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