Load

Trying to reproduce:

F, [] FATAL -- : [] NameError (uninitialized constant #<Class:0x0055a1368249c0>::Chimp):
F, [] FATAL -- : [] app/models/advocate/self_code.rb:7:in `add_to_mailchimp'

  6   def add_to_mailchimp
  7     list = Chimp::List.new(Chimp::Settings.list_id('amigos'))
  8     begin

which only happens in production.

td/dl

With Rails 5.0, it no longer makes sense to place any application code in the lib directory. Make a home for it in the app directory. In particular, note this last commit.

how

This repository reproduces the problem in a rails app generated from scratch, as simply as possible.
During this excercise, I went scratching around in the Rails release notes for things to do with loading and autoloading and load paths. I found this:

"Disabled autoloading of classes in production environment."

in the Rails 5.0 release notes. It references a commit. That commit gave me a clue.

First, I was able to reproduce the problem in test by editing “config/environments/test.rb” as follows:

# config.eager_load = false
# DOUG, DON'T COMMIT THIS CHANGE
config.eager_load = true

That is simply to (temporarily) enable eager loading when running tests. Aha! The error manifests itself differently– rspec throws a stack trace and will not execute –however the fault is the same. The stack trace from rspec shows that it isn’t able to load the classes from lib.

Now in order to get the code in lib working to begin with, I had added the lib directory to the autoloaded paths. I did this by updating config/application.rb with the line, config.autoload_paths += Dir["#{config.root}/lib/"]. The Rails configuration guide suggests this, sort of. Or I’m not sure where I picked that up. It’s an old thing.

With Rails 5.0 and eager loading, it is necessary also to add the same paths to a second configuration, “config.eager_load_paths”. Eager loading is the default for the production environment (see config/environments/production.rb).

Adding the line, config.eager_load_paths += Dir["#{config.root}/lib/"] in config/application.rb solved the problem.

but

In the Rails 5.0 generated application you’ll find directories, assets and tasks within the lib directory. Does it make sense to eager-load those? Probably not.

Here’s a second fix that made everything simple.

Instead of putting my “role_api” directory in “lib”, I made a directory in app called “services” (app/services). Then I moved the role_api directory from lib to app/services (app/services/role_api) and deleted the two configuration lines from config/application.rb.

Running the tests still worked, and then I reverted the config.eager_load change I had made in config/environments/test.rb.

in sum

The moral of the story, for me, is that, with Rails 5.0, it no longer makes sense to place any application code in the lib directory. Instead, make a home for it in the app directory.

Some details

The content of this repository was created with:

rails new load -M -C --skip-spring --skip-listen --skip-turbolinks

The prisoner resource was generated with:

rails g resource prisoner name:string rank:string serial_number:string --no-helper --no-javascripts --no-stylesheets