why do I get uninitialized constant Devise name Error when running webrick server?

Question

In my application I have used ruby 1.9.2 and rails 3.0.3 and have also installed Devise gem.The problem begins when I run the Webrick server I get uninitialized constant Devise name Error.

       /home/app/Workspace/project/Library_Management/Library_Management/config/initializers/devise.rb:3:in `<top (required)>': uninitialized constant Devise (NameError)
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.9/lib/rails/engine.rb:201:in `block (2 levels) in <class:Engine>'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.9/lib/rails/engine.rb:200:in `each'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.9/lib/rails/engine.rb:200:in `block in <class:Engine>'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.9/lib/rails/initializable.rb:25:in `instance_exec'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.9/lib/rails/initializable.rb:25:in `run'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.9/lib/rails/initializable.rb:50:in `block in run_initializers'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.9/lib/rails/initializable.rb:49:in `each'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.9/lib/rails/initializable.rb:49:in `run_initializers'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.9/lib/rails/application.rb:134:in `initialize!'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.9/lib/rails/application.rb:77:in `method_missing'
from /home/app/Workspace/project/Library_Management/Library_Management/config/environment.rb:5:in `<top (required)>'
from /home/app/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:54:in `require'
from /home/app/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:54:in `require'
from /home/app/Workspace/project/Library_Management/Library_Management/config.ru:3:in `block in <main>'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.2.3/lib/rack/builder.rb:46:in `instance_eval'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.2.3/lib/rack/builder.rb:46:in `initialize'
from /home/app/Workspace/project/Library_Management/Library_Management/config.ru:1:in `new'
from /home/app/Workspace/project/Library_Management/Library_Management/config.ru:1:in `<main>'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.2.3/lib/rack/builder.rb:35:in `eval'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.2.3/lib/rack/builder.rb:35:in `parse_file'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.2.3/lib/rack/server.rb:162:in `app'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.2.3/lib/rack/server.rb:253:in `wrapped_app'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/rack-1.2.3/lib/rack/server.rb:204:in `start'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.9/lib/rails/commands/server.rb:65:in `start'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.9/lib/rails/commands.rb:30:in `block in <top (required)>'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.9/lib/rails/commands.rb:27:in `tap'
from /home/app/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.9/lib/rails/commands.rb:27:in `<top (required)>'
from /home/app/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:58:in `require'
from /home/app/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:58:in `rescue in require'
from /home/app/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:35:in `require'

Thanks

Solution 1

Check your config/application.rb, you need to add require 'devise' and you should be fine.

Solution 2

In case you are writing an engine which has its own devise config, just add

require 'devise'

on the beginning of devise initializer. In my case I had no devise requirement within application :)

Cheers

Solution 3

Make sure you've listed Devise in your Gemfile and run bundle install.

Solution 4

I had a similar issue and i found this https://github.com/plataformatec/devise

It says you have to do

rails generate devise:install

Following "Getting Started" on that page got me going

Solution 5

I got an error like that when I had a custom devise controller to override the 'new' method to do some custom stuff, and forgot to use 'super'

Do you have a custom controller?

View more solutions

Comments

[Addicted]

yes i have listed devise n also ran bundle install but still i am getting the same error..

[Addicted]

Inside the Configuration/application.rb i added the line require 'devise' and was able to fix the problem

[Automatico]

Also, try "bundle update" as it will be a bit more aggressive in installing updates. It updates all gems with all dependencies which often can help ironing out bugs like this. HAve a look at ryanbigg.com/2011/01/why-you-should-run-bundle-update

[Eskim0]

I am still having this same problem- strangely however only in my development environment. I just need to restart my development server and that clears it. But after one user login attempt it blows up again. I tried the includes as listed above but they seem like they should not be needed -and they don't help for me.