I ran into the following problem in my application when I went from my dev environment to my staging environment. Modules and classes that were previously autoloaded just fine in dev ended up with a strange error in staging:
NameError: uninitialized constant Rails::Initializer::...
Weird.
Well, I managed to reproduce it, and here is the procedure. I'm wondering if the approach I'm using to setup environment-specific values for these constants is the culprit, and maybe there's a better way. Or maybe this is some sort of wacky bug? Anyway, here's the procedure. Let me know what you think.
--->8--- cut here --->8---
1) Create a new Rails app, e. g. $ rails constant
2) Edit the environment.rb file to add your own module with configuration constant default values with the idea you could "override" these by specifying them in the specific environment file:
At the end of config/environment.rb, add:
module AppConstants IMPORTANT_VALUE = "x" unless defined?(AppConstants::IMPORTANT_VALUE) end
3) Create a Ruby module in the file lib/app_constants/list.rb, noting the "top level" name of the module matches the one specified in the environment file:
module AppConstants module List LIST_CONSTANT = "list_constant" end end
3) Fire up the console and probe the constant values:
Loading development environment.
AppConstants::List::LIST_CONSTANT
=> "list_constant"
AppConstants::IMPORTANT_VALUE
=> "x"
4) Quit from the console and add development-specific value for the constant defined in the environment file:
At the end of config/environments/development.rb, add:
module AppConstants IMPORTANT_VALUE = "definitely_not_x" end
5) Fire up the console again and probe the constant values:
Loading development environment.
AppConstants::List::LIST_CONSTANT
NameError: uninitialized constant Rails::Initializer::AppConstants::List from /usr/local/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/ active_support/dependencies.rb:263:in `load_missing_constant' from /usr/local/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/ active_support/dependencies.rb:452:in `const_missing' from (irb):1
AppConstants::IMPORTANT_VALUE
=> "definitely_not_x"
AppConstants::List::LIST_CONSTANT
NameError: uninitialized constant Rails::Initializer::AppConstants::List from /usr/local/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/ active_support/dependencies.rb:263:in `load_missing_constant' from /usr/local/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/ active_support/dependencies.rb:452:in `const_missing' from (irb):3