OPCache preloading issues

[richardhj]

Affected version(s)

5.3.8

Description

When using OPCache preloading, I get the following error:

PHP Warning:  Can't preload unlinked class Contao\Template@anonymous: Unknown trait Contao\BackendTemplateTrait in /app/vendor/contao/core-bundle/src/Twig/Extension/ContaoExtension.php on line 355

Details on the error: https://stitcher.io/blog/preloading-in-php-74#warning:-can't-preload-unlinked-class

In order for files to be preloaded, their dependencies — interfaces, traits and parent classes — must also be preloaded.

How to enable preloading:

opcache.preload = /var/cache/prod/Shared_KernelProdContainer.preload.php;

[m-vo]

This is only needed for rendering legacy templates from within Twig, thus needing the legacy framework.

Why isn't the rest of the legacy framework an issue with preloading?