No formatter for "" on .rubocop file

[huarmenta]

Expected behavior

rubocop should append -f / --format options when added to a .rubocop file and execute it correctly.

Actual behavior

When -f or --format option is added to a .rubocop file it shows the following error:

No formatter for " progress"
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rubocop-0.66.0/lib/rubocop/formatter/formatter_set.rb:87:in `builtin_formatter_class'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rubocop-0.66.0/lib/rubocop/formatter/formatter_set.rb:78:in `formatter_class'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rubocop-0.66.0/lib/rubocop/formatter/formatter_set.rb:60:in `add_formatter'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rubocop-0.66.0/lib/rubocop/runner.rb:321:in `block in formatter_set'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rubocop-0.66.0/lib/rubocop/runner.rb:320:in `each'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rubocop-0.66.0/lib/rubocop/runner.rb:320:in `formatter_set'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rubocop-0.66.0/lib/rubocop/runner.rb:76:in `ensure in inspect_files'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rubocop-0.66.0/lib/rubocop/runner.rb:77:in `inspect_files'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rubocop-0.66.0/lib/rubocop/runner.rb:39:in `run'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rubocop-0.66.0/lib/rubocop/cli.rb:174:in `execute_runner'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rubocop-0.66.0/lib/rubocop/cli.rb:75:in `execute_runners'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rubocop-0.66.0/lib/rubocop/cli.rb:47:in `run'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rubocop-0.66.0/exe/rubocop:13:in `block in <top (required)>'
/.rbenv/versions/2.6.1/lib/ruby/2.6.0/benchmark.rb:308:in `realtime'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rubocop-0.66.0/exe/rubocop:12:in `<top (required)>'
/.rbenv/versions/2.6.1/bin/rubocop:23:in `load'
/.rbenv/versions/2.6.1/bin/rubocop:23:in `<top (required)>'
/.rbenv/versions/2.6.1/lib/ruby/2.6.0/bundler/cli/exec.rb:74:in `load'
/.rbenv/versions/2.6.1/lib/ruby/2.6.0/bundler/cli/exec.rb:74:in `kernel_load'
/.rbenv/versions/2.6.1/lib/ruby/2.6.0/bundler/cli/exec.rb:28:in `run'
/.rbenv/versions/2.6.1/lib/ruby/2.6.0/bundler/cli.rb:463:in `exec'
/.rbenv/versions/2.6.1/lib/ruby/2.6.0/bundler/vendor/thor/lib/thor/command.rb:27:in `run'
/.rbenv/versions/2.6.1/lib/ruby/2.6.0/bundler/vendor/thor/lib/thor/invocation.rb:126:in `invoke_command'
/.rbenv/versions/2.6.1/lib/ruby/2.6.0/bundler/vendor/thor/lib/thor.rb:387:in `dispatch'
/.rbenv/versions/2.6.1/lib/ruby/2.6.0/bundler/cli.rb:27:in `dispatch'
/.rbenv/versions/2.6.1/lib/ruby/2.6.0/bundler/vendor/thor/lib/thor/base.rb:466:in `start'
/.rbenv/versions/2.6.1/lib/ruby/2.6.0/bundler/cli.rb:18:in `start'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-1.17.2/exe/bundle:30:in `block in <top (required)>'
/.rbenv/versions/2.6.1/lib/ruby/2.6.0/bundler/friendly_errors.rb:124:in `with_friendly_errors'
/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-1.17.2/exe/bundle:22:in `<top (required)>'
/.rbenv/versions/2.6.1/bin/bundle:23:in `load'
/.rbenv/versions/2.6.1/bin/bundle:23:in `<main>

Steps to reproduce the problem

1. $ touch .rubocop
2. Add --format progress to .rubocop file
3. $ [bundle exec] rubocop

RuboCop version

$ [bundle exec] rubocop -V
0.66.0 (using Parser 2.6.2.0, running on ruby 2.6.1 x86_64-darwin18)

[hoshinotsuyoshi]

I thought that RuboCop::Options#parse need to be fixed, so opened #7015 . 😃