Do not load all application's task in generated engine

railties/lib/rails/generators/rails/plugin_new/templates/Rakefile

@@ -16,9 +16,6 @@ Rake::RDocTask.new(:rdoc) do |rdoc|
 end
 
 <% if  full? && !options[:skip_active_record] -%>
-namespace :app do
-  ENGINE_PATH = File.expand_path("..", __FILE__)
-  load File.expand_path("../<%= dummy_path -%>/Rakefile", __FILE__)
-end
-<% end -%>
-
+APP_RAKEFILE = File.expand_path("../<%= dummy_path -%>/Rakefile", __FILE__)
+load 'rails/tasks/engine.rake'
+<% end  %>

railties/lib/rails/tasks/engine.rake

@@ -0,0 +1,66 @@
+task "load_app" do
+  namespace :app do
+    load APP_RAKEFILE
+  end
+
+  if !defined?(ENGINE_PATH) || !ENGINE_PATH
+    ENGINE_PATH = find_engine_path(APP_RAKEFILE)
+  end
+end
+
+namespace :db do
+  task :reset     => [:load_app, :"app:db:reset"]
+
+  desc "Migrate the database (options: VERSION=x, VERBOSE=false)."
+  task :migrate         => [:load_app, :"app:db:migrate"]
+  task :"migrate:up"    => [:load_app, :"app:db:migrate:up"]
+  task :"migrate:down"  => [:load_app, :"app:db:migrate:down"]
+  task :"migrate:redo"  => [:load_app, :"app:db:migrate:redo"]
+  task :"migrate:reset" => [:load_app, :"app:db:migrate:reset"]
+
+  desc "Display status of migrations"
+  task :"migrate:status" => [:load_app, :"app:db:migrate:status"]
+
+  desc 'Create the database from config/database.yml for the current Rails.env (use db:create:all to create all dbs in the config)'
+  task :create        => [:load_app, :"app:db:create"]
+  task :"create:all"  => [:load_app, :"app:db:create:all"]
+
+  desc 'Drops the database for the current Rails.env (use db:drop:all to drop all databases)'
+  task :drop        => [:load_app, :"app:db:drop"]
+  task :"drop:all"  => [:load_app, :"app:db:drop:all"]
+
+  desc "Load fixtures into the current environment's database."
+  task :"fixtures:load" => [:load_app, :"app:db:fixtures:load"]
+
+  desc "Rolls the schema back to the previous version (specify steps w/ STEP=n)."
+  task :rollback => [:load_app, :"app:db:rollback"]
+
+  desc "Create a db/schema.rb file that can be portably used against any DB supported by AR"
+  task :"schema:dump" => [:load_app, :"app:db:schema:dump"]
+
+  desc "Load a schema.rb file into the database"
+  task :"schema:load" => [:load_app, :"app:db:schema:load"]
+
+  desc "Load the seed data from db/seeds.rb"
+  task :seed => [:load_app, :"app:db:seed"]
+
+  desc "Create the database, load the schema, and initialize with the seed data (use db:reset to also drop the db first)"
+  task :setup => [:load_app, :"app:db:setup"]
+
+  desc "Dump the database structure to an SQL file"
+  task :"structure:dump" => [:load_app, :"app:db:structure:dump"]
+
+  desc "Retrieves the current schema version number"
+  task :version => [:load_app, :"app:db:version"]
+end
+
+
+def find_engine_path(path)
+  return if path == "/"
+
+  if Rails::Engine.find(path)
+    path
+  else
+    find_engine_path(File.expand_path('..', path))
+  end
+end