Implement TranslatorBagInterface in Translator class

[koertho]

The decorated translator service, introduced in Contao 4.5, doesn't implement the TranslatorBagInterface which the original Symfony service implements. Cause some extension rely on this service and the implementation (so we are, and we are working with Contao 4.4, but got some errors from 4.5 users), this should be fixed (also for 4.5).

See Translator class and TranslatorBagInterface

[dmolineus]

The service uses only the TranslatorInterface. You shouldn't rely on the actual implementation but on the interface.

https://github.com/symfony/symfony/blob/master/src/Symfony/Bundle/FrameworkBundle/Resources/config/translation.xml#L23

If you need to access the catalogue you maybe use the translator.default service.

[leofeyer]

@ausi What do you think?

[ausi]

Because we decorate the original Symfony service, I think we should probably add the bag interface and forward the method call.
Should be as simple as adding:

+ use Symfony\Component\Translation\TranslatorBagInterface;

- class Translator implements TranslatorInterface
+ class Translator implements TranslatorInterface, TranslatorBagInterface

and:

+ public function getCatalogue($locale = null)
+ {
+     return $this->translator->getCatalogue($locale);
+ }

[dmolineus]

I don't mind if the TranslatorBagInterface is also implemented. But keep in mind that any third party bundle could replace the standard translator with a translator which only implements the TranslatorInterface.

[ausi]

The correct way to use it in a third party bundle could be something like:

if ($transaltor instanceof TranslatorBagInterface) { … }

[dmolineus]

Yes, and Contao could provide two decorator one implementing the TranslatorBagInterface and one without depending on the actual service.

It's basically what I do in my backport for Contao 4.4:

$definition      = $container->findDefinition('translator');
$translatorClass = $container->getParameterBag()->resolveValue($definition->getClass());
$decoratorClass  = is_subclass_of($translatorClass, TranslatorBag::class)
        ? LangArrayTranslatorBagTranslator::class
        : LangArrayTranslator::class;

$definition = new Definition(
    $decoratorClass,
    [
        new Reference('netzmacht.contao_toolkit.translation.translator.inner'),
        new Reference('contao.framework')
    ]
);

$definition->setDecoratedService('translator');

[aschempp]

We should totally implement that interface like @ausi mentioned in https://github.com/contao/core-bundle/issues/1674#issuecomment-414838525. Everything else seems wrong to me

[leofeyer]

Implemented in contao/contao@28404321f37587231fb1da978d55d741f7b8a158.