RBENV_VERSION=2.1.2

When running the shell will be properly setup to use the ruby (or gems) that have been installed with rbenv. This can be required in deps with something like;

require_relative 'lib/babushka_ext/shell_helpers'