Language: property hook set hook thrown exceptions must propagate to write site (Zend/zend_property_hooks.c) #9849

Category

language · php-src-strict · PHP 8.4 property hooks

Problem

When a property set hook throws, the exception must propagate to the assignment expression (catchable by user try/catch). Zend resumes normal exception flow from $obj->prop = $value.

Symmetric read-site issue: #10309 — get-hook throws on $obj->prop read must propagate to the fetch expression.

class C {
    public int $x {
        get => $this->x;
        set { throw new Exception('set hook'); }
    }
    private int $x = 0;
}
$c = new C();
try {
    $c->x = 1;
    echo "no-resume\n";
} catch (Throwable $e) {
    echo 'caught: ', $e->getMessage(), "\n";
}
// Zend PHP 8.4+: caught: set hook

Blocked today by #9831 (hook + private backing → compile Cannot redeclare C::$x). After #9831 lands, verify set-hook throw/resume semantics.

php-src reference

• php/php-src Zend/zend_property_hooks.c — set/get hook invocation + exception unwind
• php/php-src Zend/zend_exceptions.c — throw from hook body
• Tests: Zend/tests/property_hooks/property_hooks_set_exception*.phpt, property_hooks_get_exception*.phpt

Repro

Set hook (this issue): test/repro/maintainer_gap_property_hook_set_exception.php

Get hook (#10309): test/repro/maintainer_gap_property_hook_get_throw.php

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php test/repro/maintainer_gap_property_hook_set_exception.php
php bin/vm.php test/repro/maintainer_gap_property_hook_get_throw.php
'

Scope (PHP-in-PHP)

Done when (php-src-strict)

• Set repro prints caught: set hook on VM (no no-resume)
• Language: property hook get hook thrown exceptions must propagate to read site (Zend/zend_property_hooks.c) #10309 get repro green on same VM hook implementation
• Exception class/message match Zend
• JIT write/read paths agree with VM when in scope
• ./script/ci-fast.sh --filter property_hook green

Related

• Language: property hook + private backing field — compile Cannot redeclare (Zend/zend_compile.c) #9831 · Language: property hook get hook thrown exceptions must propagate to read site (Zend/zend_property_hooks.c) #10309 get-hook throws · php-in-php: JIT PropertyHookDispatch — route property hook LLVM through VmPropertyHook PHP not ~475-line monolith (#1492) #10112 · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492