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/开发者_开发问答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 How to fix the uninitialized constant Rake::DSL problem on Heroku?

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: Undefined method 'task' using Rake 0.9.0

---

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.