safe navigation operator

[thewyzard44]

I would like to enable this nil checking syntax:

admins = node['maas']&.key?('admin_name') ? Array(node['maas']['admin_name']) : data_bag('metal_admins')

note the &. after the node['maas'] It essentially says if node['maas'] is nil, discontinue this expression and return nil.

This is the same as the elvis operator in other languages. (e.g. ?. in c#)

adding a '.rubocop.yml' to my project with:

AllCops:
  TargetRubyVersion: 2.4

effectively enables the use of &. however it introduces new cookstyle errors of recipes/default.rb:1:1: C: Missing magic comment # frozen_string_literal: true. in every other file in my cookbook. Now that chef 12 is EOL, all supported versions of chef are ruby 2.3+, of which, ruby 2.3 was the introduction of this operator.

I don't know how big of an issue that frozen_string_literal error is - if there were a PR to update the ruby version, could this error be suppressed at the same time without repurcussions?

otherwise, all of the code generators would need updated to include that 'frozen_string_literals' in all of their files in order to accept this update.

The same remains true if I use TargetRubyVersion: 2.3

[lamont-granquist]

both of those changes were committed to master in #45

[coderanger]

Also the way to write that in Chef is node.read('maas', 'admin_name')

[lamont-granquist]

i should really advertise that more broadly because i kinda fixed that but nobody uses it... (and i forget about it)