Stop overriding CountryManager

Problem/Motivation

Currently Address overrides cores country_manager service in such a way that other modules cannot user this service as it is documented in the API.

See this issue on the Ubercart issue queue.

Ubercart does not alter the first (and by default only) argument to the country_manger service which is of type ModuleHandlerInterface, but Ubercart does add a second argument to the country_manager service. It appears that the Address module also alters the country_manager service. However, the core Drupal country_manager service requires that the first argument to the CountryManager constructor is of type ModuleHandlerInterface.

Proposed resolution

Despite the official documentation stating that the methods used by this module are correct, but:

Note that while swapping services is very easy, you should use caution when making use of this feature. If multiple modules swap the same service, then neither module can predict if their swapped service will win eventually. If a service provides extension capabilities with events, hooks, or by other means, that is definitely more compatible with other extensions.

It seems that perhaps the better solution would be to employ service decorators: Symfony | Lullabot | Phase2

From Lullabot:

The problem arises when there is another module that does the same thing. In that situation either you are replacing that module’s spiced entity manager or that module is replacing your improved alternative. There is no way to get both improvements at the same time.

This is the type of situations where the decorator pattern comes handy. You cannot have this new module inheriting from your manager, because you don’t know if all site builders want both modules enabled at the same time. Besides, there could be an unknown number of modules –even ones that are not written yet– that may create the conflict again and again

Remaining tasks

TBC

API changes

TBC

Data model changes

TBC