Ruby on Rails and Rake problems: uninitialized constant Rake::DSL

I'm having a really frustrating issue: Rake is being dumb.

Here's how the problem comes about:

$ rails new test_app
$ rails generate scaffold new_scaffold field1:string field2:text

Both of those work just fine, but then when I do this,

$ rake db:migrate

I get the following error.

(in /home/mikhail/test_app)
rake aborted!
uninitialized constant Rake::DSL
/usr/lib/ruby/1.9.1/rake.rb:2482:in `const_missing'
/usr/lib/ruby/gems/1.9.1/gems/rake-0.9.0/lib/rake/tasklib.rb:8:in `<class:TaskLib>'
/usr/lib/ruby/gems/1.9.1/gems/rake-0.9.0/lib/rake/tasklib.rb:6:in `<module:Rake>'
/usr/lib/ruby/gems/1.9.1/gems/rake-0.9.0/lib/rake/tasklib.rb:3:in `<top (required)>'
/usr/lib/ruby/gems/1.9.1/gems/rake-0.9.0/lib/rake/rdoctask.rb:20:in `require'
/usr/lib/ruby/gems/1.9.1/gems/rake-0.9.0/lib/rake/rdoctask.rb:20:in `<top (required)>'
/usr/lib/ruby/gems/1.9.1/gems/railties-3.0.7/lib/rails/tasks/documentation.rake:1:in `require'
/usr/lib/ruby/gems/1.9.1/gems/railties-3.0.7/lib/rails/tasks/documentation.rake:1:in `<top (required)>'
/usr/lib/ruby/gems/1.9.1/gems/railties-3.0.7/lib/rails/tasks.rb:15:in `load'
/usr/lib/ruby/gems/1.9.1/gems/railties-3.0.7/lib/rails/tasks.rb:15:in `block in <top (required)>'
/usr/lib/ruby/gems/1.9.1/gems/railties-3.0.7/lib/rails/tasks.rb:6:in `each'
/usr/lib/ruby/gems/1.9.1/gems/railties-3.0.7/lib/rails/tasks.rb:6:in `<top (required)>'
/usr/lib/ruby/gems/1.9.1/gems/railties-3.0.7/lib/rails/application.rb:214:in `require'
/usr/lib/ruby/gems/1.9.1/gems/railties-3.0.7/lib/rails/application.rb:214:in `initialize_tasks'
/usr/lib/ruby/gems/1.9.1/gems/railties-3.0.7/lib/rails/application.rb:139:in `load_tasks'
/usr/lib/ruby/gems/1.9.1/gems/railties-3.0.7/lib/rails/application.rb:77:in `method_missing'
/home/mikhail/test_app/Rakefile:7:in `<top (required)>'
/usr/lib/ruby/1.9.1/rake.rb:2373:in `load'
/usr/lib/ruby/1.9.1/rake.rb:2373:in `raw_load_rakefile'
/usr/lib/ruby/1.9.1/rake.rb:2007:in `block in load_rakefile'
/usr/lib/ruby/1.9.1/rake.rb:2058:in `standard_exception_handling'
/usr/lib/ruby/1.9.1/rake.rb:2006:in `load_rakefile'
/usr/lib/ruby/1.9.1/rake.rb:1991:in `run'
/usr/bin/rake:31:in `<main>'

I've looked about the Internet for similar/same errors, and people have had them. Just no one ever seems to solve the problem!

How do I fix this problem?

A tweet from DHH earlier. Rake .9.0 breaks Rails and several other things, you need to:

gem "rake", "0.8.7"

in your Gemfile.

I made some research just after my previous answer (sorry, I must do before it).

All problems are solved with Rake gem 0.9.2.. I followed these steps:

• I installed gem install rake -v=0.9.2 (I had the 0.9.1 gem)

• removed the 0.9.1 with gem uninstall rake -v=0.9.1

• updated with bundle update

• then the db:migrate showed a warning, WARNING: Global access to Rake DSL methods is deprecated. Please....

  It was solved by adding the following to the Rake file.

   module ::YourApplicationName  
     class Application
       include Rake::DSL
     end
   end
  

• I ommited the module ::RakeFileUtils extend Rake::FileUtilsExtend option sugested by @databyte.

It means that the Rake gem 0.9.2 works fine!

Going through Chapter 2 of Railstutorial (demo_app) and ran into this problem. I tried all of the other answers listed here, but couldn't get it to work until I did this:

Put this in your Rakefile above require 'rake':

require 'rake/dsl_definition'

via https://stackoverflow.com/questions/6181312/how-to-fix-the-uninitialized-constant-rakedsl-problem-on-heroku/6263256#6263256

I also recommitted and pushed all files to Github and Heroku.

All I needed to do was use:

gem install rake

I had version 0.9.2 already, just needed installing.

Reinstall the rake gem and it should work fine:

gem uninstall rake -v=0.9.2 
gem install rake -v=0.9.2

If not, specify version '0.8.7' in your Gemfile.

If not using Bundler:

sudo gem install rake -v 0.8.7
sudo gem uninstall rake

Then choose to uninstall 0.9.0.

If like me you're stuck on rake 0.8.7, and you're using Rails 3.2.x then railties adds a requirement for Rake::DSL

To solve this, to the top of your Rakefile you should add:

module Rake
  module DSL
  end
end

I solved the same problem with the following steps:

In Gemfile:

gem 'rake', '0.9.2'

Then ran this on the console:

sudo bundle update rake

Then added the following lines to Rakefile:

require 'rake/dsl_definition'
include Rake::DSL

Rails 3.1.rc1 has been updated. For your own Rakefiles, you can add this before the call to load_tasks.

module ::YourApplicationName
  class Application
    include Rake::DSL
  end
end

module ::RakeFileUtils
  extend Rake::FileUtilsExt
end

https://gist.github.com/4cd2bbe68f98f2f0249f

UPDATE: Also noticed it's already answered here as well: https://stackoverflow.com/questions/5287121/undefined-method-task-using-rake-0-9-0-beta-4/5290331#5290331

I had the same issue and had to use the rake 0.8.7 gem instead of 0.9.0.

I am a Windows XP user and I had the same problem.

I entered gem "rake", "0.8.7" into the gemfile, and then typed the following from the command window.

bundle update rake

This fixed my problem.

1. Go to your project path
2. Type bundle install --path=vendor/bundle
3. Type bundle exec rake db:migrate

To start server type bundle exec rails s. Use bundle exec and you will be sure that you use right gems (required version) for your project. Also I would recommend you to add vendor/bundle to .gitignore if you use git and make alias for bundle exec. If you use zsh you can follow this approach

Same as Branstar above - thanks Branstar!

• OS: Windows Vista
• Level: Completely new to Ruby on Rails
• I already had Ruby 1.9.2 installed

I followed the instructions in Running Rails 3 on Windows.

All worked up until the "rake db:migrate" part which gave me the same output as original post.

I ran:

gem install rake

I ran again:

rake db:migrate

Then I was able to start the Ruby on Rails server and had everything in place.

Thanks again Branstar :-)

I feel for you (mikhailvs), it's really frustrating. I have been going crazy for almost one full day. I even uninstalled Ruby and all its dependent files and shutdown my PC, but I still got the same problem.

What I got from the error message is the problem with Rake 0.9.2. It seems like it wasn’t fully installed. So I had to reinstall gem install rake -v=0.9.2

I wasn’t sure if I have rake –v0.9.1 installed. So to make sure I’m safe I tried to remove that old version with gem uninstall rake -v=0.9.1. But is showed me the error message

ERROR:  While executing gem ... (Gem::InstallError)
    cannot uninstall, check `gem list -d rake`

OK, so I checked all Rake directories on my PC, and found I only had Rake 0.9.2. Then to check if everything went alright, I migrated with rake db:migrate. And it worked :)

I think I didn’t have Rake 0.9.1 because I clean-installed Ruby (rubyinstaller-1.9.2-p180 - on my Windows 7 system) and all gems as well. In the meantime Rake 0.9.2 wasn’t fully installed.

Uninstalling with "gem uninstall rake" worked for me, I had 2 versions installed, so I jest did a clean reinstall.

"rake db:create", to make sure the database exists and then "rake db:migrate" to seal the deal.

I had the same issue using Rake 0.9.2.2. I solved this problem by using bundle exec.

For Rails 2.3 editing lib/tasks/rspec.rake like in this commit worked for me:

https://github.com/dchelimsky/rspec-rails/pull/11/files

Install rake 0.8.7 and uninstall 0.9.2.2

$ gem install rake -v 0.8.7
$ gem uninstall rake -v 0.9.2.2

Now use

$ bundle exec rake db:migrate

i think this will help you ;)

Run

bundle exec rake db:migrate

it works for me.