Add new Rails/I18nLocaleTexts cop

Author: fatkodima

changelog/new_add_i18n_locale_texts_cop.md

@@ -0,0 +1 @@
+* [#624](https://github.com/rubocop/rubocop-rails/issues/624): Add new `Rails/I18nLocaleTexts` cop. ([@fatkodima][])

config/default.yml

@@ -455,6 +455,12 @@ Rails/I18nLocaleAssignment:
     - spec/**/*.rb
     - test/**/*.rb
 
+Rails/I18nLocaleTexts:
+  Description: 'Enforces use of I18n and locale files instead of locale specific strings.'
+  StyleGuide: 'https://rails.rubystyle.guide/#locale-texts'
+  Enabled: pending
+  VersionAdded: '<<next>>'
+
 Rails/IgnoredSkipActionFilterOption:
   Description: 'Checks that `if` and `only` (or `except`) are not used together as options of `skip_*` action filter.'
   Reference: 'https://api.rubyonrails.org/classes/AbstractController/Callbacks/ClassMethods.html#method-i-_normalize_callback_options'

lib/rubocop/cop/rails/i18n_locale_texts.rb

@@ -0,0 +1,110 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module Rails
+      # Enforces use of I18n and locale files instead of locale specific strings.
+      #
+      # @example
+      #   # bad
+      #   class User < ApplicationRecord
+      #     validates :email, presence: { message: "must be present" }
+      #   end
+      #
+      #   # good
+      #   # config/locales/en.yml
+      #   # en:
+      #   #   activerecord:
+      #   #     errors:
+      #   #       models:
+      #   #         user:
+      #   #           blank: "must be present"
+      #
+      #   class User < ApplicationRecord
+      #     validates :email, presence: true
+      #   end
+      #
+      #   # bad
+      #   class PostsController < ApplicationController
+      #     def create
+      #       # ...
+      #       redirect_to root_path, notice: "Post created!"
+      #     end
+      #   end
+      #
+      #   # good
+      #   # config/locales/en.yml
+      #   # en:
+      #   #   posts:
+      #   #     create:
+      #   #       success: "Post created!"
+      #
+      #   class PostsController < ApplicationController
+      #     def create
+      #       # ...
+      #       redirect_to root_path, notice: t(".success")
+      #     end
+      #   end
+      #
+      #   # bad
+      #   class UserMailer < ApplicationMailer
+      #     def welcome(user)
+      #       mail(to: user.email, subject: "Welcome to My Awesome Site")
+      #     end
+      #   end
+      #
+      #   # good
+      #   # config/locales/en.yml
+      #   # en:
+      #   #   user_mailer:
+      #   #     welcome:
+      #   #       subject: "Welcome to My Awesome Site"
+      #
+      #   class UserMailer < ApplicationMailer
+      #     def welcome(user)
+      #       mail(to: user.email)
+      #     end
+      #   end
+      #
+      class I18nLocaleTexts < Base
+        MSG = 'Move locale texts to the locale files in the `config/locales` directory.'
+
+        RESTRICT_ON_SEND = %i[validates redirect_to []= mail].freeze
+
+        def_node_search :validation_message, <<~PATTERN
+          (pair (sym :message) $str)
+        PATTERN
+
+        def_node_search :redirect_to_flash, <<~PATTERN
+          (pair (sym {:notice :alert}) $str)
+        PATTERN
+
+        def_node_matcher :flash_assignment?, <<~PATTERN
+          (send (send nil? :flash) :[]= _ $str)
+        PATTERN
+
+        def_node_search :mail_subject, <<~PATTERN
+          (pair (sym :subject) $str)
+        PATTERN
+
+        def on_send(node)
+          case node.method_name
+          when :validates
+            validation_message(node) do |text_node|
+              add_offense(text_node)
+            end
+            return
+          when :redirect_to
+            text_node = redirect_to_flash(node).to_a.last
+          when :[]=
+            text_node = flash_assignment?(node)
+          when :mail
+            text_node = mail_subject(node).to_a.last
+          end
+
+          add_offense(text_node) if text_node
+        end
+      end
+    end
+  end
+end

lib/rubocop/cop/rails_cops.rb

@@ -55,6 +55,7 @@
 require_relative 'rails/http_status'
 require_relative 'rails/i18n_lazy_lookup'
 require_relative 'rails/i18n_locale_assignment'
+require_relative 'rails/i18n_locale_texts'
 require_relative 'rails/ignored_skip_action_filter_option'
 require_relative 'rails/index_by'
 require_relative 'rails/index_with'

spec/rubocop/cop/rails/i18n_locale_texts_spec.rb

@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+RSpec.describe RuboCop::Cop::Rails::I18nLocaleTexts, :config do
+  it 'registers an offense when using `validates` with text messages' do
+    expect_offense(<<~RUBY)
+      validates :email, presence: { message: "must be present" },
+                                             ^^^^^^^^^^^^^^^^^ Move locale texts to the locale files in the `config/locales` directory.
+        format: { with: /@/, message: "not an email" },
+                                      ^^^^^^^^^^^^^^ Move locale texts to the locale files in the `config/locales` directory.
+        length: { maximum: 64 }
+    RUBY
+  end
+
+  it 'does not register an offense when using `validates` with localized messages' do
+    expect_no_offenses(<<~RUBY)
+      validates :email, presence: { message: :email_missing },
+        format: { with: /@/, message: I18n.t('email_format') },
+        length: { maximum: 64 }
+    RUBY
+  end
+
+  it 'registers an offense when using `redirect_to` with text flash messages' do
+    expect_offense(<<~RUBY)
+      redirect_to root_path, notice: "Post created!"
+                                     ^^^^^^^^^^^^^^^ Move locale texts to the locale files in the `config/locales` directory.
+    RUBY
+  end
+
+  it 'does not register an offense when using `redirect_to` with localized flash messages' do
+    expect_no_offenses(<<~RUBY)
+      redirect_to root_path, notice: t(".success")
+    RUBY
+  end
+
+  it 'registers an offense when assigning to `flash` text messages' do
+    expect_offense(<<~RUBY)
+      flash[:notice] = "Post created!"
+                       ^^^^^^^^^^^^^^^ Move locale texts to the locale files in the `config/locales` directory.
+    RUBY
+  end
+
+  it 'does not register an offense when assigning to `flash` localized messages' do
+    expect_no_offenses(<<~RUBY)
+      flash[:notice] = t(".success")
+    RUBY
+  end
+
+  it 'registers an offense when using `mail` with text subject' do
+    expect_offense(<<~RUBY)
+      mail(to: user.email, subject: "Welcome to My Awesome Site")
+                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Move locale texts to the locale files in the `config/locales` directory.
+    RUBY
+  end
+
+  it 'does not register an offense when using `mail` with localized subject' do
+    expect_no_offenses(<<~RUBY)
+      mail(to: user.email)
+      mail(to: user.email, subject: t("mailers.users.welcome"))
+    RUBY
+  end
+end