Extend a core module that is used by another module

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This document describes how to extend a core module that is used by another core module.

Extra consideration must be taken when extending core modules that are already in use by another module.

The following example extends the Cart -> Calculation modules.

The described case is only practical when you are “between” two core bundles. For your own modules, use the general module interface—for example, MyModuleInterface.

1. Modify the interface

Add the foo() method to CalculationFacade on the project level and call it from the Cart module.

The CalculationFacade needs to implement the CartToCalculationInterface because this interface is used in the Cart module.

You can also add your own interface as follows:

<?php
namespace Pyz\Zed\Cart\Dependency\Facade;

use Spryker\Zed\Cart\Dependency\Facade\CartToCalculationInterface as SprykerCartToCalculationInterface;

interface CartToCalculationInterface extends SprykerCartToCalculationInterface
{
    public function foo();
}

2. Add the new method to the interface

The interface needs to extend one from the core.

<?php
namespace Pyz\Zed\Calculation\Business;

use Pyz\Zed\Cart\Dependency\Facade\CartToCalculationInterface;
use Spryker\Zed\Calculation\Business\CalculationFacade as SprykerCalculationFacade;

class CalculationFacade extends SprykerCalculationFacade implements CartToCalculationInterface
{
    public function foo()
    {
        die('<pre><b>'.print_r('!!', true).'</b>'.PHP_EOL.__CLASS__.' '.__LINE__);
    }

}

3. Remove the bridge

In the Cart module’s dependency provider, remove the bridge to directly use the facade.

class CartDependencyProvider extends SprykerCartDependencyProvider
{

public function provideBusinessLayerDependencies(Container $container)
{
	self::provideBusinessLayerDependencies($container);

	$container[self::FACADE_CALCULATION] = function (Container $container) {
		return $container->getLocator()->calculation()->facade();
	};
}

4. Update Factory

In the Cart module, update the business factory with the new interface:

use Pyz\Zed\Cart\Dependency\Facade\CartToCalculationInterface;

class CartBusnessFactory extends SprykerCartBusnessFactory
{
...
	/**
	 * @return \Pyz\Zed\Cart\Dependency\Facade\CartToCalculationInterface
	 */
	public function getCalculationFacade(): CartToCalculationInterface
	{
		return $this->getProvidedDependency(CartDependencyProvider::FACADE_CALCULATION);
	}
...
}

Bridges can only be used on the core level.

We’re constantly improving type declarations of all methods. Because some bridge interfaces might be incompatible with Facade interfaces, this approach doesn’t work. To prevent this, consider module version patch-lock.