Deprecation warning about return type declaration for JMSHandlerRegistryV2 in Symfony 5.4

[DevMcC]

I recently upgraded to Symfony 5.4 and now I am receiving a deprecration warning about JMSHandlerRegistryV2:

[2021-12-09T11:52:40.460108+01:00] php.INFO: User Deprecated: Method "JMS\Serializer\Handler\HandlerRegistryInterface::getHandler()" might add "callable|object" as a native return type declaration in the future. Do the same in implementation "FOS\RestBundle\Serializer\JMSHandlerRegistryV2" now to avoid errors or add an explicit @return annotation to suppress this message. {"exception":"[object] (ErrorException(code: 0): User Deprecated: Method \"JMS\\Serializer\\Handler\\HandlerRegistryInterface::getHandler()\" might add \"callable|object\" as a native return type declaration in the future. Do the same in implementation \"FOS\\RestBundle\\Serializer\\JMSHandlerRegistryV2\" now to avoid errors or add an explicit @return annotation to suppress this message. at /app/vendor/symfony/error-handler/DebugClassLoader.php:325)"} []

I can't seem to fix this deprecration in my project, so I think it can only be fixed in here instead.
If wanted, I can create a PR to fix this.

I fixed the deprecation in the vendor folder by adding @return to the getHandler method:

    /**
     * {@inheritdoc}
+     *
+     * @return callable|object
     */
    public function getHandler(int $direction, string $typeName, string $format)

Reproduction path:

• Install Symfony 5.4
• Install FOS RestBundle 3.1
• Run bin/console
• See deprecration warning

[ko4a]

Hi
are there any updates ? :)

[pburggraf]

Suppressing the deprecation messages here in this project is probably the wrong way as the "problem" is based on the external interface "HandlerRegistryInterface".

These message should be considered as a hint for the developer to use native return types instead of just rely on doctypes.
For reference and better explaination see the following links:
symfony/symfony#44802 (comment)
sebastianbergmann/php-file-iterator#74