Add a cop to enforce internationalization

[pirj]

#620 brought up a problem with user-facing string appearing directly in models.

class Foo < ApplicationRecord
  belongs_to :bar
  validates :bar, presence: { message: 'show me the way to the next whiskey bar' }
end

Describe the solution you'd like

Add a cop that enforces https://rails.rubystyle.guide/#locale-texts, at least for basic cases for the start.

No strings or other locale specific settings should be used in the views, models and controllers. These texts should be moved to the locale files in the config/locales directory.

[fatkodima]

@pirj How do you think this will be better implemented? Just checking for strings in models/controllers/etc would give a lot of false positives.

So this should be implemented as checking specific methods and their arguments? Like validates messages, redirect_to notices/alerts/errors, mailers subjects, etc?

[pirj]

Exactly.

[andyw8]

I think this would be a useful cop, but should be disabled by default. The majority of apps only target a single locale, and this approach requires extra effort.

(and I would support updating the styleguide to reflect this nuance).

[pirj]

this approach requires extra effort

Fair enough. Some thoughts aloud.

Even though the app might be a single locale, it's easier for non-tech staff to edit a singe YAML file to fix copy rather than update code. I've seen this in practice a couple of times. Surely, adding new entries to model validation will still require developer's effort, due to a non-trivial structure, but updating existing non-default ones is possible.

When the cop is disabled by default, it's nearly ever used. Some cops just don't apply in certain cases, and it's a usual routine to disable them on a new project, e.g. Metrics/BlockSize for specs/**/*.rb.

It reminds me of "the business logic should naturally reside in the model" and the "keep complicated formatting logic out of views". It's tempting to have logic in controllers and views, and putting it to where it belongs is an extra effort, too.