Bug #81015 [Opn->Ver]: Opcache optimization assumes wrong part of ternary operator in if-condition

Edit report at https://bugs.php.net/bug.php?id=81015&edit=1 ID: 81015 Updated by: nikic@php.net Reported by: redwormik at gmail dot com Summary: Opcache optimization assumes wrong part of ternary operator in if-condition -Status: Open +Status: Verified Type: Bug Package: opcache Operating System: Alpine 3.13 (Docker) PHP Version: 8.0.5 Block user comment: N Private report: N Previous Comments: ------------------------------------------------------------------------ [2021-05-06 04:17:55] redwormik at gmail dot com Sorry, changed the output at last minute, but did not change the script. The condition should be (the else-branch output changed): if ($enabled ? true : $value === null) { echo ($value ?? 'NULL') . "\n"; } else { echo "INVALID " . ($value ?? 'NULL') . "\n"; } ------------------------------------------------------------------------ [2021-05-06 04:14:41] redwormik at gmail dot com Description: ------------ I have opcache enabled and opcache.optimization_level at least 0x000000b0 (bits 4, 5 and 8 all set, other irrelevant). When I compare a variable to NULL in a "false" part of a ternary operator in an if-condition, the variable changes to NULL in the respective branch of the if-condition (i.e. if comparison is === NULL, the variable changes to NULL in the if-branch; if comparison is !== NULL, the variable changes to NULL in the else-branch), even though the ternary operator condition is true. Returning the value, changing the condition so it does not use ternary operator, moving the NULL-equality out of the condition to a local variable or comparing to anything else other than NULL all work as expected. Test script: --------------- <?php declare(strict_types=1); function ternary(bool $enabled, ?string $value): void { // the "true" part is not as trivial in the real case if ($enabled ? true : $value === null) { echo ($value ?? 'NULL') . "\n"; } else { echo "INVALID\n"; } } ternary(true, 'value'); ternary(true, null); ternary(false, 'value'); ternary(false, null); Expected result: ---------------- value NULL INVALID value NULL Actual result: -------------- NULL NULL INVALID value NULL ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=81015&edit=1