bug #3769 Updates CoreExtension::twig_constant to check for definitio…

…n first to avoid hard crash (Alex Henderson-Roche)

This PR was merged into the 2.x branch.

Discussion
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Updates CoreExtension::twig_constant to check for definition first to avoid hard crash

The behaviour of PHP's constant() method has been updated after php/php-src#9905 was accepted and fixed in PHP 8.1 (and previously changed post PHP 8.0) . This PR prevents a fatal error in the case a constant is supplied that doesn't actually exist.

Commits
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56b3122 Updates CoreExtension::twig_constant to check for definition first to avoid hard crash

src/Extension/CoreExtension.php

@@ -1329,6 +1329,10 @@ function twig_constant($constant, $object = null)
         $constant = \get_class($object).'::'.$constant;
     }
 
+    if (!\defined($constant)) {
+        throw new RuntimeError(sprintf('Constant "%s" is undefined.', $constant));
+    }
+
     return \constant($constant);
 }