Posted about 6 years ago. Visible to the public.

Fixing "uninitialized constant ActiveSupport::Dependencies::Mutex (NameError)"

RubyGems 1.6.0 has undergone some changes which may cause Rails 2.x applications to break with an error like this one (e.g. when running script/server):
/usr/lib/ruby/gems/1.8/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:55: uninitialized constant ActiveSupport::Dependencies::Mutex (NameError)

Fix it by adding the following not only to your environment.rb but also into your script/server file, in both cases before boot.rb is required.
require 'thread'

If you still get the error above you can also add require 'thread' in your boot.rb after the RAILS_ROOT constant was defined.
RAILS_ROOT = "#{File.dirname(FILE)}/.." unless defined?(RAILS_ROOT)
require 'thread'

Once an application no longer requires constant development, it needs periodic maintenance for stable and secure operation. makandra offers monthly maintenance contracts that let you focus on your business while we make sure the lights stay on.

Author of this card:

Ulrich Berkmueller
About this deck:
We are makandra and do test-driven, agile Ruby on Rails software development.
License for source code
Posted by Ulrich Berkmueller to makandropedia