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diff --git a/doc/development/gotchas.md b/doc/development/gotchas.md index 40598eaff95..fbb6b0219aa 100644 --- a/doc/development/gotchas.md +++ b/doc/development/gotchas.md @@ -203,76 +203,6 @@ in an initializer. - Stack Overflow: [Why you should not write inline JavaScript](https://softwareengineering.stackexchange.com/questions/86589/why-should-i-avoid-inline-scripting) -## Auto loading - -Rails auto-loading on `development` differs from the load policy in the `production` environment. -In development mode, `config.eager_load` is set to `false`, which means classes -are loaded as needed. With the classic Rails autoloader, it is known that this can lead to -[Rails resolving the wrong class](https://guides.rubyonrails.org/v5.2/autoloading_and_reloading_constants.html#when-constants-aren-t-missed-relative-references) -if the class name is ambiguous. This can be fixed by specifying the complete namespace to the class. - -### Error prone example - -```ruby -# app/controllers/application_controller.rb -class ApplicationController < ActionController::Base - ... -end - -# app/controllers/projects/application_controller.rb -class Projects::ApplicationController < ApplicationController - ... - private - - def project - ... - end -end - -# app/controllers/projects/submodule/some_controller.rb -module Projects - module Submodule - class SomeController < ApplicationController - def index - @some_id = project.id - end - end - end -end -``` - -In this case, if for any reason the top level `ApplicationController` -is loaded but `Projects::ApplicationController` is not, `ApplicationController` -would be resolved to `::ApplicationController` and then the `project` method is -undefined, causing an error. - -#### Solution - -```ruby -# app/controllers/projects/submodule/some_controller.rb -module Projects - module Submodule - class SomeController < Projects::ApplicationController - def index - @some_id = project.id - end - end - end -end -``` - -By specifying `Projects::`, we tell Rails exactly what class we are referring -to and we would avoid the issue. - -NOTE: -This problem disappears as soon as we upgrade to Rails 6 and use the Zeitwerk autoloader. - -### Further reading - -- Rails Guides: [Autoloading and Reloading Constants (Classic Mode)](https://guides.rubyonrails.org/autoloading_and_reloading_constants_classic_mode.html) -- Ruby Constant lookup: [Everything you ever wanted to know about constant lookup in Ruby](https://cirw.in/blog/constant-lookup) -- Rails 6 and Zeitwerk autoloader: [Understanding Zeitwerk in Rails 6](https://medium.com/cedarcode/understanding-zeitwerk-in-rails-6-f168a9f09a1f) - ## Storing assets that do not require pre-compiling Assets that need to be served to the user are stored under the `app/assets` directory, which is later pre-compiled and placed in the `public/` directory. |