ruby/rubygems · error · Bundler::GemfileError

Please define :engine

Error message

Please define :engine

What it means

Error "Please define :engine" thrown in ruby/rubygems.

Source

Thrown at lib/bundler/ruby_dsl.rb:15

# frozen_string_literal: true

module Bundler
  module RubyDsl
    def ruby(*ruby_version)
      options = ruby_version.pop if ruby_version.last.is_a?(Hash)
      ruby_version.flatten!

      if options
        patchlevel = options[:patchlevel]
        engine = options[:engine]
        engine_version = options[:engine_version]

        raise GemfileError, "Please define :engine_version" if engine && engine_version.nil?
        raise GemfileError, "Please define :engine" if engine_version && engine.nil?

        if options[:file]
          raise GemfileError, "Do not pass version argument when using :file option" unless ruby_version.empty?
          ruby_version << normalize_ruby_file(options[:file])
        end

        if engine == "ruby" && engine_version && ruby_version != Array(engine_version)
          raise GemfileEvalError, "ruby_version must match the :engine_version for MRI"
        end
      end

      @ruby_version = RubyVersion.new(ruby_version, patchlevel, engine, engine_version)
    end

    # Support the various file formats found in .ruby-version files.
    #
    #     3.2.2
    #     ruby-3.2.2

View on GitHub (pinned to 86cbb817a3)

When it happens

Trigger: Thrown at lib/bundler/ruby_dsl.rb:15 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of ruby/rubygems@86cbb817a3 (2026-08-23). Data as JSON: /api/errors/6d03ec45e3e8f83f. Report an issue: GitHub.