Regression: Throwable::getTrace() empty on manual construct — re-#7159 (zend_exceptions.c)

[PurHur]

Category

stdlib · php-src-strict · regression on closed #7159

Problem

When a Throwable is constructed manually inside a user function (not thrown), getTrace() must include the immediate caller frame (Zend: array(1) from probe()). VM returns array(0) for Exception, Error, and TypeError.

CLI top-level new Exception() may show array(0) on both engines; the parity gap is the function-nested construct path used by real code and tests.

php-src reference

• php/php-src Zend/zend_exceptions.c — trace capture on object_init_ex / getTrace()
• php/php-src Zend/zend_execute.c — frame push at call sites

Repro (failure today — verified 2026-06-19)

test/repro-maintainer/throwable_trace_matrix.php:

<?php
declare(strict_types=1);

function probe(string $class): void
{
    $e = new $class('probe');
    foreach (['getTrace', 'getTraceAsString', '__toString'] as $m) {
        echo $class, '::', $m, ' ';
        try {
            $r = '__toString' === $m ? (string) $e : $e->$m();
            echo is_array($r) ? 'array(' . count($r) . ')' : 'string', "\n";
        } catch (Throwable $t) {
            echo get_class($t), "\n";
        }
    }
}

probe(Exception::class);
probe(Error::class);
probe(TypeError::class);

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

Class	Method	Zend PHP 8.2	VM today
Exception	getTrace	array(1)	array(0) ❌
Error	getTrace	array(1)	array(0) ❌
TypeError	getTrace	array(1)	array(0) ❌
all	getTraceAsString	string	string ✅
all	__toString	string	string ✅

Scope (PHP-in-PHP)

Path	Work
lib/VM/Builtin/ExceptionGetTrace.php	synthesize caller frame when trace empty and object not thrown
lib/VM/ExceptionTrace.php	shared trace builder
lib/VM/Builtin/ExceptionConstruct.php (or ctor hook)	capture constructing frame at manual new
JIT/AOT	mirror VM when lowering getTrace()

No new C runtime — read frames from VM call stack metadata.

Done when

• Matrix repro: all three classes show getTrace array(1) on VM (php-src-strict)
• Thrown exceptions still capture throw-site frames only (no regression on Language: #[\SensitiveParameter] attribute — redact parameters in traces (PHP 8.2, Zend parity) #3351)
• Compliance guard: test/compliance/cases/stdlib/throwable_manual_construct_trace.phpt
• ./script/ci-fast.sh --filter throwable_manual_construct_trace green

Verification

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php test/repro-maintainer/throwable_trace_matrix.php'

Related

• Stdlib: Throwable getTrace()/getTraceAsString()/__toString() — VM introspection missing (zend_exceptions.c) #7159 (closed) · Language: #[\SensitiveParameter] attribute — redact parameters in traces (PHP 8.2, Zend parity) #3351 thrown trace · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: lane-c-worker — starting this run

[PurHur]

Merged via #10297

Fix: Snapshot caller frame in Throwable::__construct (manualConstructTrace); getTrace() resolves it when trace is still empty. Throw clears snapshot and fills trace as before.

Verification (docker-exec):

Exception::getTrace array(1)
Error::getTrace array(1)
TypeError::getTrace array(1)
phpunit --filter throwable_manual_construct_trace|throwable_get_trace → OK (2 tests)