Updating Extensions

How to upgrade your Spree extension to work with Spree 4

Zeitwerk compatibility

Zeitwerk is the new default code autoloader in Rails 6.

This doesn’t work well with the old approach to decorators (files that name ends with decorator.rb, eg. app/models/spree/order_decorator.rb) using class_eval.

To fix this we need to convert all class_eval decorators to modules and use Module.prepend. Also we need to name them properly according to Zeitwerk naming rules

Example of an old decorator:

app/models/spree/order_decorator.rb

Spree::Order.class_eval do
  has_many :new_custom_model

  def some_method
     # ...
  end
end

the same decorator in the new notation:

app/models/your_extension_name/order_decorator.rb

module YourExtensionName::OrderDecorator
  def self.prepended(base)
    base.has_many :new_custom_model
  end

  def some_method
    # ...
  end
end

Spree::Order.prepend(YourExtensionName::OrderDecorator)

Fixing Deface Overrides

Please remember to prepare versioned overrides for both Spree 3.x and 4.x, eg. https://github.com/spree-contrib/spree_static_content/commit/e4b9e4900024235158d0ec1a48a100b4732348ef

Spree 4 uses Bootstrap 4 and many partials and HTML structure changed compared to Spree 3.x.

Also - remember to add deface gem to gemspec as deface itself was removed as a dependency of Spree. eg. https://github.com/spree/spree_auth_devise/commit/d729689ca87d8586e541ffcc865ef1e0a5a79fe4

Migrate to Spree Dev Tools

Replace all development dependencies with:

s.add_development_dependency 'spree_dev_tools'

Replace spec_helper.rb contents with:

https://github.com/spree/spree/blob/777a284b4c70e69d32a05ffa61bbe3905d8f1297/cmd/lib/spree_cmd/templates/extension/spec/spec_helper.rb

Example migrations:

• https://github.com/spree/spree_gateway/pull/357
• https://github.com/spree-contrib/spree-product-assembly/pull/200
• https://github.com/spree/spree_auth_devise/pull/487