¡rake abortado! método indefinido `map 'para: name: Symbol

Question

Estoy tratando de pasar argumentos a una tarea de Rake y acceder a mi modelo como se menciona en" How to pass command line arguments to a rake task "y" Do rails rake tasks provide access to ActiveRecord models? ".

Sin embargo la adición de => :environment a este código:

require 'rake' 

namespace :genre do 
    desc "Add a genre" 
    task :add, :genre_id, :name => :environment do |t, args| 
     puts args.name 
    end 
end 

me da este error al ejecutar la tarea:

rake genre:add['1','Abc'] 
rake aborted! 
undefined method `map' for :name:Symbol 

(See full trace by running task with --trace) 

Si elimino => :environment funciona muy bien.

---

ACTUALIZACIÓN:

TRACE:

rake --trace genre:add['1','Abc'] 
rake aborted! 
undefined method `map' for :name:Symbol 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/task.rb:254:in `set_arg_names' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/task_manager.rb:29:in `define_task' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/task.rb:310:in `define_task' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/dsl_definition.rb:32:in `task' 
/private/var/www/html/someapp.com/subdomains/someapp.heroku.com/someapp/lib/tasks/genre.rake:5:in `block in <top (required)>' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/task_manager.rb:207:in `in_namespace' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/dsl_definition.rb:102:in `namespace' 
/private/var/www/html/someapp.com/subdomains/someapp.heroku.com/someapp/lib/tasks/genre.rake:3:in `<top (required)>' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/railties-3.2.3/lib/rails/engine.rb:425:in `load' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/railties-3.2.3/lib/rails/engine.rb:425:in `block in load_tasks' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/railties-3.2.3/lib/rails/engine.rb:425:in `each' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/railties-3.2.3/lib/rails/engine.rb:425:in `load_tasks' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/railties-3.2.3/lib/rails/application.rb:145:in `load_tasks' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/railties-3.2.3/lib/rails/railtie/configurable.rb:30:in `method_missing' 
/private/var/www/html/someapp.com/subdomains/someapp.heroku.com/someapp/Rakefile:7:in `<top (required)>' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/rake_module.rb:25:in `load' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/rake_module.rb:25:in `load_rakefile' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/application.rb:501:in `raw_load_rakefile' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/application.rb:82:in `block in load_rakefile' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/application.rb:81:in `load_rakefile' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/application.rb:65:in `block in run' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/bin/rake:19:in `load' 
/Users/user/.rvm/gems/ruby-1.9.2-p318/bin/rake:19:in `<main>' 

Answer 1

parece que su sintaxis está apagado. Pruebe:

task :add, [:genre_id, :name] => :environment do |t, args|