Class: RuboCop::Cop::Rails::Env

Inherits:
Base
  • Object
show all
Defined in:
lib/rubocop/cop/rails/env.rb

Overview

Checks for usage of Rails.env which can be replaced with Feature Flags

The cop does not flag Rails.env.local?, the built-in alias for "development or test" introduced in Rails 7.1. Unlike per-environment predicates such as development? or production?, local? expresses the intent of guarding code that must only ever run in development or test (sanity checks, devtools, seed data) rather than gating an environment rollout, so a Feature Flag is not a suitable replacement.

Examples:


# bad
Rails.env.production? || Rails.env.development?

# good
if FeatureFlag.enabled?(:new_feature)
  # new feature code
end

# good
raise 'This should never run in production' unless Rails.env.local?

Constant Summary collapse

MSG = 
'Use Feature Flags or config instead of `Rails.env`.'
RESTRICT_ON_SEND = 
%i[env].freeze
ALLOWED_LIST =

This allow list is derived from: (Rails.env.methods - Object.instance_methods).select { |m| m.to_s.end_with?('?') } and then removing the environment specific methods like development?, test?, and production?. local? is kept on the allow list because it intentionally expresses "development or test" rather than a single environment rollout.

Set.new(
  %i[
    unicode_normalized?
    exclude?
    empty?
    acts_like_string?
    include?
    is_utf8?
    casecmp?
    match?
    starts_with?
    ends_with?
    start_with?
    end_with?
    valid_encoding?
    ascii_only?
    between?
    local?
  ]
).freeze

Instance Method Summary collapse

Instance Method Details

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/rails/env.rb', line 57

def on_send(node)
  return unless node.receiver&.const_name == 'Rails'

  parent = node.parent
  return unless parent.respond_to?(:predicate_method?) && parent.predicate_method?

  return if ALLOWED_LIST.include?(parent.method_name)

  add_offense(parent)
end