Replace/decorate `translation.reader`

Question

I filled a bug but it seams I'm off :p

I just want to replace the service Symfony\Component\Translation\Reader\TranslationReader (translation.reader) with my own class. In fact I want to know how to replace any service of SF4 if I want

translation.reader::addLoader() is normally called by the framework but if I decorate with my own class addLoader is not called.

Can you tell me how I can just drop replace my own service ?

https://github.com/symfony/symfony/issues/28843

Symfony version(s) affected: 4.1.6

Description
Cannot decorate translation.reader (I want to change the default i18n file loading process)

How to reproduce

copy/adapt Symfony\Component\Translation\Reader\TranslationReader to App\Translation\Reader\TranslationReader

Follow https://symfony.com/doc/current/service_container/service_decoration.html

Modify services.yaml

Symfony\Component\Translation\Reader\TranslationReader: ~

App\Translation\Reader\TranslationReader:
    decorates: Symfony\Component\Translation\Reader\TranslationReader

#translation.reader: '@App\Translation\Reader\TranslationReader'

Without the alias : the new service is ignored With the alias : read() is trigger but not addLoader()

Here are the generated injection file getTranslationReaderService.php :

<?php

use Symfony\Component\DependencyInjection\Argument\RewindableGenerator;
use Symfony\Component\DependencyInjection\Exception\RuntimeException;

// This file has been auto-generated by the Symfony Dependency Injection Component for internal use.
// Returns the private 'App\Translation\Reader\TranslationReader' shared autowired service.

include_once $this->targetDirs[3].'/vendor/symfony/translation/Reader/TranslationReaderInterface.php';
include_once $this->targetDirs[3].'/src/Translation/Reader/TranslationReader.php';

return $this->privates['App\Translation\Reader\TranslationReader'] = new \App\Translation\Reader\TranslationReader();

By default it looks like :

use Symfony\Component\DependencyInjection\Argument\RewindableGenerator;
use Symfony\Component\DependencyInjection\Exception\RuntimeException;

// This file has been auto-generated by the Symfony Dependency Injection Component for internal use.
// Returns the private 'translation.reader' shared service.

include_once $this->targetDirs[3].'/vendor/symfony/translation/Reader/TranslationReaderInterface.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Reader/TranslationReader.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Loader/LoaderInterface.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Loader/ArrayLoader.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Loader/FileLoader.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Loader/PhpFileLoader.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Loader/YamlFileLoader.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Loader/XliffFileLoader.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Loader/PoFileLoader.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Loader/MoFileLoader.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Loader/QtFileLoader.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Loader/CsvFileLoader.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Loader/IcuResFileLoader.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Loader/IcuDatFileLoader.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Loader/IniFileLoader.php';
include_once $this->targetDirs[3].'/vendor/symfony/translation/Loader/JsonFileLoader.php';

$this->privates['translation.reader'] = $instance = new \Symfony\Component\Translation\Reader\TranslationReader();

$a = ($this->privates['translation.loader.yml'] ?? $this->privates['translation.loader.yml'] = new \Symfony\Component\Translation\Loader\YamlFileLoader());
$b = ($this->privates['translation.loader.xliff'] ?? $this->privates['translation.loader.xliff'] = new \Symfony\Component\Translation\Loader\XliffFileLoader());

$instance->addLoader('php', ($this->privates['translation.loader.php'] ?? $this->privates['translation.loader.php'] = new \Symfony\Component\Translation\Loader\PhpFileLoader()));
$instance->addLoader('yaml', $a);
$instance->addLoader('yml', $a);
$instance->addLoader('xlf', $b);
$instance->addLoader('xliff', $b);
$instance->addLoader('po', ($this->privates['translation.loader.po'] ?? $this->privates['translation.loader.po'] = new \Symfony\Component\Translation\Loader\PoFileLoader()));
$instance->addLoader('mo', ($this->privates['translation.loader.mo'] ?? $this->privates['translation.loader.mo'] = new \Symfony\Component\Translation\Loader\MoFileLoader()));
$instance->addLoader('ts', ($this->privates['translation.loader.qt'] ?? $this->privates['translation.loader.qt'] = new \Symfony\Component\Translation\Loader\QtFileLoader()));
$instance->addLoader('csv', ($this->privates['translation.loader.csv'] ?? $this->privates['translation.loader.csv'] = new \Symfony\Component\Translation\Loader\CsvFileLoader()));
$instance->addLoader('res', ($this->privates['translation.loader.res'] ?? $this->privates['translation.loader.res'] = new \Symfony\Component\Translation\Loader\IcuResFileLoader()));
$instance->addLoader('dat', ($this->privates['translation.loader.dat'] ?? $this->privates['translation.loader.dat'] = new \Symfony\Component\Translation\Loader\IcuDatFileLoader()));
$instance->addLoader('ini', ($this->privates['translation.loader.ini'] ?? $this->privates['translation.loader.ini'] = new \Symfony\Component\Translation\Loader\IniFileLoader()));
$instance->addLoader('json', ($this->privates['translation.loader.json'] ?? $this->privates['translation.loader.json'] = new \Symfony\Component\Translation\Loader\JsonFileLoader()));

return $instance;

You can see that loaders are not injected when I do the decorating...

Answer 1

I've managed to make it work... but please feel free to comment

I had to create a TranslatorPass to add loaders to the decorating service injection file.

<?php

namespace App\Translation\DependencyInjection;

use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Reference;
use App\Translation\Reader\TranslationReader;

class TranslatorPass implements CompilerPassInterface
{
    private $readerServiceId;
    private $loaderTag;

    public function __construct(string $readerServiceId = TranslationReader::class, string $loaderTag = 'translation.loader')
    {
        $this->readerServiceId = $readerServiceId;
        $this->loaderTag = $loaderTag;
    }

    public function process(ContainerBuilder $container)
    {
        $loaders = array();
        $loaderRefs = array();
        foreach ($container->findTaggedServiceIds($this->loaderTag, true) as $id => $attributes) {
            $loaderRefs[$id] = new Reference($id);
            $loaders[$id][] = $attributes[0]['alias'];
            if (isset($attributes[0]['legacy-alias'])) {
                $loaders[$id][] = $attributes[0]['legacy-alias'];
            }
        }

        if ($container->hasDefinition($this->readerServiceId)) {
            $definition = $container->getDefinition($this->readerServiceId);
            foreach ($loaders as $id => $formats) {
                foreach ($formats as $format) {
                    $definition->addMethodCall('addLoader', array($format, $loaderRefs[$id]));
                }
            }
        }
    }
}

I've put it in the Kernel.php

protected function build(ContainerBuilder $container)
{
    parent::build($container);
    $container->addCompilerPass(new TranslatorPass(), PassConfig::TYPE_BEFORE_OPTIMIZATION, 1000);
}

then

bin/console cache:clear

et voilà !