Symfony 4.3: User Deprecated: The Symfony\Bundle\TwigBundle\Loader\FilesystemLoader class is deprecated since version 4.3 and will be removed in 5.0 …

Question

After upgrading to Symfony 4.3, I\'m getting the following 22 deprecation warnings:

User Deprecated: The Symfony\\Bundle\\TwigBundle\\Loader\\FilesystemLoade

Answer 1

This is due to the deprecation of the templating component, see https://symfony.com/blog/new-in-symfony-4-3-deprecated-the-templating-component-integration

Solution:

1. Remove "symfony/templating" from composer.json
2. Remove this from framework.yaml:

   templating:
       engines:
           - twig
   

3. Run composer update

This should remove all the deprecation warnings.

If you're getting this error

Cannot autowire service "...": argument "$templating" of method "__construct()" references interface "Symfony\Bundle\FrameworkBundle\Templating\EngineInterface" but no such service exists. Did you create a class that implements this interface?

... you're still using the old templating in some service.
Solution: Change the dependency from Symfony\Bundle\FrameworkBundle\Templating\EngineInterface to Twig\Environment:

use Twig\Environment;

private $twig;

public function __construct(Environment $twig)
{
    $this->twig = $twig;
}

See also https://github.com/symfony/symfony/issues/31645