--force option in invalid option while rails g controller <glass> --force

Not sure if it is a bug or I am missing something.

I am getting following error with rails edge.

(master)$ rails g controller glass --force
   identical  app/controllers/glass_controller.rb
      invoke  erb
       exist    app/views/glass
      invoke  test_unit
   identical    test/functional/glass_controller_test.rb
      invoke  helper
   identical    app/helpers/glass_helper.rb
      invoke    test_unit
   identical      test/unit/helpers/glass_helper_test.rb
invalid option: --force
Test::Unit automatic runner.
Usage: script/rails [options] [-- untouched arguments]

    -r, --runner=RUNNER              Use the given RUNNER.
                                     (c[onsole], f[ox], g[tk], g[tk]2, t[k])
    -n, --name=NAME                  Runs tests matching NAME.
                                     (patterns may be used).
    -t, --testcase=TESTCASE          Runs tests in TestCases matching TESTCASE.
                                     (patterns may be used).
    -I, --load-path=DIR[:DIR...]     Appends directory list to $LOAD_PATH.
    -v, --verbose=[LEVEL]            Set the output level (default is verbose).
                                     (s[ilent], p[rogress], n[ormal], v[erbose])
        --                           Stop processing options so that the
                                     remaining options will be passed to the
                                     test.
    -h, --help                       Display this help.

Deprecated options:
        --console                    Console runner (use --runner).
        --gtk                        GTK runner (use --runner).
        --fox                        Fox runner (use --runner).

Help says --force should be a valid option.

$ rails g controller -h
Usage:
  rails generate controller NAME [action action] [options]

Options:
      [--helper]                # Indicates when to generate helper
                                # Default: true
      [--skip-namespace]        # Skip namespace (affects only isolated applications)
  -t, [--test-framework=NAME]   # Test framework to be invoked
                                # Default: test_unit
  -e, [--template-engine=NAME]  # Template engine to be invoked
                                # Default: erb

Runtime options:
  -q, [--quiet]    # Supress status output
  -f, [--force]    # Overwrite files that already exist
  -s, [--skip]     # Skip files that already exist
  -p, [--pretend]  # Run but do not make any changes

Description:
    Stubs out a new controller and its views. Pass the controller name, either
    CamelCased or under_scored, and a list of views as arguments.

    To create a controller within a module, specify the controller name as a
    path like 'parent_module/controller_name'.

    This generates a controller class in app/controllers and invokes helper,
    template engine and test framework generators.

Example:
    `rails generate controller CreditCard open debit credit close`

    Credit card controller with URLs like /credit_card/debit.
        Controller:      app/controllers/credit_card_controller.rb
        Functional Test: test/functional/credit_card_controller_test.rb
        Views:           app/views/credit_card/debit.html.erb [...]
        Helper:          app/helpers/credit_card_helper.rb
Test::Unit automatic runner.
Usage: script/rails [options] [-- untouched arguments]

    -r, --runner=RUNNER              Use the given RUNNER.
                                     (c[onsole], f[ox], g[tk], g[tk]2, t[k])
    -n, --name=NAME                  Runs tests matching NAME.
                                     (patterns may be used).
    -t, --testcase=TESTCASE          Runs tests in TestCases matching TESTCASE.
                                     (patterns may be used).
    -I, --load-path=DIR[:DIR...]     Appends directory list to $LOAD_PATH.
    -v, --verbose=[LEVEL]            Set the output level (default is verbose).
                                     (s[ilent], p[rogress], n[ormal], v[erbose])
        --                           Stop processing options so that the
                                     remaining options will be passed to the
                                     test.
    -h, --help                       Display this help.

Deprecated options:
        --console                    Console runner (use --runner).
        --gtk                        GTK runner (use --runner).
        --fox                        Fox runner (use --runner).