October 24, 2018 Javier Eguiluz

Symfony's Backward Compatibility Promise ensures smooth upgrades in your projects because it forbids backward compatibility breaks in minor releases. Instead of changing or removing existing features, we mark them as deprecated and change them in the next major Symfony version.

The UPGRADE-4.2.md document explains all deprecations in details and you'll see them too in the Web Debug Toolbar, the profiler and when running tests. This article summarizes the most important deprecations so you can start upgrading your Symfony 4 apps.

Deprecated a template directory¶ Contributed by

Yonel Ceruto

in #28891. Storing the app templates in src/Resources/views/ is now deprecated. You must store them in the directory defined in the twig.default_path config option in config/packages/twig.yaml , which is templates/ by default.

Deprecated the Kernel name and the root dir¶ Contributed by

Fabien Potencier

in #28809 and #28810. The KernelInterface::getName() method and the kernel.name parameter have been deprecated. There's no alternative to them because this is a concept that no longer makes sense in Symfony applications. If you need a distinctive ID for the kernel of the application, you can use the KernelInterface::getContainerClass() method and the kernel.container_class parameter. Similarly, the getRootDir() method and the kernel.root_dir parameter have been deprecated too. The alternative is to use the getProjectdir() and kernel.project_dir method introduced in Symfony 3.3: 1 2 3 4 5 6 7 8 9 # 'root_dir' is where the Kernel class is stored (src/ by default) and # 'project_dir' is the main project directory services : _defaults : bind : # Before $dataDir : '%kernel.root_dir%/../var/data/' # After $dataDir : '%kernel.project_dir%/var/data/'

Deprecated some console options¶ We've removed the original content of this blog post section because the related change was reverted before the Symfony 4.2 release. You can keep using both the console options and the environment variables: 1 2 3 4 5 # Using options to control the environment and the debug behavior $ php bin/console command_name --env = test --no-debug # Using env vars to control the environment and the debug behavior $ APP_ENV = test APP_DEBUG = 0 php bin/console command_name

Deprecated ContainerAwareCommand ¶ Contributed by

Robin Chalas

in #28415. The ContainerAwareCommand class has been deprecated. It was used in the past to create commands extending from it so they had direct access to the app service container. The alternative is to extend commands from the Command class and use proper service injection in the command constructor, as explained in the main article about the Symfony Console. TIP: use the make:command utility provided by the MakerBundle to generate commands quickly and following the Symfony recommendations.

Deprecated the base Controller class¶ Contributed by

Samuel Roze

in #28243. The base Controller class is the optional class your controllers can extend from to get access to some useful shortcut methods (such us $this->render() ). This Controller class has been deprecated in favor of AbstractController . The new AbstractController base class has the same shortcuts but it's more restrictive about services. You cannot use the $this->get() shortcut to get services. You must follow the modern practices of injecting services in your controller constructor or in the controller action. TIP: use the make:controller utility provided by the MakerBundle to generate controllers quickly and following the Symfony recommendations.

Deprecated process commands as strings¶ Contributed by

Nicolas Grekas

in #27821. Passing commands as strings to the Process class has been deprecated. The alternative is to pass an array of the command parts (name, arguments, options): 1 2 3 4 5 6 7 use Symfony\Component\Process\Process ; // Before $process = new Process ( 'ls -l' ); // After $process = new Process ([ 'ls' , '-l' ]);