Language: PHP 8.4 property hooks — get/set on properties (Zend parity)

[PurHur]

Category

language

Problem

PHP 8.4 property hooks (get / set on properties) are not parsed or lowered. php-parser / php-cfg may need upgrades; compiler has no hook dispatch on property read/write.

Framework DTOs and validated properties (email, status codes) increasingly use hooks instead of manual __get/__set.

php-src reference

• php/php-src Zend/zend_compile.c — property hook AST → ZEND_PROPERTY_HOOK_GET / SET opcodes
• php/php-src Zend/zend_object_handlers.c — hook invocation on read/write
• php/php-src Zend/zend_property_hooks.c — PHP 8.4 hook runtime (if split in tree)
• RFC: Property Hooks (PHP 8.4)

Repro — set hook (failure today)

Save as property_hook_set.php:

<?php
class User {
    public string $email {
        set (string $value) {
            if (!str_contains($value, '@')) {
                throw new InvalidArgumentException('email');
            }
            $this->email = $value;
        }
    }
}

$user = new User();
$user->email = 'bad';

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php property_hook_set.php'
php property_hook_set.php   # Zend 8.4+: InvalidArgumentException

Runtime	Today
Zend PHP 8.4+	InvalidArgumentException: email
bin/vm.php	Parse / compile error (unsupported property syntax)

Repro — get hook (phase 2 in same issue or follow-up)

<?php
class Box {
    public int $total {
        get => $this->items * $this->unit;
    }
    public function __construct(private int $items, private int $unit) {}
}
$box = new Box(3, 10);
echo $box->total, "\n";

Done when: prints 30 on VM like Zend 8.4.

Scope (this repo)

Module	Path
Parser/cfg	vendor php-parser / php-cfg patches — preserve hook bodies on property nodes
Compiler	lib/Compiler.php — hook dispatch on property fetch/assign
VM	lib/VM.php — invoke hook closures with correct $this; backing value storage
Lint	lib/Lint/UnsupportedRegistry.php — remove mapping when VM path exists
Tests	test/compliance/cases/language/property_hook_set.phpt, property_hook_get.phpt
Matrix	script/capability-syntax.php — row for property hooks

Not: internal_* permanent shims; full JIT/AOT in v1 (VM-first).

Done when

• property_hook_set.php compiles; invalid email throws InvalidArgumentException on VM
• Valid assign persists; read returns stored value
• get hook repro prints 30 (or tracked child issue linked)
• ./script/ci-fast.sh --filter property_hook green
• docs/capabilities-syntax.md row Property hooks → VM yes

Verification

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

Dependencies

• Language: Typed properties, union types, and readonly (PHP 8+) #169 typed properties (hooks compose with types)
• Language: readonly classes (PHP 8.2+) #1360 readonly classes (orthogonal)
• Language: throw expressions and Exception object propagation #195 InvalidArgumentException for repro throws

Links

• Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492 · 🗺️ ROADMAP: Self-host + web-capable PHP subset (living) #78 · PHP 8.4 Language: PHP 8.4 asymmetric property visibility (public/private(set), etc.) #3165 asymmetric visibility (related)

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