ReflectionProperty::skipLazyInitialization() copies invalid constant defaults with OPcache

[DirkTrunkstar]

Description

AI assistance disclosure: this report was prepared with an LLM. The reproduction commands, source build, candidate patch, and test results below were executed and checked.

ReflectionProperty::skipLazyInitialization() gives a typed property an invalid value when its default refers to a class constant and shared-memory OPcache is enabled. This reproduces without Doctrine, Composer, autoloading, a database, or application code.

Reproduced on PHP 8.4.21 and on a clean build of the official PHP 8.4.25 release archive (Linux aarch64, NTS).

Minimal reproduction

Save as repro.php (run from a file, not php -r):

<?php
class Currency {
    public const string EUR = 'EUR';
}
class Product {
    public string $currency = Currency::EUR;
    public function getCurrency(): string { return $this->currency; }
}
$reflection = new ReflectionClass(Product::class);
$product = $reflection->newLazyGhost(static function (Product $product): void {});
$reflection->getProperty('currency')->skipLazyInitialization($product);
var_dump($product->getCurrency());

With OPcache loaded, run:

php -d opcache.enable=1 -d opcache.enable_cli=1 \
    -d opcache.file_cache_only=0 -d opcache.file_cache= \
    -d opcache.preload= -d opcache.file_update_protection=0 \
    -d opcache.optimization_level=0 \
    -d opcache.jit=off -d opcache.jit_buffer_size=0 repro.php

Expected:

string(3) "EUR"

Actual (both tested versions):

Fatal error: Uncaught TypeError: Product::getCurrency(): Return value must be of type string, int|float returned

Removing -d opcache.optimization_level=0 produces UNKNOWN:0 from var_dump() instead, with exit status 0, on both versions. JIT is disabled in both cases. No disk cache is required to reproduce the defect.

Controls

On unmodified PHP 8.4.25, disabling CLI OPcache or enabling disk-only OPcache with a valid writable cache directory returns the expected string(3) "EUR".

On PHP 8.4.21, replacing Currency::EUR with the literal 'EUR' also passes with shared-memory OPcache. So does replacing skipLazyInitialization() with:

$property = $reflection->getProperty('currency');
$property->setRawValueWithoutLazyInitialization($product, $property->getDefaultValue());

Candidate fix and validation

In ext/reflection/php_reflection.c, skipLazyInitialization() reads ce->default_properties_table directly. CE_DEFAULT_PROPERTIES_TABLE() accounts for the resolved defaults held in the class's mutable data under OPcache. The following one-line change fixes the reproduction with both the disabled and default optimizer in the local PHP 8.4.25 build:

--- a/ext/reflection/php_reflection.c
+++ b/ext/reflection/php_reflection.c
@@ -6461,7 +6461,7 @@
 		RETURN_THROWS();
 	}
 
-	zval *src = &object->ce->default_properties_table[OBJ_PROP_TO_NUM(prop->offset)];
+	zval *src = &CE_DEFAULT_PROPERTIES_TABLE(object->ce)[OBJ_PROP_TO_NUM(prop->offset)];
 	zval *dst = OBJ_PROP(object, prop->offset);
 
 	if (!(Z_PROP_FLAG_P(dst) & IS_PROP_LAZY)) {

The PHPT below fails before this change and passes afterward. Running it together with Zend/tests/lazy_objects and ext/reflection/tests on the patched build produced 729 passed, 14 skipped, 0 failed, 0 warned (743 tests total). This is local validation on PHP 8.4.25/aarch64; other architectures and PHP 8.5 were not tested.

PHPT regression test

--TEST--
skipLazyInitialization() preserves a class-constant property default with OPcache
--EXTENSIONS--
opcache
--INI--
opcache.enable=1
opcache.enable_cli=1
opcache.file_cache_only=0
opcache.file_cache=
opcache.optimization_level=0
opcache.file_update_protection=0
opcache.jit_buffer_size=0
--FILE--
<?php
class Currency {
    public const string EUR = 'EUR';
}
class Product {
    public string $currency = Currency::EUR;
    public function getCurrency(): string { return $this->currency; }
}
$reflection = new ReflectionClass(Product::class);
$product = $reflection->newLazyGhost(static function (Product $product): void {});
$reflection->getProperty('currency')->skipLazyInitialization($product);
var_dump($product->getCurrency());
--EXPECT--
string(3) "EUR"

PHP Version

PHP 8.4.25 (cli) (built: Sep 22 2026 10:44:45) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.4.25, Copyright (c) Zend Technologies
    with Zend OPcache v8.4.25, Copyright (c), by Zend Technologies

Also reproduced on PHP 8.4.21 (NTS), Zend OPcache v8.4.21.

Operating System

Alpine Linux 3.23.4, Linux aarch64 (Docker)