Language: empty() on uninitialized typed properties — php-src returns true without throw (regression vs #4912, zend_object_handlers.c) #6787

Category

language | php-src-strict

Problem

Zend treats empty($obj->uninitTyped) and empty(Class::$uninitStatic) as true without throwing; isset() stays false. This compiler throws Error: Typed property … must not be accessed before initialization for empty() on both instance and static uninitialized typed properties.

Closed #4912 + compliance empty_uninitialized_typed_property.phpt codified the throw behavior; php-src parity requires reverting to Zend semantics and updating the compliance expectation.

php-src reference

• php/php-src Zend/zend_object_handlers.c — empty() / isset() on typed properties (skip read when uninitialized)
• php/php-src ext/standard/basic_functions.c — PHP_EMPTY, PHP_ISSET
• php/php-src Zend/zend_types.h — IS_TYPE_UNINITIALIZED guards

Repro (failure today)

<?php
class T {
    public int $i;
    public static int $s;
}
$t = new T();
echo 'isset i=', var_export(isset($t->i), true), ' empty i=', var_export(empty($t->i), true), PHP_EOL;
echo 'isset s=', var_export(isset(T::$s), true), ' empty s=', var_export(empty(T::$s), true), PHP_EOL;

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php repro.php
php bin/vm.php repro.php 2>&1
'

Existing maintainer repro: test/repro/maintainer_empty_uninit_php_src.php (if present).

Scope (this repo)

PHP-in-PHP: no runtime/*.c.

Done when

• Repro prints four lines matching Zend (isset false, empty true) for instance and static
• Direct read $t->i / T::$s still throws Error (unchanged)
• isset() behavior unchanged (already false)
• ./script/ci-fast.sh --filter empty_uninitialized green on VM + JIT/AOT

Verification

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && vendor/bin/phpunit --filter empty_uninitialized'

Strictness

php-src-strict — default CI/compliance must match Zend, not #4912 throw semantics.

Related

• Language: empty() on uninitialized typed property must throw Error (zend_object_handlers.c) #4912 (closed — revert compliance) · Language: isset()/empty() on nullsafe ?-> chain — short-circuit like Zend (zend_compile.c) #4980 (isset on nullsafe) · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492