What is the problem with installing gem jquery-ui-rails?

Question

JavaScript

Error when trying to install jquery-ui-rails gem

Error installing jquery-ui-rails:
invalid gem: package is corrupt, exception while verifying: undefined method `size' for nil:NilClass (NoMethodError) in /home/nikita/.rvm/gems/ruby-2.2.1/cache/ jquery-ui-rails-5.0.5.gem

Googling yielded nothing, so I hope for your help. Tried both by adding to Gemfile and bundle install and through gem install jquery-ui-rails . Here is my Gemfile

source 'https://rubygems.org'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.1.2'

# Use sqlite3 as the database for Active Record
gem 'sqlite3'

# Use SCSS for stylesheets
gem 'sass-rails', '~> 4.0.0'

# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'

# Use CoffeeScript for .js.coffee assets and views
gem 'coffee-rails', '~> 4.0.0'

# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby

# Use jquery as the JavaScript library
gem 'jquery-rails'
gem 'jquery-ui-rails'
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'

# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 1.2'

group :doc do
  # bundle exec rake doc:rails generates the API under doc/api.
  gem 'sdoc', require: false
end

# Use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'

# Use unicorn as the app server
# gem 'unicorn'

# Use Capistrano for deployment
# gem 'capistrano', group: :development

# Use debugger
# gem 'debugger', group: [:development, :test]

Answer 1

Excerpt from https://github.com/joliss/jquery-ui-rails

Warning: This gem is incompatible with the jquery-rails gem before version 3.0.0! Strange things will happen if you use an earlier jquery-rails version. Run bundle list to ensure that you either aren't using jquery-rails, or at least version 3.0.0 of jquery-rails.