bug #4728 Fix opcache preload warning for unlinked anonymous class (OndraM)

This PR was merged into the 3.x branch.

Discussion
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Fix opcache preload warning for unlinked anonymous class

This fixes PHP opcache preload warning, caused by php/php-src#10131 .  The warning is now produced when the preload is initiated.

> Can't preload unlinked class Twig\ExpressionParser\Infix\BinaryOperatorExpressionParser@anonymous: Unknown parent Twig\ExpressionParser\Infix\BinaryOperatorExpressionParser

This started with Twig 3.21, when the anonymous class started to be used in ExtensionSet.

This is a similar woraround as is already used in a TwigBridge, as suggested by `@nicolas`-grekas here symfony/symfony#38533
Also similar fix is in API platform: api-platform/core#3827

Commits
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86997d1 Fix opcache preload warning for unlinked anonymous class

Author: fabpot

src/ExtensionSet.php

@@ -27,6 +27,10 @@
 use Twig\NodeVisitor\NodeVisitorInterface;
 use Twig\TokenParser\TokenParserInterface;
 
+// Help opcache.preload discover always-needed symbols
+// @see https://github.com/php/php-src/issues/10131
+class_exists(BinaryOperatorExpressionParser::class);
+
 /**
  * @author Fabien Potencier <fabien@symfony.com>
  *