#52636 continuation.

This is another try to simplify even more the prepending extension config strategy for Bundles and Extensions.

Feature: "Import and prepend an extension configuration from an external YAML, XML or PHP file"

Useful when you need to pre-configure some functionalities in your app, such as mapping some DBAL types provided by your bundle, or simply pre-configuring some default values automatically when your bundle is installed, without losing the ability to override them if desired in userland.

class AcmeFooBundleextends AbstractBundle{publicfunctionprependExtension(ContainerConfigurator$container,ContainerBuilder$builder):void    {// Before$config = Yaml::parse(file_get_contents(__DIR__.'/../config/doctrine.yaml'));$builder->prependExtensionConfig('doctrine',$config['doctrine']);// After$container->import('../config/doctrine.yaml');    }}

The "Before" section is limited to importing/parsing this kind of configuration by hand; it doesn't support features likewhen@env, recursive importing, or defining parameters/services in the same file. Further, you can't simply useContainerConfigurator::import() or any*FileLoader::load() here, as they will append the extension config instead of prepending it, defeating the prepend method purpose and breaking your app's config strategy. Thus, you are forced to use$builder->prependExtensionConfig() as the only way.

This is because if you append any extension config using$container->import(), then you won't be able to change that config in your app as it's merged with priority. If anyone is doing that currently, it shouldn't be intentional.

Therefore, the "After" proposal changes that behavior for$container->import().Now, all extension configurations encountered in your external file will be prepended instead. BUT, this will only happen here, at this moment, during theprependExtension() method.

Of course, this little behavior change is a "BC break". However, it is a behavior that makes more sense than the previous one, enabling the usage ofContainerConfigurator::import() here, which was previously ineffective.

This capability is also available forYamlFileLoader,XmlFileLoader andPhpFileLoader through a new boolean constructor argument:

class AcmeFooBundleextends AbstractBundle{publicfunctionprependExtension(ContainerConfigurator$container,ContainerBuilder$builder):void    {// Before// - It can't be used for prepending config purposes// After$loader =newYamlFileLoader($builder,newFileLocator(__DIR__.'/../config/'), prepend:true);$loader->load('doctrine.yaml');// now it prepends extension configs as default behavior// or$loader->import('prepend/*.yaml');    }}

These changes only affect the loading strategy for extension configs; everything else keeps working as before.

Cheers!