Use HashWithIndifferentAccess for enum values

[hdoan741]

Currently sorbet-rails uses T::Hash[T.any(String, Symbol), Integer] for enum values of a model. This works but the keys method would return an array of Symbol or String. Rails actually use HashWithIndifferentAccess, which guarantee (softly) that .keys would return an array of String.

It's blocking on the typedef of HashWithIndifferentAccess itself (which should/could be added to sorbet-typed)

[mattxwang]

Just curious - is this something we still want to resolve? It seems like ActiveSupport::HashWithIndifferentAccess now exists in sorbet-typed.

If so, happy to submit a PR!

[ghiculescu]

If so, happy to submit a PR!

Yes please!

[mattxwang]

This is my first time contributing to sorbet-rails, so forgive me for my lack of experience; I have a few questions!

My understanding is that to change the enum values for a model, I should look to change the types in active_record_enum.rb. Is that correct?

And to add - looking at the class def for ActiveSupport::HashWithIndifferentAccess, it subclasses their Hash type, which I'm not sure if it's a template type. Am I understanding how to use this properly?

i.e., should my new code look like this?

return_type = if value_type.length == 1
  "ActiveSupport::HashWithIndifferentAccess[#{value_type.first}]" # should this template type be here?
else
  "ActiveSupport::HashWithIndifferentAccess[T.any(#{value_type.join(', ')})]" # should this template type be here?
end

Or this; but, I feel like I'm losing some type information?

return_type = "ActiveSupport::HashWithIndifferentAccess"

[ghiculescu]

Hmm, this works fine, but as you say it loses type information.

But this does not.

@jeffcarbs you added the ActiveSupport::HashWithIndifferentAccess sig here but do you mind sharing how it's typically used?

[mattxwang]

While we wait for @jeffcarbs' answer, I'll note that the documentation for the class has examples where values are of different types:

rgb = ActiveSupport::HashWithIndifferentAccess.new

rgb[:black] = '#000000'

hash = ActiveSupport::HashWithIndifferentAccess.new(a: 1)

So I'm sure that there are typical uses where the values are different types.

This seems suitable for a generic type to me, which may make upgrading for users easier since it then just becomes a find-and-replace for T::Hash[T.any(String, Symbol), -> ActiveSupport::HashWithIndifferentAccess[. In that case, we also won't lose type information!

However, I'm not sure if this is bad practice since we're modifying how ActiveSupport::HashWithIndifferentAccess is defined internally, and that sounds like a breaking change to me. It also seems like generics are still an experimental feature in sorbet. My understanding is that we would lose generic types (type erasure?). It may be difficult to implement (though I'd still like to try if possible!).

Any thoughts @ghiculescu? I'm coming with little experience with sorbet or rails (my background is not in ruby) so any thoughts are appreciated!