Add compatibility for Ruby 2.4 `to_time` changes

In Ruby 2.4 the `to_time` method for both `DateTime` and `Time` will
preserve the timezone of the receiver when converting to an instance
of `Time`. Since Rails 5.0 will support Ruby 2.2, 2.3 and later we
need to introduce a compatibility layer so that apps that upgrade do
not break. New apps will have a config initializer file that defaults
to match the new Ruby 2.4 behavior going forward.

For information about the changes to Ruby see:
https://bugs.ruby-lang.org/issues/12189
https://bugs.ruby-lang.org/issues/12271

Fixes #24617.

1 files changed, 28 insertions, 0 deletions

diff --git a/railties/test/generators/app_generator_test.rb b/railties/test/generators/app_generator_test.rb
index 2d9867fa9d..25a8635e7d 100644
--- a/railties/test/generators/app_generator_test.rb
+++ b/railties/test/generators/app_generator_test.rb
@@ -257,6 +257,34 @@ class AppGeneratorTest < Rails::Generators::TestCase
     end
   end
 
+  def test_rails_update_does_not_create_to_time_preserves_timezone
+    app_root = File.join(destination_root, 'myapp')
+    run_generator [app_root]
+
+    FileUtils.rm("#{app_root}/config/initializers/to_time_preserves_timezone.rb")
+
+    stub_rails_application(app_root) do
+      generator = Rails::Generators::AppGenerator.new ["rails"], [], destination_root: app_root, shell: @shell
+      generator.send(:app_const)
+      quietly { generator.send(:update_config_files) }
+      assert_no_file "#{app_root}/config/initializers/to_time_preserves_timezone.rb"
+    end
+  end
+
+  def test_rails_update_does_not_remove_to_time_preserves_timezone_if_already_present
+    app_root = File.join(destination_root, 'myapp')
+    run_generator [app_root]
+
+    FileUtils.touch("#{app_root}/config/initializers/to_time_preserves_timezone.rb")
+
+    stub_rails_application(app_root) do
+      generator = Rails::Generators::AppGenerator.new ["rails"], [], destination_root: app_root, shell: @shell
+      generator.send(:app_const)
+      quietly { generator.send(:update_config_files) }
+      assert_file "#{app_root}/config/initializers/to_time_preserves_timezone.rb"
+    end
+  end
+
   def test_rails_update_does_not_create_ssl_options_by_default
     app_root = File.join(destination_root, 'myapp')
     run_generator [app_root]