New in Symfony 4.3: Deprecating service aliases

January 28, 2019 • Published by Javier Eguiluz

Warning: This post is about an unsupported Symfony version. Some of this information may be out of date. Read the most recent Symfony Docs.

Contributed by Joost van Driel and Renan in #29968.

Deprecations are the key of our backward compatibility promise, which ensures smooth upgrades of your projects between minor versions (e.g. from 4.0 to 4.x). In order to provide a great developer experience, your own Symfony apps can also deprecate services, deprecate config options and even deprecate Twig templates, blocks and macros.

In Symfony 4.3, you'll also be able to deprecate service aliases. When an alias should no longer be used in your application, define it as deprecated with the deprecated configuration option:

YAML
XML
PHP

        1
2
3
4
5
6
7
        # config/services.yaml
services:
    # ...

    app.mailer:
        alias: App\Mail\PhpMailer
        deprecated: ~
    

        1
2
3
4
5
6
7
8
9
10
        <?xml version="1.0" encoding="utf-8"?>
<container xmlns="http://symfony.com/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
    <services>
        <!-- ... -->

        <service id="app.mailer" alias="App\Mail\PhpMailer">
            <deprecated />
        </service>
    </services>
</container>
    

        1
2
3
4
5
        // ...

$container
    ->setAlias('app.mailer', 'App\Mail\PhpMailer')
    ->setDeprecated(true);
    

If this alias is used anywhere in your app, you'll see a generic error message. If you prefer to customize that message, define it using the deprecated option (the only requirement is that the message must include the %alias_id% placeholder):

YAML
XML
PHP

        1
2
3
4
5
6
7
        # config/services.yaml
services:
    # ...

    app.mailer:
        alias: App\Mail\PhpMailer
        deprecated: 'The "%alias_id%" service alias is deprecated.'
    

        1
2
3
4
5
6
7
8
9
10
        <?xml version="1.0" encoding="utf-8"?>
<container xmlns="http://symfony.com/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
    <services>
        <!-- ... -->

        <service id="app.mailer" alias="App\Mail\PhpMailer">
            <deprecated>The "%alias_id%" service alias is deprecated.</deprecated>
        </service>
    </services>
</container>
    

        1
2
3
4
5
        // ...

$container
    ->setAlias('app.mailer', 'App\Mail\PhpMailer')
    ->setDeprecated(true, 'The "%alias_id%" service alias is deprecated.');
    

Published in #Living on the edge

Help the Symfony project!

As with any Open-Source project, contributing code or documentation is the most common way to help, but we also have a wide range of sponsoring opportunities.

Comments

Niels Janssen said on Jan 28, 2019 at 13:37

The title gave me a scare (thought the aliases themselves were being deprecated), but I love the addition!

Javier Eguiluz Certified said on Jan 28, 2019 at 13:50

@Niels I'm sorry! Now I realize that the title could be confusing :( Sadly I cannot update it now to not break the links to this article.

Evgeny said on Jan 28, 2019 at 14:39

I join, I also thought at first that they were abandoning aliases.

Thomas Schulz said on Jan 28, 2019 at 15:00

I thought the same :)

Someone could call this title "click bating" LOL

Antonio Cambados Gondar said on Jan 28, 2019 at 15:32

Same here. This title is going to raise some eyebrows :D

David Garcia said on Jan 28, 2019 at 16:26

I agree with Niels, it was so scary with the title that needed to read the post to confirm it.

@Javier, maybe you can rename the post and make a 301 or 302 redirection?

Cheers,