class Bundler::Dsl::DSLError

def to_s
  @to_s ||= begin
    trace_line, description = parse_line_number_from_description
    m = String.new("\n[!] ")
    m << description
    m << ". Bundler cannot continue.\n"
    return m unless backtrace && dsl_path && contents
    trace_line = backtrace.find {|l| l.include?(dsl_path.to_s) } || trace_line
    return m unless trace_line
    line_numer = trace_line.split(":")[1].to_i - 1
    return m unless line_numer
    lines      = contents.lines.to_a
    indent     = " #  "
    indicator  = indent.tr("#", ">")
    first_line = line_numer.zero?
    last_line  = (line_numer == (lines.count - 1))
    m << "\n"
    m << "#{indent}from #{trace_line.gsub(/:in.*$/, "")}\n"
    m << "#{indent}-------------------------------------------\n"
    m << "#{indent}#{lines[line_numer - 1]}" unless first_line
    m << "#{indicator}#{lines[line_numer]}"
    m << "#{indent}#{lines[line_numer + 1]}" unless last_line
    m << "\n" unless m.end_with?("\n")
    m << "#{indent}-------------------------------------------\n"
  end
end