"rails new -h" shows message in rails directory

railties/lib/rails/commands.rb

@@ -64,9 +64,13 @@ when 'application', 'runner'
   require "rails/commands/#{command}"
 
 when 'new'
-  puts "Can't initialize a new Rails application within the directory of another, please change to a non-Rails directory first.\n"
-  puts "Type 'rails' for help."
-  exit(1)
+  if ARGV.first.in?(['-h', '--help'])
+    require 'rails/commands/application'
+  else
+    puts "Can't initialize a new Rails application within the directory of another, please change to a non-Rails directory first.\n"
+    puts "Type 'rails' for help."
+    exit(1)
+  end
 
 when '--version', '-v'
   ARGV.unshift '--version'

railties/test/generators/app_generator_test.rb

@@ -84,6 +84,16 @@ class AppGeneratorTest < Rails::Generators::TestCase
     assert_equal false, $?.success?
   end
 
+  def test_application_new_show_help_message_inside_existing_rails_directory
+    app_root = File.join(destination_root, 'myfirstapp')
+    run_generator [app_root]
+    output = Dir.chdir(app_root) do
+      `rails new --help`
+    end
+    assert_match /rails new APP_PATH \[options\]/, output
+    assert_equal true, $?.success?
+  end
+
   def test_application_name_is_detected_if_it_exists_and_app_folder_renamed
     app_root       = File.join(destination_root, "myapp")
     app_moved_root = File.join(destination_root, "myapp_moved")