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Regression: get-only virtual property write Error is "read-only" — Zend "Must not write to virtual property" (re-#18072, Zend/zend_object_handlers.c) #26006
Description
Category
Language · php-src-strict · PHP 8.4 property hooks · PROFILE=8.4
Problem
Writing (or ++ / +=) a get-only virtual hooked property must throw Error with Zend's virtual-property wording. Under PHP_COMPILER_PROFILE=8.4 the VM still emits the readonly-property message, conflating two distinct Error classes (see closed #18072 / #4687 / #9800).
| Repro | Zend 8.4 (php-src) | VM PROFILE=8.4 (2026-07-31) |
|---|---|---|
$c->full = "y" on get-only virtual $full |
Must not write to virtual property C::$full |
Property C::$full is read-only |
$c->n++ on get-only virtual int $n |
Must not write to virtual property C::$n |
Property C::$n is read-only |
Root cause in tree: lib/VM.php enforceVirtualPropertyHookWrite() uses Property %s::$%s is read-only when $virtual is true; the correct helper raiseVirtualPropertyHookRawAccessError() already formats Must not write to virtual property %s::$%s.
php-src reference
- php/php-src
Zend/zend_object_handlers.c— virtual hooked property write withoutset - php/php-src
Zend/zend_property_hooks.c— virtual vs backed classification
PHP implementation target
lib/VM.php—enforceVirtualPropertyHookWrite(): for$virtual === truereuseraiseVirtualPropertyHookRawAccessError(..., isRead: false)(or the same sprintf); do not use the readonly messagelib/JIT/PropertyHookDispatchLlvm.php— keep JIT/AOT Error text aligned- Prefer PHP-in-PHP / existing VM Error materialization; no new
runtime/*.c
Repro
./script/docker-exec.sh -- bash -lc 'PHP_COMPILER_PROFILE=8.4 php bin/vm.php test/repro/property_hook_virtual_write_message.php'<?php
class C {
public string $full {
get => "x";
}
}
$c = new C();
try {
$c->full = "y";
} catch (Error $e) {
echo $e->getMessage(), "\n";
}Expected: Must not write to virtual property C::$full
Done when
- VM (and JIT if in scope) Error message matches Zend exactly for get-only virtual write /
++/+= - Backed get-only and asymmetric
private(set)paths keep their distinct messages (no regress to Language: private(set) property hook write — wrong 'read-only' Error not private(set) message (Zend/zend_property_hooks.c) #9842) - Compliance
.phptundertest/compliance/cases/(ortest/repro/) asserts the Zend string - php-src-strict; no php-compiler-strict shortcut
Activity
PurHur commentedon Jul 31, 2026
claim: Worker Lane C (composer-implementer) — starting this run
PurHur commentedon Jul 31, 2026
Blocker — acceptance criteria vs php-src PHP-8.4 (Worker Lane C)
Claimed this run; no code change — current VM already matches PHP-8.4 for the filed repro.
What VM does today (
PHP_COMPILER_PROFILE=8.4)(
get => "x"virtual get-only vs backed= "ok" { get => $this->name }.)What php-src actually says
PHP-8.4 branch
Zend/zend_object_handlers.c(hooked write, noset,ZEND_ACC_VIRTUAL):That is the external get-only virtual write path — same string the VM emits.
Must not write to virtual propertycomes only fromzend_throw_no_prop_backing_value_access()— used when a hook tries to touch the backing slot of a virtual property (!zend_should_call_hook+ZEND_ACC_VIRTUAL). That path is already wired here asraiseVirtualPropertyHookRawAccessError().master tip recently diverged to
Cannot write to get-only virtual property %s::$%sfor the external path — still notMust not write to virtual property.Conclusion
++on get-only virtualProperty … is read-onlyMust not write to virtual property❌Must not write to virtual propertyCannot write property … without set hookImplementing the filed Done-when would regress php-src-strict vs PHP-8.4 (and still not match master).
Ask for maintainer retarget: close as not-a-bug for PROFILE=8.4, or open a forward-profile ticket for master’s
Cannot write to get-only virtual propertywording (notMust not write…).Unclaiming — Lane C has no other non-
stdlib/ non-extensionimplementation-readyissue this run.PurHur commentedon Jul 31, 2026
claim: Worker Lane C (composer-implementer) — verifying close-out this run
Confirming prior blocker vs php-src PHP-8.4
Zend/zend_object_handlers.c(~1174–1178): external get-only virtual write throwsProperty %s::$%s is read-only. Will add a compliance/repro guard for that Zend string and close as not-a-bug (filed Done-when conflates backing-slotMust not write to virtual property).Language: lock PHP-8.4 get-only virtual write Error as read-only (#26006
PurHur commentedon Jul 31, 2026
Merged #26014 — resolution: not a VM bug under php-src-strict / PROFILE=8.4.
PHP-8.4 external get-only virtual write already emits
Property … is read-only(matchesZend/zend_object_handlers.c). FiledMust not write to virtual propertyconflates the raw backing-slot path. PR adds compliance + repro guards so that wording cannot be “fixed” into a regression.Verification: