Language: $obj->n++ with __get/__set warns Undefined property — Zend silent magic (zend_object_handlers.c)

[PurHur]

Category

Language · php-src-strict / magic property increment

Problem

$obj->n++ when n is not a declared property and the class implements __get/__set must go through magic (Zend zend_std_get_property_ptr_ptr + __get/__set) without Undefined property. The VM already calls __get/__set and the stored value matches (inc=2), but it also emits Warning: Undefined property: M::$n from the #29241 BP_VAR_RW path (warnUndefinedPropertyAfterIncDecRwFetch). That warning is for a missing plain property, not a magic one.

+= on the same object is already silent (parity OK). Inverse of closed #29241 (omit warning when there is no __get).

Probed 2026-08-18 @ aa2e5e8b62 — Zend 8.2.32 vs php bin/vm.php / php bin/jit.php.

Repro	Zend 8.2.32	VM / JIT
$m->n++ with __get/__set backing n=>1	inc=2, no warning	inc=2 + Undefined property: M::$n
$m->n += 2 on the same class	plus=3, no warning	plus=3, no warning (parity OK)

php-src reference

• php/php-src Zend/zend_object_handlers.c — zend_std_read_property / zend_std_get_property_ptr_ptr / __get __set
• php/php-src Zend/zend_vm_def.h — ZEND_POST_INC_OBJ

PHP implementation target

• lib/VM.php — warnUndefinedPropertyAfterIncDecRwFetch (Language: $obj->x++ omits Undefined property E_WARNING — Zend deprecates + warns (re-#29195, zend_object_handlers.c) #29241) must not fire when the class has __get (magic read supplies the value)
• JIT: lib/JIT.php BP_VAR_RW undefined-property warn after create (~12934)
• No new runtime/*.c

Repro

./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro/maintainer_gap_magic_prop_inc.php'
./script/docker-exec.sh -- bash -lc 'php test/repro/maintainer_gap_magic_prop_inc.php'

Done when

• VM prints inc=2 with no Undefined property warning (matches Zend)
• JIT/AOT same (or documented skip with reason)
• Compliance .phpt under test/compliance/cases/language/
• php-src-strict; no php-compiler-strict shortcut

[PurHur]

claim: worker-lane-a — starting this run

[PurHur]

Merged via #32020.

Fix: Skip BP_VAR_RW `Undefined property` warning when `propertyReadUsesMagicGet` applies — VM (`warnUndefinedPropertyAfterIncDecRwFetch`) and JIT (`UndefinedPropertyFetchRuntime::emitWarning` gated on `propertyReadUsesMagicGetAtCompileTime`).

Verified:

• `php bin/vm.php test/repro/maintainer_gap_magic_prop_inc.php` → `inc=2`, no warning
• `php bin/jit.php test/repro/maintainer_gap_magic_prop_inc.php` → same
• `MagicPropIncNoUndefWarnVMTest` / `MagicPropIncNoUndefWarnJITTest` — OK
• `DynPropIncUndefinedWarn` — OK (Language: $obj->x++ omits Undefined property E_WARNING — Zend deprecates + warns (re-#29195, zend_object_handlers.c) #29241 guard unchanged)

Not run: full compliance, differential sweep, bootstrap.