From 1a303c03edd53d0c848fc72861cb522a0edc9e51 Mon Sep 17 00:00:00 2001
From: Akira Matsuda <ronnie@dio.jp>
Date: Tue, 20 Oct 2020 16:35:59 +0900
Subject: [PATCH] Load locale files for available locales only

---
 lib/faker.rb        | 14 +++++++++++---
 test/test_locale.rb | 15 +++++++++++++++
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/lib/faker.rb b/lib/faker.rb
index 981f9f4dc3..9e81318ae0 100644
--- a/lib/faker.rb
+++ b/lib/faker.rb
@@ -13,11 +13,19 @@ module Faker
 
   class << self
     def load_i18n
-      unless @i18n_loaded
+      return if @i18n_loaded
+
+      if I18n.available_locales&.any?
+        # We expect all locale .yml files to have the locale name in its filename
+        I18n.load_path += ::Dir[::File.join(__dir__, 'locales', "{#{I18n.available_locales.join(',')}}.yml")]
+        # Or to be located in a directory with the locale name
+        I18n.load_path += ::Dir[::File.join(__dir__, 'locales', "{#{I18n.available_locales.join(',')}}/*.yml")]
+      else
         I18n.load_path += ::Dir[::File.join(__dir__, 'locales', '**/*.yml')]
-        I18n.reload! if I18n.backend.initialized?
-        @i18n_loaded = true
       end
+
+      I18n.reload! if I18n.backend.initialized?
+      @i18n_loaded = true
     end
   end
 
diff --git a/test/test_locale.rb b/test/test_locale.rb
index 3c7b362ed7..a55de7649b 100644
--- a/test/test_locale.rb
+++ b/test/test_locale.rb
@@ -78,4 +78,19 @@ def test_regex
   def test_available_locales
     assert I18n.locale_available?('en-GB')
   end
+
+  def test_load_i18n
+    Faker.instance_variable_set :@i18n_loaded, nil
+    available_locales_was = I18n.available_locales
+
+    I18n.available_locales = %i[en ja id]
+    Faker.load_i18n
+    I18n.eager_load!
+
+    assert Faker.instance_variable_get(:@i18n_loaded)
+    assert_equal %i[en id ja], I18n.backend.translations.keys.sort
+  ensure
+    I18n.available_locales = available_locales_was
+    Faker.instance_variable_set :@i18n_loaded, nil
+  end
 end