Fix fatal error when OPCache preloading is used

[mmenozzi]

Q	A
Branch?	1.11
Bug fix?	yes
New feature?	no
BC breaks?	no
Deprecations?	no
Related tickets	none
License	MIT

While in Symfony 5 the Symfony\Bundle\FrameworkBundle\Templating\EngineInterface was removed, in Sylius there were still references to that interface in docblock comments.

With Sylius 1.11 (with this commit) the type hint has been promoted to a PHP type hint. This normally does not cause any problem because apparently the class loading is lazy and does not try to load the non-existent interface.

But if PHP OPCache preload is used, like suggested here, it appears that PHP switches to eager class loading and you get the following fatal error:

NOTICE: PHP message: PHP Fatal error:  Failed to load class Symfony\Bundle\FrameworkBundle\Templating\EngineInterface used by typed property Sylius\Bundle\ShopBundle\Controller\SecurityWidgetController::$templatingEngine during preloading in Unknown on line 0

With this PR we propose to remove all references to the old interface as Symfony 4 is not supported anymore by Sylius.

[mmenozzi]

The build is red but I don't think it's related to these changes.

[vvasiloi]

Hey @mmenozzi! I finally tried to reproduce this issue and it occurs with PHP 8.0, but not with PHP 8.1.
It's an issue faced by Symfony too and they simply bumped the minimum required PHP version to 8.1 in Symfony 6.1.
Perhaps Sylius should do the same in the next minor release.

@Sylius/core-team I would like to see more opinions on this.

[Ferror]

I was also able to encounter this problem on ex. on Sylius-Standard.

<b>Fatal error</b>:  Failed to load class Symfony\Bundle\FrameworkBundle\Templating\EngineInterface used by typed property Sylius\Bundle\ShopBundle\Controller\SecurityWidgetController::$templatingEngine during preloading in <b>Unknown</b> on line <b>0</b><br />

From my perspective preloading provide value in production. If Symfony 4 is not supported anymore by Sylius and the class EngineInterface was deleted I don't see a reason why we should still keep a reference to it. Especially that we gain is simple typed classes and less ignored phpstan and psalm errors :)

[mmenozzi]

Thank you @Ferror this is exactly what I think.

[vvasiloi]

Removing the reference to that interface will mitigate the problem at hand.
However, if we choose to keep support for PHP 8.0, then we will need a test for preloading to avoid another issue.

[mmenozzi]

Yes I agree it could be useful to have a test for that but I think it should be done in a separate PR. Note also that there's already a kind of test: it's PHPStan/psalm.

[vvasiloi]

Sure, I was also thinking of a separate PR. Psalm/PHPStorm will probably be enough for Sylius code, but another issue might be coming from it's 3rd party dependencies.

[lchrusciel]

@mmenozzi are you willing to do the PR with testing for it?

[GSadee]

Thank you, Manuele! 🥇

[mmenozzi]

@mmenozzi are you willing to do the PR with testing for it?

@lchrusciel do you have any idea on how to test it? AFAIK the preload is done only in the prod environment but we use the test_cached in CI...