ruby/rubygems · error · InvalidOption

Extensions can now be generated using C or Rust, so `--ext`

Error message

Extensions can now be generated using C or Rust, so `--ext` with no arguments has been removed. Please select a language, e.g. `--ext=rust` to generate a Rust extension.

What it means

Error "Extensions can now be generated using C or Rust, so `--ext` with no arguments has been removed. Please select a language, e.g. `--ext=rust` to generate a Rust extension." thrown in ruby/rubygems.

Source

Thrown at lib/bundler/cli.rb:719

        if exec_used + help_used == 1
          %w[help exec]
        else
          args
        end
      elsif help_used
        args = args.dup
        args.delete_at(help_used)
        ["help", command || args].flatten.compact
      else
        args
      end
    end

    def self.check_invalid_ext_option(arguments)
      # when invalid version of `--ext` is called
      if invalid_ext_value?(arguments)
        removed_message = "Extensions can now be generated using C or Rust, so `--ext` with no arguments has been removed. Please select a language, e.g. `--ext=rust` to generate a Rust extension."
        raise InvalidOption, removed_message
      end
    end

    def self.invalid_ext_value?(arguments)
      index = arguments.index("--ext")
      next_argument = arguments[index + 1]

      # it is ok when --ext is followed with valid extension value
      # for example `bundle gem hello --ext c`
      return false if EXTENSIONS.include?(next_argument)

      # invalid call when --ext is called with no value in last position
      # for example `bundle gem hello_gem --ext`
      return true if next_argument.nil?

      # invalid call when --ext is followed by other parameter
      # for example `bundle gem --ext --no-ci hello_gem`
      return true if next_argument.start_with?("-")

View on GitHub (pinned to 86cbb817a3)

When it happens

Trigger: Thrown at lib/bundler/cli.rb:719 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/907eef974484264f. Report an issue: GitHub.