`permit` and `optional` don't work very well together

[pareeohnos]

Describe the problem

If I mark an argument as optional but I still want to validate that if a value is supplied it is correct, I would assume that I can specify the option as optional, and also specify the permitted values. Unfortunately, if I do this and then don't supply the option, I get an error stating it is not a permitted value

Steps to reproduce the problem

argument :command do
  optional
  desc 'The command to run'
  permit %w[run config]
end

Actual behaviour

When using this combination, I get an error

Error: unpermitted value `` for 'command' argument: choose from run, config

Expected behaviour

If I don't supply the argument, it shouldn't validate if it is permitted given I have specified it is optional

Describe your environment

• OS version: OS X 11.5
• Ruby version: 2.5.3p105
• TTY::Option version: 0.2.0

---

Update: I can make it work by adding nil into the permitted list of options, but this feels a little unnecessary and hacky IMO. But this does work

argument :command do
  optional
  desc 'The command to run'
  permit [nil, 'run', 'config']
end

[piotrmurach]

Thank you for using tty-option and reporting this issue.

This is now fixed.