When I run rails s:
/Users/galli01anthony/.rvm/gems/ruby-2.1.3/gems/devise-3.2.4/lib/devise/rails/routes.rb:455:in
`ensure in with_devise_exclusive_scope': undefined method `merge!' for
#<ActionDispatch::Routing::Mapper::Scope:0x007f8743e19020> (NoMethodError)
When I run rake db:reset or db:migrate or db:setup:
rake aborted!
NoMethodError: undefined method `merge!' for #<ActionDispatch::Routing::Mapper::Scope:0x007fca8d3f2780>
It seems like the issue was fixed with this PR https://github.com/plataformatec/devise/pull/3153 a while ago. Update the devise gem in your application (if possible).
Change the version of devise in your Gemfile to at least 3.4.0:
gem 'devise', '~> 3.4.0' # or later
Then run:
bundle update devise
Update: Devise was updated to version 3.5.x a while ago and 4.0 will be released soon (see all version on RubyGems.org). That said you may want to define at least a version 3.5.x in your Gemfile:
gem 'devise', '~> 3.5.0'
Or just load the newest version that is possible:
gem 'devise', '> 3.4'
follow by a bundle update devise
recently updated https://github.com/plataformatec/devise/pull/3153#issuecomment-71185519
Gemfile
gem 'devise', github: 'plataformatec/devise'
It was still producing the error for me with devise 3.4.1.
Removing :confirmable in the User model fixed the problem.
