Fixed type error in 'brew audit'

[dduugg]

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---

Resolves:

$ brew audit --eval-all                                                                                           [master|⚑6]
vde:
  * fully scope test system calls, e.g. system "#{bin}/vde_switch"
Error: Return value: Expected type String, got type NilClass
Caller: /opt/homebrew/Library/Homebrew/cask/auditor.rb:68
Definition: /opt/homebrew/Library/Homebrew/cask/audit.rb:123
Please report this issue:
  https://docs.brew.sh/Troubleshooting
/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/2.6.0/gems/sorbet-runtime-0.5.10461/lib/types/configuration.rb:296:in `call_validation_error_handler_default'
/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/2.6.0/gems/sorbet-runtime-0.5.10461/lib/types/configuration.rb:303:in `call_validation_error_handler'
/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/2.6.0/gems/sorbet-runtime-0.5.10461/lib/types/private/methods/call_validation.rb:187:in `report_error'
/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/2.6.0/gems/sorbet-runtime-0.5.10461/lib/types/private/methods/call_validation.rb:166:in `validate_call'
/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/2.6.0/gems/sorbet-runtime-0.5.10461/lib/types/private/methods/_methods.rb:270:in `block in _on_method_added'
/opt/homebrew/Library/Homebrew/cask/auditor.rb:68:in `audit'
/opt/homebrew/Library/Homebrew/cask/auditor.rb:12:in `audit'
/opt/homebrew/Library/Homebrew/cask/cmd/audit.rb:115:in `block in audit_casks'
/opt/homebrew/Library/Homebrew/cask/cmd/audit.rb:113:in `to_h'
/opt/homebrew/Library/Homebrew/cask/cmd/audit.rb:113:in `audit_casks'
/opt/homebrew/Library/Homebrew/dev-cmd/audit.rb:239:in `audit'
/opt/homebrew/Library/Homebrew/brew.rb:93:in `<main>'

(I made the other necessary changes in oder to enable typed: true, which I consider to be a form of writing new tests, so I'm checking that box 😄)

[BrewTestBot]

Review period will end on 2023-02-28 at 00:00:00 UTC.

[BrewTestBot]

Review period skipped due to critical label.

[dduugg]

This is equivalent but marginally more readable imo (one fewer nesting of parens)

[Bo98]

This sort of weird multi-typing is probably something to address at some point (what's the difference between nil and false? when is true returned over Symbol?). Cask is littered with it so it's a big task to clean up everywhere.

There's a lot of nilable boolean stuff that is also very weird in places. It make sense for certain triple-state CLI arguments where explicit yes, explicit no and implicit default intentionally have three diferent behaviours. But some other bits I'm less sure it's necessary.

[MikeMcQuaid]

Makes sense to get to typed: true but I agree with @Bo98 that in general I think we accept/return nil way more often than we should.

[MikeMcQuaid]

Thanks again @dduugg!